NMR SPECTROSCOPY
•Download as PPTX, PDF•
32 likes•2,175 views
This document discusses proton magnetic resonance spectroscopy (NMR spectroscopy), specifically focusing on spin-spin coupling, coupling constants, and the different types of coupling that can occur including geminal, vicinal, and long range coupling. It explains that the coupling constant value increases with increasing bond angle and electronegativity. It also discusses first order spectra and provides examples of geminal, vicinal, and long range coupling, as well as factors that affect coupling constant values.
Report
Share
Report
Share
Recommended
Double resonance
This document discusses double resonance in nuclear magnetic resonance (NMR) spectroscopy. It explains spin decoupling techniques that are used to simplify complex NMR spectra. By irradiating coupled protons, decoupling can eliminate splitting of signals and cause multiplets to collapse into doublets or singlets. This produces easier to interpret spectra. Decoupling is demonstrated on an ethanol sample, where exchanging hydrogens for deuterium causes signals to disappear. Irradiating methyl hydrogens in a molecule can also simplify signals by removing coupling to adjacent protons. Decoupling enhances spectral signals and allows clearer distinction between them.
Noesy [autosaved]
NOESY (Nuclear Overhauser Effect Spectroscopy) is a 2D NMR technique used to identify nuclear spins undergoing cross-relaxation and measure their rates. It provides information about which proton resonances are from protons close in space. NOESY experiments exploit the nuclear Overhauser effect to observe through-space dipolar couplings. One application is in protein NMR to assign structures by sequential walking. It is useful for determining the stereochemistry of biomolecules in solution.
13C-NMR SPECTROSCOPY
This document provides an overview of nuclear magnetic resonance spectroscopy (NMR) focusing on Carbon-13 (13C) NMR. It defines NMR and explains the principles of how atomic nuclei absorb energy from radiofrequency fields in a magnetic field. The summary discusses key aspects of 13C NMR including that 13C is difficult to detect due to its low natural abundance, advantages over 1H NMR, factors affecting chemical shifts, techniques to simplify spectra like decoupling, and applications like DEPT NMR to determine functional groups.
Uv-visible spectroscopy
This document provides an overview of UV-visible spectroscopy. It discusses the electromagnetic spectrum and how light exhibits both wave and particle properties. It explains the basic components and principles of UV-visible spectrometers, including sources such as tungsten lamps and lasers, wavelength selectors like monochromators, sample containers, and various types of detectors. It also covers important concepts such as Beer's law, deviations from Beer's law, and the factors that affect spectroscopic measurements.
FT- NMR
FT-NMR uses Fourier transforms to convert time domain signals from nuclear magnetic resonance into frequency domain spectra. The sample is placed in a strong magnet and exposed to pulses of radio frequency radiation, producing a free induction decay signal that is recorded over time. This time domain signal is then digitized and analyzed using a Fourier transform program on a computer to produce the frequency domain NMR spectrum. FT-NMR provides higher sensitivity than continuous wave NMR, allowing analysis of smaller sample sizes.
Spin spin coupling and decoupling
Spin-spin coupling in NMR spectroscopy occurs when the spin of one proton interacts with the spin of another proton through covalent bonds. This interaction leads to splitting of peaks in the NMR spectrum. The number of peaks (multiplicity) is determined by the number of neighboring protons (n) plus one, following the (n+1) rule. Nuclear magnetic double resonance is a technique that uses two radio frequencies to decouple spins, eliminating spin-spin coupling and resulting in singlet peaks rather than multiplets.
theory and principles of ft nmr
Nuclear magnetic resonance spectroscopy involves subjecting atomic nuclei to magnetic fields and measuring the electromagnetic radiation absorbed and emitted. Fourier transform NMR provides increased sensitivity by combining multiple free induction decay signals measured in the time domain. A Fourier transform converts these signals to an NMR spectrum in the frequency domain. The Michelson interferometer induces interference of light waves by splitting and recombining beams that traveled different path lengths, allowing observation of interference patterns related to the wavelength of light.
13 C NMR Spectroscopy with examples by Dr Anthony Crasto
13C-NMR spectroscopy provides information about carbon atoms in organic compounds. It works by applying a strong magnetic field to excite carbon-13 nuclei, which make up about 1% of naturally occurring carbon. The document discusses several key aspects of 13C-NMR including: principles of NMR spectroscopy; chemical shifts and peak assignments; coupling patterns; techniques to overcome low carbon abundance like signal averaging and Fourier transform; and decoupling methods to simplify spectra. Examples are provided to illustrate predicting chemical shifts and interpreting 13C-NMR spectra.
Recommended
Double resonance
This document discusses double resonance in nuclear magnetic resonance (NMR) spectroscopy. It explains spin decoupling techniques that are used to simplify complex NMR spectra. By irradiating coupled protons, decoupling can eliminate splitting of signals and cause multiplets to collapse into doublets or singlets. This produces easier to interpret spectra. Decoupling is demonstrated on an ethanol sample, where exchanging hydrogens for deuterium causes signals to disappear. Irradiating methyl hydrogens in a molecule can also simplify signals by removing coupling to adjacent protons. Decoupling enhances spectral signals and allows clearer distinction between them.
Noesy [autosaved]
NOESY (Nuclear Overhauser Effect Spectroscopy) is a 2D NMR technique used to identify nuclear spins undergoing cross-relaxation and measure their rates. It provides information about which proton resonances are from protons close in space. NOESY experiments exploit the nuclear Overhauser effect to observe through-space dipolar couplings. One application is in protein NMR to assign structures by sequential walking. It is useful for determining the stereochemistry of biomolecules in solution.
13C-NMR SPECTROSCOPY
This document provides an overview of nuclear magnetic resonance spectroscopy (NMR) focusing on Carbon-13 (13C) NMR. It defines NMR and explains the principles of how atomic nuclei absorb energy from radiofrequency fields in a magnetic field. The summary discusses key aspects of 13C NMR including that 13C is difficult to detect due to its low natural abundance, advantages over 1H NMR, factors affecting chemical shifts, techniques to simplify spectra like decoupling, and applications like DEPT NMR to determine functional groups.
Uv-visible spectroscopy
This document provides an overview of UV-visible spectroscopy. It discusses the electromagnetic spectrum and how light exhibits both wave and particle properties. It explains the basic components and principles of UV-visible spectrometers, including sources such as tungsten lamps and lasers, wavelength selectors like monochromators, sample containers, and various types of detectors. It also covers important concepts such as Beer's law, deviations from Beer's law, and the factors that affect spectroscopic measurements.
FT- NMR
FT-NMR uses Fourier transforms to convert time domain signals from nuclear magnetic resonance into frequency domain spectra. The sample is placed in a strong magnet and exposed to pulses of radio frequency radiation, producing a free induction decay signal that is recorded over time. This time domain signal is then digitized and analyzed using a Fourier transform program on a computer to produce the frequency domain NMR spectrum. FT-NMR provides higher sensitivity than continuous wave NMR, allowing analysis of smaller sample sizes.
Spin spin coupling and decoupling
Spin-spin coupling in NMR spectroscopy occurs when the spin of one proton interacts with the spin of another proton through covalent bonds. This interaction leads to splitting of peaks in the NMR spectrum. The number of peaks (multiplicity) is determined by the number of neighboring protons (n) plus one, following the (n+1) rule. Nuclear magnetic double resonance is a technique that uses two radio frequencies to decouple spins, eliminating spin-spin coupling and resulting in singlet peaks rather than multiplets.
theory and principles of ft nmr
Nuclear magnetic resonance spectroscopy involves subjecting atomic nuclei to magnetic fields and measuring the electromagnetic radiation absorbed and emitted. Fourier transform NMR provides increased sensitivity by combining multiple free induction decay signals measured in the time domain. A Fourier transform converts these signals to an NMR spectrum in the frequency domain. The Michelson interferometer induces interference of light waves by splitting and recombining beams that traveled different path lengths, allowing observation of interference patterns related to the wavelength of light.
13 C NMR Spectroscopy with examples by Dr Anthony Crasto
13C-NMR spectroscopy provides information about carbon atoms in organic compounds. It works by applying a strong magnetic field to excite carbon-13 nuclei, which make up about 1% of naturally occurring carbon. The document discusses several key aspects of 13C-NMR including: principles of NMR spectroscopy; chemical shifts and peak assignments; coupling patterns; techniques to overcome low carbon abundance like signal averaging and Fourier transform; and decoupling methods to simplify spectra. Examples are provided to illustrate predicting chemical shifts and interpreting 13C-NMR spectra.
Coupling constant
Coupling constant
INTRODUCTION
TYPES
Geminal Coupling
Vicinal Coupling
Long Range Coupling
APPLICATION OF NMR SPECTROSCOPY
Fourier-Transform Nuclear Magnetic Resonance Instrumentation (FT-NMR).
Fourier-Transform Nuclear Magnetic Resonance Instrumentation (FT-NMR).Raghavendra institute of pharmaceutical education and research .
In this slide contains instrumentation of Fourier-Transform Nuclear Magnetic Resonance (FT-NMR).
Presented by: P. Venkatesh. (Department of pharmaceutical analysis).
RIPER, anantpur.
PRINCIPLES of FT-NMR & 13C NMR
PRINCIPLES of FT-NMR & 13C NMR
Fourier Transform
FOURIER TRANSFORM NMR SPECTROSCOPY
THEORY OF FT-NMR
13C NMR SPECTROSCOPY
Principle
Why C13-NMR is required though we have H1-NMR?
CHARACTERISTIC FEATURES OF 13 C NMR
Chemical Shifts
NUCLEAR OVERHAUSER ENHANCEMENT
Short-Comings of 13C-NMR Spectra
Factors affecting chemical shift
1) Protons experience different amounts of shielding depending on their chemical environment and electron densities around them.
2) The chemical shift value provides a number independent of the NMR instrument used to measure it.
3) Factors like electronegativity of nearby atoms, hybridization, hydrogen bonding, and anisotropic effects influence the chemical shift values of protons in a molecule.
C 13 NMR
C13 NMR spectroscopy provides information about carbon atoms in molecules. It works based on the absorption of radio waves by carbon-13 nuclei in a magnetic field. There are a few key points:
1) C13 NMR is difficult to analyze due to the low natural abundance of C13 and its weaker magnetic resonance compared to protons.
2) Different types of carbon atoms (CH, CH2, CH3) can be distinguished based on their chemical shifts and coupling patterns. Proton decoupling is used to simplify spectra.
3) DEPT experiments analyze carbon types by enhancing signals from different hybridized carbons (CH, CH2, CH3) in different ways. This allows determining the number and type
Nuclear overhauser effect
The document discusses the nuclear Overhauser effect (NOE), which occurs when two protons are in close proximity within a molecule. Irradiating one proton perturbs its spin distribution and affects the relaxation of the other nearby proton. This causes the intensity of the other proton's signal to increase or decrease, indicating their proximity. The NOE provides information about molecular geometry without requiring coupling between nuclei and can reveal which protons are near each other in a structure.
Factors affecting IR absorption frequency
1. Many factors affect the absorption frequency in IR spectroscopy, including reduced mass, bond strength, hydrogen bonding, electronic effects, and molecular structure.
2. Coupling between vibrations and Fermi resonance can cause frequency shifts and intensity changes. Hydrogen bonding causes broad bands while strong bonds absorb at higher frequencies.
3. Electronic effects like induction, mesomerism, and conjugation influence frequency by altering bond strength. Ring size, hybridization, and physical state also impact the absorption frequency.
Coupling constant
The coupling constant is the distance between peaks in a multiplet in NMR spectroscopy. It is measured in Hertz and does not depend on external magnetic field strength. The value of the coupling constant provides information to distinguish multiplets and can indicate structural features like cis/trans isomers. Coupling occurs between protons close in space, known as geminal, vicinal, and sometimes long-range coupling over several bonds. The coupling constant is affected by factors like bond angle, dihedral angle, and electronegativity of substituents.
Solid State NMR
The document discusses solid state nuclear magnetic resonance (NMR) spectroscopy. It provides examples of applications of solid state NMR including structure determination of organic and inorganic complexes as well as biological molecules, minerals, ceramics, polymers and more. It describes several interactions observed in solid state NMR spectra such as chemical shift anisotropy, dipole-dipole coupling, J-coupling, quadrupolar interactions and magic angle spinning which is a technique to average anisotropic interactions and improve resolution.
Nmr nuclear magnetic resonance spectroscopy
Basics of NMR. Suitable for UG and PG courses.
Includes principle, instrumentation, solvents. chemical shift and factors affecting it. Some problems. resolving agents, coupling constant and much more
C 13 NMR Spectroscopy
1313
C NMR spectroscopy provides information about the number and types of nonequivalent carbon atoms in a molecule. It detects the number of protons bonded to each carbon and the electronic environment of the carbons. The chemical shift range for 1313
C NMR is much wider than for 1H NMR, from 0 to 220 ppm versus 0 to 12 ppm, making individual carbon signals easier to distinguish. Signal averaging and Fourier transform techniques improve the sensitivity of the 1313
C NMR spectrum. Decoupling and DEPT experiments can also provide information about the types of carbon atoms present.
Mass Spectroscopy
Mass spectrometry is a technique that ionizes chemical species and sorts the ions based on their mass-to-charge ratio. It can be used to determine molecular masses and elucidate molecular structures of organic compounds. There are several types of ions produced including molecular ions, fragment ions, and isotope ions. Compounds undergo various fragmentation modes like homolytic cleavage, heterolytic cleavage, retro-Diels-Alder reactions, hydrogen transfers and McLafferty rearrangements. Mass spectrometry has applications in fields like drug development, environmental analysis, and clinical diagnosis.
Chemical shift with c13 nmr
A. 13C NMR spectroscopy provides information about carbon structures in organic compounds. It measures the small differences in magnetic field strength needed for carbon nuclei to resonate. These differences are reported in parts per million (ppm) relative to tetramethylsilane (TMS) as a standard. Factors like electronegativity, hybridization, and hydrogen bonding affect the chemical shift values. 13C NMR has applications in metabolic studies and industrial analyses of solids.
Various factor affecting vibrational frequency in IR spectroscopy.
various factor affecting vibrational frequency in IR,
• Coupled vibrations
• Fermi resonance
• Electronic effects
• Hydrogen bonding
and their examples
1H NMR Spectroscopy
1. 1H NMR spectroscopy involves applying a magnetic field to samples and analyzing the signals produced by hydrogen nuclei as they relax.
2. Key concepts in 1H NMR include chemical shifts, which result from electron shielding and deshielding of hydrogen nuclei, and spin-spin coupling between neighboring hydrogen atoms.
3. 1H NMR spectroscopy is used for structure elucidation of organic and inorganic compounds, as well as for clinical, polymer, and biomolecular applications such as analyzing metabolite levels in tissues.
Cosy,nosy
2D NMR provides more information than 1D NMR by plotting data in a space defined by two frequency axes. There are several types of 2D NMR experiments including COSY, NOESY, and HETCOR. COSY identifies spin-coupled protons by showing cross peaks between protons that are directly bonded. NOESY correlates protons that are near each other in space but not necessarily directly bonded. HETCOR plots 1H and 13C spectra on separate axes and connects carbon signals to bonded proton signals. 2D NMR techniques provide additional structural information about molecules compared to traditional 1D NMR.
Nuclear Magnetic Double Resonance (Decoupling).pptx
This document discusses nuclear magnetic double resonance (decoupling) in NMR spectroscopy. It explains that decoupling involves irradiating a proton to prevent coupling with neighboring protons, simplifying complex spectra. Decoupling causes multiplets to collapse into doublets or singlets, making spectra easier to interpret. It provides an example using ethanol, noting how decoupling removes signals by exchanging protons for deuterium. The document also discusses how decoupling averages spins to zero to remove spin-spin interactions and simplify coupled signals.
C-13 NMR Spectroscopy
This document provides an overview of C-13 NMR spectroscopy. It discusses the history and principle of NMR spectroscopy, focusing on C-13. Key points include: C-13 has a nuclear spin of 1/2, allowing it to be detected by NMR, unlike C-12. The chemical shift range for C-13 is much broader than for proton NMR, from 0-220 ppm. The number of C-13 signals indicates the number of non-equivalent carbon types in a molecule. C-13 coupling is observed with directly bonded protons and other nearby nuclei. Applications of C-13 NMR include structure elucidation of organic and biochemical compounds.
FT NMR
The document discusses Fourier-transform nuclear magnetic resonance (FT-NMR) spectroscopy. It provides an introduction to Fourier transforms and their use in converting time domain NMR spectra to frequency domain spectra. It describes the components of an FT-NMR instrument, including an RF transmitter coil, magnet, receiver coil, and computer. Key advantages of FT-NMR are its dramatic increase in sensitivity over continuous wave NMR, allowing detection of samples under 5 mg, and its ability to rapidly provide high signal-to-noise ratio spectra.
Fragmentation rules mass spectroscopy
Thank you for the presentation on mass fragmentation and its rules. Mass spectrometry is a powerful analytical technique.
Spin spin coupling and coupling constant
Spin-spin coupling occurs between neighboring NMR-active nuclei and causes splitting of NMR spectra. The splitting pattern is related to the number of equivalent hydrogen atoms near the nuclei. The distance between peaks in a split signal is the coupling constant (J) measured in Hertz. Factors like number of bonds between nuclei, bond angles, and molecular rigidity can affect the coupling constant value. Complex coupling results when a set of hydrogen is coupled to two or more nonequivalent neighbors, producing more complex splitting patterns.
Nuclear magnetic resonance 1
NMR use in medical science as MRI, Molecular structure determination. Solution structure of proteins and peptides.
Magnetic resonance imaging. Identification of protein-protein interaction sites is crucial for understanding the basis of molecular recognition.
More Related Content
What's hot
Coupling constant
Coupling constant
INTRODUCTION
TYPES
Geminal Coupling
Vicinal Coupling
Long Range Coupling
APPLICATION OF NMR SPECTROSCOPY
Fourier-Transform Nuclear Magnetic Resonance Instrumentation (FT-NMR).
Fourier-Transform Nuclear Magnetic Resonance Instrumentation (FT-NMR).Raghavendra institute of pharmaceutical education and research .
In this slide contains instrumentation of Fourier-Transform Nuclear Magnetic Resonance (FT-NMR).
Presented by: P. Venkatesh. (Department of pharmaceutical analysis).
RIPER, anantpur.
PRINCIPLES of FT-NMR & 13C NMR
PRINCIPLES of FT-NMR & 13C NMR
Fourier Transform
FOURIER TRANSFORM NMR SPECTROSCOPY
THEORY OF FT-NMR
13C NMR SPECTROSCOPY
Principle
Why C13-NMR is required though we have H1-NMR?
CHARACTERISTIC FEATURES OF 13 C NMR
Chemical Shifts
NUCLEAR OVERHAUSER ENHANCEMENT
Short-Comings of 13C-NMR Spectra
Factors affecting chemical shift
1) Protons experience different amounts of shielding depending on their chemical environment and electron densities around them.
2) The chemical shift value provides a number independent of the NMR instrument used to measure it.
3) Factors like electronegativity of nearby atoms, hybridization, hydrogen bonding, and anisotropic effects influence the chemical shift values of protons in a molecule.
C 13 NMR
C13 NMR spectroscopy provides information about carbon atoms in molecules. It works based on the absorption of radio waves by carbon-13 nuclei in a magnetic field. There are a few key points:
1) C13 NMR is difficult to analyze due to the low natural abundance of C13 and its weaker magnetic resonance compared to protons.
2) Different types of carbon atoms (CH, CH2, CH3) can be distinguished based on their chemical shifts and coupling patterns. Proton decoupling is used to simplify spectra.
3) DEPT experiments analyze carbon types by enhancing signals from different hybridized carbons (CH, CH2, CH3) in different ways. This allows determining the number and type
Nuclear overhauser effect
The document discusses the nuclear Overhauser effect (NOE), which occurs when two protons are in close proximity within a molecule. Irradiating one proton perturbs its spin distribution and affects the relaxation of the other nearby proton. This causes the intensity of the other proton's signal to increase or decrease, indicating their proximity. The NOE provides information about molecular geometry without requiring coupling between nuclei and can reveal which protons are near each other in a structure.
Factors affecting IR absorption frequency
1. Many factors affect the absorption frequency in IR spectroscopy, including reduced mass, bond strength, hydrogen bonding, electronic effects, and molecular structure.
2. Coupling between vibrations and Fermi resonance can cause frequency shifts and intensity changes. Hydrogen bonding causes broad bands while strong bonds absorb at higher frequencies.
3. Electronic effects like induction, mesomerism, and conjugation influence frequency by altering bond strength. Ring size, hybridization, and physical state also impact the absorption frequency.
Coupling constant
The coupling constant is the distance between peaks in a multiplet in NMR spectroscopy. It is measured in Hertz and does not depend on external magnetic field strength. The value of the coupling constant provides information to distinguish multiplets and can indicate structural features like cis/trans isomers. Coupling occurs between protons close in space, known as geminal, vicinal, and sometimes long-range coupling over several bonds. The coupling constant is affected by factors like bond angle, dihedral angle, and electronegativity of substituents.
Solid State NMR
The document discusses solid state nuclear magnetic resonance (NMR) spectroscopy. It provides examples of applications of solid state NMR including structure determination of organic and inorganic complexes as well as biological molecules, minerals, ceramics, polymers and more. It describes several interactions observed in solid state NMR spectra such as chemical shift anisotropy, dipole-dipole coupling, J-coupling, quadrupolar interactions and magic angle spinning which is a technique to average anisotropic interactions and improve resolution.
Nmr nuclear magnetic resonance spectroscopy
Basics of NMR. Suitable for UG and PG courses.
Includes principle, instrumentation, solvents. chemical shift and factors affecting it. Some problems. resolving agents, coupling constant and much more
C 13 NMR Spectroscopy
1313
C NMR spectroscopy provides information about the number and types of nonequivalent carbon atoms in a molecule. It detects the number of protons bonded to each carbon and the electronic environment of the carbons. The chemical shift range for 1313
C NMR is much wider than for 1H NMR, from 0 to 220 ppm versus 0 to 12 ppm, making individual carbon signals easier to distinguish. Signal averaging and Fourier transform techniques improve the sensitivity of the 1313
C NMR spectrum. Decoupling and DEPT experiments can also provide information about the types of carbon atoms present.
Mass Spectroscopy
Mass spectrometry is a technique that ionizes chemical species and sorts the ions based on their mass-to-charge ratio. It can be used to determine molecular masses and elucidate molecular structures of organic compounds. There are several types of ions produced including molecular ions, fragment ions, and isotope ions. Compounds undergo various fragmentation modes like homolytic cleavage, heterolytic cleavage, retro-Diels-Alder reactions, hydrogen transfers and McLafferty rearrangements. Mass spectrometry has applications in fields like drug development, environmental analysis, and clinical diagnosis.
Chemical shift with c13 nmr
A. 13C NMR spectroscopy provides information about carbon structures in organic compounds. It measures the small differences in magnetic field strength needed for carbon nuclei to resonate. These differences are reported in parts per million (ppm) relative to tetramethylsilane (TMS) as a standard. Factors like electronegativity, hybridization, and hydrogen bonding affect the chemical shift values. 13C NMR has applications in metabolic studies and industrial analyses of solids.
Various factor affecting vibrational frequency in IR spectroscopy.
various factor affecting vibrational frequency in IR,
• Coupled vibrations
• Fermi resonance
• Electronic effects
• Hydrogen bonding
and their examples
1H NMR Spectroscopy
1. 1H NMR spectroscopy involves applying a magnetic field to samples and analyzing the signals produced by hydrogen nuclei as they relax.
2. Key concepts in 1H NMR include chemical shifts, which result from electron shielding and deshielding of hydrogen nuclei, and spin-spin coupling between neighboring hydrogen atoms.
3. 1H NMR spectroscopy is used for structure elucidation of organic and inorganic compounds, as well as for clinical, polymer, and biomolecular applications such as analyzing metabolite levels in tissues.
Cosy,nosy
2D NMR provides more information than 1D NMR by plotting data in a space defined by two frequency axes. There are several types of 2D NMR experiments including COSY, NOESY, and HETCOR. COSY identifies spin-coupled protons by showing cross peaks between protons that are directly bonded. NOESY correlates protons that are near each other in space but not necessarily directly bonded. HETCOR plots 1H and 13C spectra on separate axes and connects carbon signals to bonded proton signals. 2D NMR techniques provide additional structural information about molecules compared to traditional 1D NMR.
Nuclear Magnetic Double Resonance (Decoupling).pptx
This document discusses nuclear magnetic double resonance (decoupling) in NMR spectroscopy. It explains that decoupling involves irradiating a proton to prevent coupling with neighboring protons, simplifying complex spectra. Decoupling causes multiplets to collapse into doublets or singlets, making spectra easier to interpret. It provides an example using ethanol, noting how decoupling removes signals by exchanging protons for deuterium. The document also discusses how decoupling averages spins to zero to remove spin-spin interactions and simplify coupled signals.
C-13 NMR Spectroscopy
This document provides an overview of C-13 NMR spectroscopy. It discusses the history and principle of NMR spectroscopy, focusing on C-13. Key points include: C-13 has a nuclear spin of 1/2, allowing it to be detected by NMR, unlike C-12. The chemical shift range for C-13 is much broader than for proton NMR, from 0-220 ppm. The number of C-13 signals indicates the number of non-equivalent carbon types in a molecule. C-13 coupling is observed with directly bonded protons and other nearby nuclei. Applications of C-13 NMR include structure elucidation of organic and biochemical compounds.
FT NMR
The document discusses Fourier-transform nuclear magnetic resonance (FT-NMR) spectroscopy. It provides an introduction to Fourier transforms and their use in converting time domain NMR spectra to frequency domain spectra. It describes the components of an FT-NMR instrument, including an RF transmitter coil, magnet, receiver coil, and computer. Key advantages of FT-NMR are its dramatic increase in sensitivity over continuous wave NMR, allowing detection of samples under 5 mg, and its ability to rapidly provide high signal-to-noise ratio spectra.
Fragmentation rules mass spectroscopy
Thank you for the presentation on mass fragmentation and its rules. Mass spectrometry is a powerful analytical technique.
What's hot (20)
Fourier-Transform Nuclear Magnetic Resonance Instrumentation (FT-NMR).
Fourier-Transform Nuclear Magnetic Resonance Instrumentation (FT-NMR).
Various factor affecting vibrational frequency in IR spectroscopy.
Various factor affecting vibrational frequency in IR spectroscopy.
Nuclear Magnetic Double Resonance (Decoupling).pptx
Nuclear Magnetic Double Resonance (Decoupling).pptx
Similar to NMR SPECTROSCOPY
Spin spin coupling and coupling constant
Spin-spin coupling occurs between neighboring NMR-active nuclei and causes splitting of NMR spectra. The splitting pattern is related to the number of equivalent hydrogen atoms near the nuclei. The distance between peaks in a split signal is the coupling constant (J) measured in Hertz. Factors like number of bonds between nuclei, bond angles, and molecular rigidity can affect the coupling constant value. Complex coupling results when a set of hydrogen is coupled to two or more nonequivalent neighbors, producing more complex splitting patterns.
Nuclear magnetic resonance 1
NMR use in medical science as MRI, Molecular structure determination. Solution structure of proteins and peptides.
Magnetic resonance imaging. Identification of protein-protein interaction sites is crucial for understanding the basis of molecular recognition.
NMR Spectroscopy
This document provides an introduction to NMR spectroscopy and its principles. It discusses the two main types of NMR - proton (1H NMR) and carbon-13 (13C NMR) spectroscopy. It covers the interpretation of 1H NMR spectra, including number of peaks, intensity of peaks, chemical shift, spin-spin splitting/multiplicity, and coupling constants. Interpretation of 13C NMR spectra is also discussed, including chemical shifts and spin-spin splitting. Examples of spectra are provided to illustrate these concepts. The document concludes that NMR spectroscopy is an effective tool for determining molecular structure.
NMR - KRISHNAN
This document provides an overview of nuclear magnetic resonance (NMR) spectroscopy. It begins by defining spectroscopy as the study of interaction between electromagnetic radiation and matter. It then explains that NMR spectroscopy involves absorbing radiofrequency radiation by atomic nuclei placed in a magnetic field. It notes that 1H and 13C NMR are most commonly used to determine the structure of organic molecules by identifying carbon-hydrogen frameworks. The document also provides details on NMR instrumentation, principles, and how NMR spectra are interpreted.
Nmr chemical shift, By Dr. UMESH KUMAR SHARMA AND ARATHY S A
This document provides an overview of NMR spectroscopy, including chemical shift, factors that influence chemical shift like electronegativity and hydrogen bonding, spin-spin coupling and coupling constants. It explains how NMR spectra are obtained and interpreted. Key points covered are how chemical shift is measured relative to a reference compound like TMS, factors that cause shielding or deshielding of protons, splitting of signals due to spin-spin coupling between neighboring protons, and how coupling constants provide information about molecular structure. Diagrams of 1H NMR spectra are provided for ethanol and benzene as examples.
9. m. pharm interpretation of 1 h nmr jntu pharmacy
Nuclear magnetic resonance (NMR) spectroscopy involves analyzing the magnetic properties of atomic nuclei, specifically the spin state of protons. NMR spectra provide information about a compound's structure by indicating the number of different types of protons, the intensity of peaks corresponding to proton count, and peak splitting patterns revealing nearby protons. Chemical shifts along the δ scale indicate the electron density around protons. Factors like electronegativity, hybridization, and hydrogen bonding influence chemical shifts. Coupling constants describe the distance between peaks in multiplets from spin-spin splitting. NMR spectroscopy is useful for analyzing functional groups in compounds like alkanes, alkenes, aromatics, alcohols, amines, and more.
c13 nmr.pptx
This document provides an overview of C13 NMR spectroscopy. It discusses the principles and theory of NMR spectroscopy, the history of C13 NMR, and the information that can be obtained from C13 NMR spectra. Specifically, it explains that C13 NMR spectroscopy allows identification of carbon atoms in organic molecules similarly to how proton NMR identifies hydrogen atoms. It also discusses factors that influence chemical shifts in C13 NMR such as substitution effects, hybridization, and electronegativity. In summary, the document serves as an introduction to C13 NMR spectroscopy, its applications and principles.
Akj p pt carban 13
This document provides an overview of C-13 NMR spectroscopy. It discusses the background of C-13 NMR, how it compares to H-1 NMR, chemical shifts, coupling and decoupling techniques, the NOE effect, Fourier transform methods, and examples of restricted rotation. The key points covered are:
- C-13 NMR provides information about chemically nonequivalent nuclei and their chemical environments. It differs from H-1 NMR in abundance, chemical shift range, and coupling.
- Tetramethylsilane (TMS) is used as the reference standard for both H-1 and C-13 NMR.
- Coupling between nuclei allows their environments to be determined, while decoupling provides separate spectra for each
NMR 7..pptx
NMR spectroscopy is a technique used to determine the structure of organic molecules. It works by applying a strong magnetic field to atomic nuclei, causing them to absorb radio frequencies that are dependent on their chemical environment. This allows differentiation of chemically distinct hydrogen atoms. The frequency of absorption is measured in parts per million relative to a standard, and is influenced by factors like neighboring bonds, substituents, and spin-spin coupling between nuclei. NMR can be used to determine a compound's empirical formula, identify different types of protons, count the number of protons in each type, and elucidate relative stereochemistry and conformations.
Introduction-NMR.pdf
1. Structure Determination by NMR provides lectures on NMR techniques for determining molecular structures, including C13 NMR, 1H NMR, and how NMR works.
2. Biological molecules like proteins and nucleic acids are large and complex, often exceeding 2000 atoms. NMR can be used to determine their 3D structures and dynamics in solution.
3. X-ray crystallography can determine detailed 3D structures but requires crystals, while NMR can be used in solution and its limitations in molecular size are changing.
Paramagnetismo Quântico - Introdução.pdf
1. The document discusses the quantum theory of paramagnetism, explaining that the magnetic moment of an atom or ion in free space is given by the total angular momentum, which is the sum of the orbital and spin angular momentum.
2. It describes how the energy levels of an atom are affected by an applied magnetic field based on the quantum number mj. The magnetic susceptibility is derived from the partition functions of the energy levels.
3. The magnetic moment as a function of temperature is described by the Curie-Weiss law of paramagnetism at high temperatures where x is much less than 1, and the more accurate Brillouin function at lower temperatures.
Spin spin splitting in esr
This document provides an overview of electron spin resonance (ESR) spectroscopy. It discusses key concepts like spin-spin splitting, hyperfine coupling and splitting patterns. Examples are provided to illustrate hyperfine splitting from interactions with nuclei like protons and isotopes. Superhyperfine splitting from interactions between the unpaired electron and multiple equivalent nuclei is also described. The summary concludes with a brief discussion of anisotropic systems and non-spherical symmetry leading to orientation-dependent g-factors.
Nmr spectroscopy
1. 1H NMR spectroscopy is a technique used to analyze compounds by detecting hydrogen nuclei in a magnetic field. It provides information about functional groups, number of nuclei, and structure of compounds.
2. The principle involves hydrogen nuclei absorbing radio frequencies matching their Larmor frequency in an applied magnetic field. This absorption is measured to produce an NMR spectrum.
3. Factors like electronegativity, magnetic anisotropy, and spin-spin coupling influence the chemical shifts observed on the NMR spectrum, allowing identification of functional groups and structure elucidation.
2DNMRSpectroscopy_Advancedspectralanalysis (1).pdf
This document provides an overview of nuclear magnetic resonance (NMR) spectroscopy techniques, including 1D NMR, 2D NMR, COSY, NOESY, INADEQUATE, and HETCOR. It discusses the basics of NMR including chemical shifts, spin-spin coupling, and coupling constants. It describes how 1D NMR can provide information about molecular structure but has limitations for complex molecules. 2D NMR techniques are introduced as a way to obtain additional structural information by introducing a second dimension to the NMR spectrum.
chapter_13_nmr_spectroscopy.pdf
1. NMR spectroscopy is the most important technique for identifying organic molecules. It provides information about the structure of molecules based on the chemical environment of nuclei such as 1H, 13C, and 19F.
2. Chemical shifts are reported in parts per million (ppm) and provide information about functional groups in a molecule based on electron density around nuclei. Coupling between nuclei provides additional structural information.
3. Analysis of chemical shifts, integration of peak areas, multiplicity, and coupling constants allows the determination of functional groups and connectivity in unknown molecules.
Nmr final
Nuclear magnetic resonance (NMR) spectroscopy is a technique that exploits the magnetic properties of atomic nuclei to determine the physical and chemical properties of molecules. It is based on the absorption of radiofrequency radiation by atomic nuclei placed in an external magnetic field. NMR provides detailed information about molecular structure by measuring the energies of spin states in atomic nuclei and the spin-spin coupling between them. Modern NMR instruments use Fourier transform techniques to obtain high resolution spectra. Two-dimensional NMR methods such as COSY and NOESY further aid in structural elucidation by correlating nuclei that are coupled or spatially close.
Nmr spectroscopy
,chemical shift ,shift reagent ,reference standard ,splitting ,coupling ,couling constant ,decoupling ,isotopes
NMR Spectroscopy
This document provides an overview of Nuclear Magnetic Resonance (NMR) spectroscopy. It discusses key NMR concepts like spin quantum number, instrumentation, solvent requirements, relaxation processes, chemical shift, and coupling constants. The presentation was given by Suraj N. Wanjari and covered topics such as NMR principles, instrumentation, factors affecting chemical shift, and applications of 1H NMR and 13C NMR spectroscopy. References on NMR spectroscopy from several analytical chemistry textbooks are also listed.
Introduction about NMR spectroscopy
1. The document discusses the theory of NMR spectroscopy, including how spinning nuclei have magnetic moments that can align with an external magnetic field.
2. It describes how the energy of nuclear spin states changes with increasing magnetic field strength, with the alpha alignment being lower in energy.
3. Chemical shift is defined as the difference in resonance frequency between a nucleus and a reference compound like TMS, and is a measure of the local electronic environment around that nucleus. Chemical shifts are expressed in parts per million (ppm).
NMR
This document provides an overview of NMR spectroscopy. It begins by explaining the fundamental principles, including that NMR spectroscopy detects the absorption of radio waves by atomic nuclei placed in a magnetic field. It then discusses various aspects of interpreting NMR spectra such as chemical shifts, spin-spin coupling and integrals. The document also covers NMR techniques including Fourier transformation, 2D NMR, and relaxation processes. In summary, the document serves as an introduction to NMR spectroscopy and the principles behind analyzing NMR spectral data.
Similar to NMR SPECTROSCOPY (20)
Nmr chemical shift, By Dr. UMESH KUMAR SHARMA AND ARATHY S A
Nmr chemical shift, By Dr. UMESH KUMAR SHARMA AND ARATHY S A
9. m. pharm interpretation of 1 h nmr jntu pharmacy
9. m. pharm interpretation of 1 h nmr jntu pharmacy
2DNMRSpectroscopy_Advancedspectralanalysis (1).pdf
2DNMRSpectroscopy_Advancedspectralanalysis (1).pdf
More from sharmeenkhan15
MAGNETIC PROPERTIES OF TRANSITION METALS ,GARNETS, PEROVSKITES
This document provides an overview of magnetic properties in transition metals, complex compounds, and interstitial compounds. Specifically, it discusses diamagnetism, paramagnetism, and ferromagnetism in transition metals and their magnetic moments. It also examines magnetic properties in complex compounds like perovskites and garnets, referencing several textbooks on inorganic chemistry.
organoplatinum chemistry
This document discusses organoplatinum chemistry and summarizes different organoplatinum compounds. Organoplatinum chemistry involves organometallic compounds containing a carbon-platinum bond. Organoplatinum compounds exist in oxidation states from 0 to IV, with oxidation state II being the most abundant. Organoplatinum(0) compounds contain alkene and alkyne ligands as two electron donors. Organoplatinum(I) compounds are uncommon but are diamagnetic due to Pt-Pt bonds. A historically significant organoplatinum(II) compound is Zeise's salt, obtained from ethylene and potassium tetrachloroplatinate. Organoplatinum(IV) compounds include trimethyl
HANDLING OF HAZARDOUS MATERIALS
Safety is paramount when handling hazardous chemicals in laboratories. Proper protective equipment like gloves and goggles should always be worn. Procedures for the safe storage, use and disposal of dangerous substances must be strictly followed to prevent accidents and protect human health.
MOSSBAUER SPECTROSCOPY
Mossbauer spectroscopy is a technique that uses gamma ray photons to study the chemical environment of atomic nuclei. It works by exposing a solid sample to a beam of gamma rays from a radioactive source, and measuring the absorption of gamma rays by atomic nuclei in the sample. Information about the chemical environment of absorbing nuclei can be obtained from the absorption peaks in the spectra, which show gamma ray intensity as a function of the source velocity. Common radioactive sources used include cobalt-57 and tin-119, and the sample and source must contain nuclei of the same isotope.
mossbauer spectroscopy
Mossbauer spectroscopy involves the resonant absorption of gamma rays by atomic nuclei. It was first observed by Mossbauer in 1958, for which he received the Nobel Prize. The basic principles are that nuclei emitting gamma rays lose a small amount of energy to recoil, while absorbing nuclei must have slightly higher energy for resonance to occur. Doppler shift is used to scan the gamma ray energy through a range and bring the source and sample nuclei into resonance by accelerating the source. The technique provides information about oxidation states, spin states, and local environments of atoms in samples.
SUPER ACID ,SUPER BASE
This document discusses acid-base chemistry and super acids and bases. It defines acids as molecules that can donate protons or accept electron pairs in reactions. Bases are defined as substances that release hydroxide ions in aqueous solutions. Super acids are defined as having a greater acidity than 100% sulfuric acid, while super bases have a high affinity for protons. Examples of super acids include fluorosulfuric acid and triflic acid, while examples of super bases include lithium nitride and potassium hydride. The document discusses applications of super acids and bases in organic synthesis and catalysis.
BIOMINERALISATION
Biomineralization is the process by which living organisms produce minerals. It occurs through two main types: biologically controlled mineralization, where the organism controls mineral growth and placement, and biologically induced mineralization, where the organism modifies the environment to induce mineral formation. Calcium carbonate is a common biomineral found in marine organisms through photosynthesis raising the pH and carbonate concentration to precipitate calcium carbonate. Magnetite is also an important biomineral formed by magnetotactic bacteria, which synthesize chains of magnetic crystals called magnetosomes that act as a biological compass. Examples of other biogenic minerals include apatite in bones/teeth and iron oxides formed by various organisms.
solid solutions
This document discusses different types of solid solutions, including substitutional, interstitial, and complex solid solutions. It describes the requirements for forming substitutional solid solutions, such as similar ion size and charge. Interstitial solid solutions occur when the solute atom is smaller than the solvent atoms. Complex solid solutions can form through substitution of higher or lower valence cations, creating cation or anion vacancies or interstitials. X-ray powder diffraction is discussed as an experimental method to study solid solutions by determining unit cell dimensions and composition across a series.
classification of lewis bases
This document discusses the classification of Lewis bases based on frontier molecular orbital topology. It defines Lewis acids and bases and describes four types of Lewis bases: s-HOMO Lewis bases which have spherical highest occupied molecular orbitals; complex anion Lewis bases which have a hypervalent central cation saturated with anionic ligands; lobe-HOMO Lewis bases which are electron lone pair donor species with the electron pair in an sp3, sp2 or sp hybrid orbital; and π-HOMO Lewis bases which have delocalized electrons in highest occupied molecular orbitals over two or more p-orbitals such as those in alkenes, dienes and trienes. Examples are provided for each classification.
solid solutions
This document discusses solid solutions, which occur when atoms of a solute are present in the lattice of a solid solvent. It describes two types of solid solutions: substitutional and interstitial. Substitutional solid solutions can be ordered or disordered, depending on whether solute atoms randomly or regularly substitute for solvent atoms in the lattice. Interstitial solid solutions involve solute atoms fitting into the spaces between solvent atom sites in the lattice. References on inorganic structural chemistry and crystal chemistry are also provided.
liquid crystals
Liquid crystals are a state of matter that has properties between those of a conventional liquid and solid crystal. They may flow like a liquid but their molecules can be oriented in a crystal-like way. Friedrich Reinitzer discovered important features of cholesteric liquid crystals in 1888, including thermotropic, lyotropic, and metallotropic phases. Common liquid crystal phases are nematic, smectic, and cholesteric/chiral. Blue phases have a regular three-dimensional cubic structure of defects with a lattice period of several hundred nanometers. Liquid crystals can flow like liquids due to loss of positional order, and transition between solid and liquid crystal states caused by temperature change gives rise to thermotropic liquid crystals
line defects
This document is a paper on inorganic chemistry that discusses line defects in solids, specifically edge and screw dislocations. It was written by Sakshi Mishra for their M.Sc. Part 2, Semester 3 course. The paper references common solid state chemistry textbooks and building construction resources.
mossbauer spectroscopy
This document is about Mossbauer spectroscopy and discusses isomer shift, quadrupole interaction, and magnetic interaction. It analyzes Mossbauer spectroscopy and explains these three phenomena, and concludes with references for further reading on physical methods for chemists, instrumental methods of chemical analysis, and modern aspects of inorganic chemistry.
Inorganic REACTION MECHANISM
This document discusses techniques for determining the rate of inorganic chemical reactions. It describes three main techniques: direct chemical analysis, spectrophotometric methods, and electrochemical and flow methods. Direct chemical analysis involves directly analyzing reactants or products during a chemical change. Spectrophotometric methods measure how much a substance absorbs light at different wavelengths. Electrochemical and flow methods are useful for following the progress of chemical reactions, especially in sensor applications where reaction progress can determine analyte concentration. The document provides examples and details of each technique.
TWO COMPONENT SYSTEM
The document discusses different types of compound formations including compounds with congruent and incongruent melting points. It defines key terms like phase, component, degree of freedom, and explains concepts like the phase rule and how it relates the number of components, phases, and degrees of freedom in a system. Examples of systems forming compounds with congruent melting points like zinc-magnesium and systems forming compounds with incongruent melting points like picric acid-benzene are provided along with diagrams showing their phase diagrams.
DIODE ARRAY AND FLUORESCENCE DETECTOR
This document discusses HPLC detectors, focusing on diode array and fluorescence detectors. It provides details on how HPLC works to separate mixtures and describes common HPLC detectors. It explains that diode array detectors can detect absorption across a range of wavelengths to identify components, while fluorescence detectors use excitation and emission wavelengths to selectively detect some components. Both provide advantages like sensitivity and specificity over other detectors.
FRENKEL DEFECT
This document discusses Frenkel defects in solid state chemistry. It begins by introducing the topic of types of defects, specifically Frenkel defects, and mentions deriving the Frenkel defect. References are provided from three solid state chemistry textbooks on pages discussing Frenkel defects and solid state chemistry.
MASS SPECTROMETRY
This document discusses the topic of mass spectrometry and its applications in organic chemistry. It covers the basic principles of mass spectrometry, including molecular ion peaks, base peaks, and the nitrogen rule. It also examines fragmentation patterns in different classes of organic compounds. The document provides references for further reading on spectroscopy techniques and the spectroscopic identification of organic molecules.
ATOMIC ABSORPTION SPECTROSCOPY
The document discusses atomic spectroscopy based on plasma sources. It introduces atomic spectroscopy and explains that it involves using plasma sources to produce excited atoms that emit electromagnetic radiation of characteristic wavelengths. The principle and instrumentation of atomic spectroscopy are described. Various applications of atomic spectroscopy are also mentioned, such as its use in chemical analysis. References are provided for further reading on the topic.
TOXICITY OF METALLIC SPECIES
This document discusses the toxicity of various metallic species, including arsenic, copper, and chromium. It provides an introduction and then examines the sources, effects, and treatments for the toxicity of each metal, addressing arsenic toxicity first, followed by copper toxicity, and ending with chromium toxicity. It lists references used at the end.
More from sharmeenkhan15 (20)
MAGNETIC PROPERTIES OF TRANSITION METALS ,GARNETS, PEROVSKITES
MAGNETIC PROPERTIES OF TRANSITION METALS ,GARNETS, PEROVSKITES
Recently uploaded
THEMATIC APPERCEPTION TEST(TAT) cognitive abilities, creativity, and critic...
THEMATIC APPERCEPTION TEST(TAT) cognitive abilities, creativity, and critic...Abdul Wali Khan University Mardan,kP,Pakistan
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skillsWhat is greenhouse gasses and how many gasses are there to affect the Earth.
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
The binding of cosmological structures by massless topological defects
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
Phenomics assisted breeding in crop improvement
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/8.Isolation of pure cultures and preservation of cultures.pdf
Isolation of pure culture, its various method.
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
Applied Science: Thermodynamics, Laws & Methodology.pdf
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Equivariant neural networks and representation theory
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
20240520 Planning a Circuit Simulator in JavaScript.pptx
Evaporation step counter work. I have done a physical experiment.
(Work in progress.)
Cytokines and their role in immune regulation.pptx
This presentation covers the content and information on "Cytokines " and their role in immune regulation .
SAR of Medicinal Chemistry 1st by dk.pdf
In this presentation include the prototype drug SAR on thus or with their examples .
Syllabus of Second Year B. Pharmacy
2019 PATTERN.
Randomised Optimisation Algorithms in DAPHNE
Slides from talk:
Aleš Zamuda: Randomised Optimisation Algorithms in DAPHNE .
Austrian-Slovenian HPC Meeting 2024 – ASHPC24, Seeblickhotel Grundlsee in Austria, 10–13 June 2024
https://ashpc.eu/
Recently uploaded (20)
THEMATIC APPERCEPTION TEST(TAT) cognitive abilities, creativity, and critic...
THEMATIC APPERCEPTION TEST(TAT) cognitive abilities, creativity, and critic...
What is greenhouse gasses and how many gasses are there to affect the Earth.
What is greenhouse gasses and how many gasses are there to affect the Earth.
The binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defects
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...
Applied Science: Thermodynamics, Laws & Methodology.pdf
Applied Science: Thermodynamics, Laws & Methodology.pdf
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...
Equivariant neural networks and representation theory
Equivariant neural networks and representation theory
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
20240520 Planning a Circuit Simulator in JavaScript.pptx
20240520 Planning a Circuit Simulator in JavaScript.pptx
Cytokines and their role in immune regulation.pptx
Cytokines and their role in immune regulation.pptx
NMR SPECTROSCOPY
- 1. ORGANIC CHEMISTRY BY SMITA. S. JADHAV MSC:-1 SEM :-2
- 2. TOPIC:- NMR SPECTROSCOPY PROTON MAGNETIC RESONANCE SPCTROSCOPY
- 3. CONTENT:- Proton Magnetic Resonance Spectroscopy:- Spin-spin Coupling Coupling Constant(j) Factor Affecting (J) Geminal, Vicinal, And Long Range Coupling First Order Spectra
- 10. FACTORS AFFECTING (J) VALUE :- the value of coupling constant is increases with increase in bond angle. the increase in the electronegativity of an atom or group with withdraw sigma electron , increase the value of coupling constant. the value of (j) decreases with the substituent withdraw electron from pi bonded carbon
- 11. TYPES OF COUPLING:- GEMINAL COUPLING VICINAL COUPLING LONG RANGE COUPLING FIRST ORDER SPECTRA
- 12. GEMINAL COUPLING:- two bond coupling are common in NMR spectra, they are called geminal coupling . because the two nuclei are attached to same carbon atom it self. the two bonds coupling are smaller than one bond coupling. in case of geminal protons the value of (j) depends upon H- C--H bond angle called as bond dihydral angle.
- 13. VICINAL COUPLING :- three bond coupling are called vicinal coupling because the interacting atom are attached to the adjucent carbon atom ‘c’ . it is designated as J3 for the vicinal proton the coupling constant values with the dihydral angle. a plot of (j) values verses dihydral angle of vicinal proton is as shown when the two bonds are parallel or antiparallel the coupling constant of the greatest value of the other hand if the two C-H bond are perpendicular there is little or no spin interaction hence j3 values are minimum.
- 14. LONG RANGE COUPLING:- usually no coupling is observed if the distance between the two absorbing nuclei is more than three covalent bonds . but in unsaturated compounds or in fluoro compounds, appreciable coupling is observed with the help of high resolution spectrometers even if the concerned nuclei are three bonds apart it is called long range coupling. EXAMPLE:- CH3-CH=CH2
- 15. FIRST ORDER SPECTRA:--- spectra that can be interprited by the N+1 rule are called 1st order spectra if two sets of nuclei are seprated by a large chemical shift they generally shows speeds order spectra CHEMICALAND MAGNETIC EQUIVALENT :- two or more atoms are symmetrically equivalent , they are set to be chemically equivalent a plane or axis of symmetry makes the hydrogen atom chemically equivalent.
- 16. REFERENCES:- WILLIAM KEMP( THIRD EDITION)PAGENO:-135-148 ,152-164 . JAG MOHAN(SECOND EDITION)PAGE NO:-241-258. ORGANICCHEMISTRY(SHEATH PUBLICATIONS),C.T.BHASTANA, U.B.RAICHORA, M.A.DAVE , J.N.KADALI, PAGE NO:-391-396. P.S.KALASI, 5th EDITIONSPECTROSCOPYOF ORGANICCOMPOUND, PAGE NO:-183- 240 , 269. MECHANISMIN ORGANICCHEMISTRY,PETERSYKES, 6th EDITION, PAGE NO:-123- 134.