Introductory PPT on Metal Carbonyls having its' classification,structure and applications.This is a basic level PPT specially prepared for UG/PG Chemistry students.
Introductory PPT on Metal Carbonyls having its' classification,structure and applications.This is a basic level PPT specially prepared for UG/PG Chemistry students.
what is metal allyl complex
what is the definition of metal allyl complex
what are synthesis of metal allyl complex
what are reaction of metal allyl complex
summary of metal allyl complex
Crown ethers
NOMENCLATURE
GENERAL SYNTHESIS OF CROWN ETHER
AZA CROWN
CRYPTAND
APPLICATIONS
1. SYNTHETIC APPLICTION
Esterification
Saponification
Anhydride formation
Potassium permanganate oxidation
Aromatic substitution reactions
Elimination reactions
Displacement reaction
Generation of carbenes
Superoxide anion
Alkylations – 1. o-alkylations
2. c-alkylations
3. n-alkylations
2. ANALYTICAL APPLICATION
Determination of gold in geological samples
Super critical fluid extraction of trace metal from solid and liquid materials
Application of ionic liquids in analytical chemistry
Oxidation and determination of aldehydes
Crown ethers are used in the laboratory as phase transfer catalyst
OTHER APPLICATION
It is used in photocynation
Resolution of racemic mixture
Benzoin condensation
Hetrocyclisation
Synthesis of furanones
Acetylation of secondary amines in presence of primary amine
Dioxygen complexes, dioxygen as ligand Geeta Tewari
This presentation describes about the preparation, properties, bonding modes, classification and applications of metal Dinitrogen Complexes. Also explains the MO diagram of molecular nitrogen.
what is metal allyl complex
what is the definition of metal allyl complex
what are synthesis of metal allyl complex
what are reaction of metal allyl complex
summary of metal allyl complex
Crown ethers
NOMENCLATURE
GENERAL SYNTHESIS OF CROWN ETHER
AZA CROWN
CRYPTAND
APPLICATIONS
1. SYNTHETIC APPLICTION
Esterification
Saponification
Anhydride formation
Potassium permanganate oxidation
Aromatic substitution reactions
Elimination reactions
Displacement reaction
Generation of carbenes
Superoxide anion
Alkylations – 1. o-alkylations
2. c-alkylations
3. n-alkylations
2. ANALYTICAL APPLICATION
Determination of gold in geological samples
Super critical fluid extraction of trace metal from solid and liquid materials
Application of ionic liquids in analytical chemistry
Oxidation and determination of aldehydes
Crown ethers are used in the laboratory as phase transfer catalyst
OTHER APPLICATION
It is used in photocynation
Resolution of racemic mixture
Benzoin condensation
Hetrocyclisation
Synthesis of furanones
Acetylation of secondary amines in presence of primary amine
Dioxygen complexes, dioxygen as ligand Geeta Tewari
This presentation describes about the preparation, properties, bonding modes, classification and applications of metal Dinitrogen Complexes. Also explains the MO diagram of molecular nitrogen.
Chapter 1: Material Structure and Binary Alloy Systemsyar 2604
This is an introduction to material structure and periodic table system. This topic also describes microstructure of the metals and alloys solidification.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
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.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
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.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
3. Transition metal complexes
• Complex ion has a metal ion at its center with
a number of other molecules or ions
surrounding it, which attached to the central
ion by coordinate (dative covalent) bonds.
• The molecules or ions surrounding the central
metal ion are called ligands
• All ligands are lone pair donors, all ligands
function as Lewis bases.
Transition
metal
complex
metal
ion
ligand
Transition metal (element) is an element that
can form at least one stable ion that has a
partially filled d subshell
d orbital partially filled
5. Example: Fe(H2O)6
3+
• Iron has the electronic structure 1s22s22p63s23p63d64s2
(Fill up 4s before 3d), When it forms an Fe3+ ion it loses the 4s
electrons and one of the 3d electrons to leave 1s22s22p63s23p63d5
(Remove from 4s before 3d)
at the bonding level:
Now, be careful! The single electrons in the 3d level are NOT involved in
the bonding in any way. Instead, the ion uses 6 orbitals from the 4s, 4p
and 4d levels to accept lone pairs from the water molecules.
Before they are used, the orbitals are reorganized (hybridised) to
produce 6 orbitals of equal energy.
9. 2.1. Geometric isomerism
• This occurs in square planar complexes like the Pt(NH3)2Cl2 , cis :
when two ligands are adjacent, trans : when opposite each other.
• In octahedral complexes: When three identical ligands occupy one
face of an octahedron facial (fac). If these three ligands and the
metal ion are in one plane meridional (mer).
• fac-[CoCl3(NH3)3] mer-[CoCl3(NH3)3]
11. 2.3. Structural isomerism
• Occurs when the bonds are themselves different.
• Ionization isomerism
The isomers give different ions in solution although they have the same composition.
[Co(NH3)5Br]SO4 [Co(NH3)5SO4]Br
BaCl2 BaCl2
whit ppt -Ve
• Linkage isomerism
Occurs with ambidentate ligands that can bind in more than one place.
For example: NO2 , SCN
• Coordination isomerism
This occurs when both positive and negative ions of a salt are complex ions and the two
isomers differ in the distribution of ligands between the cation and the anion.
[Co(NH3)6][Cr(CN)6] [Cr(NH3)6][Co(CN)6]
12. 3- Magnetic Properties
Diamagnetic
Paired electron
Spin cancel
No net magnetic effect
[repel by magnetic
field], Zn+2
Weak repulsion
Octahedral (low-
spin), and square-
planar complexes
Paramagnetic
Unpaired electron
Net spin
Net magnetic effect
[attracted by
magnetic field], Mn+2
Weak attraction
Octahedral (high-
spin), and Tetrahedral
complexes
Ferromagnetic
Fe, Co, Ni
certain
materials
(such as iron)
form
permanent
magnets
Strong
14. Color formation: 3d orbital splitting by ligand
• Color in transition metal complexes is generally due to electronic transitions (by
the absorption of light) of two principal types:
1- d-d transitions.
2- charge transfer transitions.
15. 5- Stability
• The affinity of metal ions for ligands is described by
stability constant. This constant, also referred to as the
formation constant Kf can be calculated through the
following method for simple cases:
(X)Metal(aq) + (Y)Lewis Base(aq) ⇌ (Z)Complex
Kf = [Complex]z / [Metal]x [Lewis Base]y
• Large values indicate that the metal has high affinity for
the ligand, provided the system is at equilibrium
Kd = 1/Kf
Kd is the decomposition constant
16. 6- Catalytic properties
Energy of 3d and 4s
orbital's are very close
(Use 3d and 4s electrons
to form weak bond)
Multiple oxidation states
( lose and gain electron
easily)
Catalytic activity
17. Analytical studies
Classical methods
Qualitative
analysis
Chemical
test
Flame test
Quantitative
analysis
Gravimetric
Volumetric
(titration)
Instrumental methods
Spectroscopy
analysis
UV-VIS
spectroscopy
Infra red
spectroscopy
NMR
Atomic absorption
AAS
Mass
X-ray
Separation analysis
Paper
chromatography
Column
chromatography
HPLC
GC
18. Classical methods
Qualitative analysis
• Chemical test
Based on reactions that produce a gas
with distinctive properties, or a colour
change produced by adding a reagent
or the production of a precipitate
• Flame test
Used to detect the presence of certain
elements, based on each element's
characteristic emission spectrum
Quantitative analysis
• Gravimetric
Add reagent precipitation
Filtration draying
weight
• Volumetric
Titration: this method involves the
measurement of volume of
a solution of known concentration
which is used to determine the
concentration of the analyte
19. Separation analysis
1- Paper Chromatography (Thin
Layer Chromatography)
• Chromatography can be used to
identify substances and check on
the purity of a substance
• Stationary phase (chromatography
paper , silica gel sheets, or on
glass sheet.
• Mobile phase : solvent
2- Column chromatography
• Used to isolate chemical
compound from a mixture. Column
chromatography is able to
separate substances based on
differential absorption of
compounds to the absorbent
• To purify liquids (and solids.)
20. 3- Gas chromatography (GC)
• A sample of the substance under
investigation is injected and
vaporized into a tube containing
a carrier gas (mobile phase). The
mobile phase must be an inert or
unreactive gas like nitrogen
4- High performance liquid
chromatography (HPLC)
• Used to separate, identify, and
quantify each component in a mixture.
• It relies on pumps to pass a
pressurized liquid solvent containing
the sample mixture through a column
filled with a solid adsorbent material.
• Each component in the sample
interacts slightly differently with the
adsorbent material, causing different
flow rates for the different
components and leading to the
separation of the components as they
flow out the column.
21. Instrumental methods
1- UV-VIS Spectroscopy
• Used for the quantitative determination of transition metal
ions ( concentration)
•Solutions of transition metal ions can be colored (i.e., absorb visible
light) because d electrons within the metal atoms can be excited from
one electronic state to another.
•The color of metal ion solutions is strongly affected by the presence of
other species, such as certain anions or ligands.
The Beer-Lambert law A= log10 (Io/ I) = ϵ c L
22. 2- Infra-red spectroscopy
• Infra-red spectrum can be used to identify the ligand structure in the transition
metal complex.
• The examined compound absorb some IR frequencies, and the rest of
frequencies which passed through the compound will appear on the detector.
• How much of a particular frequency gets through the compound is measured as
percentage transmittance.
fingerprint
region
23. 3- Atomic absorption spectroscopy
• To defined the metal ion and determine its
concentration in the complex solution
25. 5- Mass spectroscopy
• In order to measure the characteristics of
individual molecules, a mass spectrometer
converts them to ions so that they can be
moved by external electric and magnetic fields. The three
1. The Ion Source : A small sample is ionized, usually to cations
by loss of an electron.
2. The Mass Analyzer : The ions are sorted and separated according to
their mass and charge.
3. The Detector : The separated ions are then measured, and the results
displayed on a chart.
26. 6- X-ray crystallography
• Used for structure determination
• X-ray crystallography is a technique used
for determining the atomic and molecular
structure of a crystal
• A crystallographer can produce a three-
dimensional picture of the density of
electrons within the crystal.
• From this electron density, the mean
positions of the atoms in the crystal can be
determined, as well as their chemical
bonds, their disorder, and various other
information.
27. References
• F. A. Cotton, G. Wilkinson - Advanced Inorganic Chemistry, sixth
edition, A WILEY-INTERSCIENCE PUBLICATION JOHN WILEY &
SONS, INC.1999
• https://www.chemguide.co.uk/inorganic/complexions
• Analytical Chemistry of the Transition Elements by Harry M. N. H.
Irving & Alan T. Hutton, the Encyclopedia of Inorganic Chemistry, First
Edition. 2006