This document summarizes research into the synthesis and characterization of novel metal complexes and their potential biological activity. Specifically, it describes the synthesis of palladium and platinum complexes containing thiosemicarbazone ligands. Various techniques are used to characterize the complexes, including NMR spectroscopy, X-ray crystallography, and UV-visible spectroscopy. Preliminary biological testing of the palladium complexes shows some have higher cytotoxicity than current cancer drugs like cisplatin. Future work involves further testing and structure-activity relationship studies.

1. Synthesis and investigation of biologically active metal complexes
Kelly A. O’Rourke and Dr. Brian J. Anderson
Keene State College
Keene, NH 03435
1. Alderden, R.A.; Hall, M.D.; Hambley, T.W. Journal of Chemical Education 2006, 728-734
2. Kalaivani, P.; Prabhakaran, R.; Poornima, P.; Dallemer, F.; K. Vijayalakshmi, K.; V. Vijaya Padma, V.V.; Natarajan, K. Organometallics 2012, 8323−8332
3. Halder, S.; Peng, S.; Lee, G.; Chatterjee, T.; Mukherjee, Asama Mukherjee; Dutta, S.; Sanyal, U.; and Bhattacharya, S. New Journal of Chemistry 2008, 105-114
!
Background
• Discovery: 19651
• Use: It has been used as a cancer drug since the 1970s
• Function: Binds to the N-7 of guanine on DNA
• Problems: Efficacy is reduced by tumor resistance and toxicity. Platinum
likes to bind to the sulfur in proteins and blood serum
Problems led to the synthesis of other metal compounds
NH
NN
H
N
O
NH2
HN
N N
H
N
O
H2N
Pt
H2N NH2
Pt
NH3H3N
ClCl
Current biologically active metal containing compounds
Compound HL-60 U-937
Cisplatin 7 3.2
Hydroxyurea 204 115
5-FU 266 4.7
BCNU 30.5 12.3
1 2.5 4.8
2 0.6 1.3
Table 1: IC50 value of compounds in µM4
Current Anticancer drugs
NH
NN
H
N
O
NH2
HN
N N
H
N
O
H2N
Pt
H2N NH2
Pt
NH3H3N
ClCl
H
N
O
H2N
OH
hydroxyurea
Cl
H
N
H
N
O
Cl
BCNU
N
H
NH
O
F
5-FU
R
N
N
O
S
NH2
Pd
PPh3
1 R=H
2 R=CH3
Project aims
This is the backbone for the compounds synthesized in the study.
Variations in the backbone will allow for a better opportunity to observe how
structure affects biological activity.
Goal: Synthesize a small library of novel thiosemicarbazone ligands and their
palladium and platinum metal complexes.
Purification
Design the
structure of the
molecule that will
be synthesized
Characterization
Synthesis of
molecule
Biological
testing
Catalysis
Synthesis
Some common characterization techniques are Nuclear Magnetic Resonance,
X-Ray crystallography, Infrared spectroscopy and Ultraviolet- visible spectroscopy
Determines the structure of the molecule
!
This process must happen after a new molecule is synthesized to prove the
structure is what was hypothesized
X-Ray Crystallography
!
• Most accurate method for molecular characterization
• X-ray radiation passed through crystal of a molecule, the X-rays
diffract off of individual atoms in the crystal molecule
• Provides:
• exact connectivity between atoms
• accurate bond distances and angles
• complete identification of the compound
• information about intermolecular/intramolecular interactions
1H and 31P{1H} NMR of 2BPt
Satellite Peaks!
NMR Spectroscopy
!
• One of the most important analytical tools for the synthetic chemist
• Used to determine the number and environment of NMR active nuclei,
like 1H, 31P, and 13C
• Helps elucidate solution state structure
• Shows impurities in the sample,
Ligand synthesis Metal synthesis
Characterization Results
We are looking to test them by DNA binding studies1 and cytotoxicity studies2
These small changes in structure could have a significant impact on their
biological activity.
Future goals
1. Raja, D.S.; Bhuvanesh, N.S.P.; Natarajan, K.; Inorg. Chem. 2011, 50, 12852-12866
2. Halder, S.; Peng, S.; Lee, G.; Chatterjee, T.; Mukherjee, Asama Mukherjee; Dutta, S.; Sanyal, U.; and Bhattacharya, S. New Journal of Chemistry 2008, 105-114
!
The Structure Activity Relationships developed during the biological testing will
lead to the targeted synthesis of the next generation of compounds
!
!
O
OH
R1
H2N
H
N N
H
S
+
EtOH
Reflux
N
H
N N
H
S
R2
OH
R1
R2
M(PPh3)2Cl2
NEt3, MeOH
N
N N
H
O
M S
R2
R1
PPh3
Thiosemicarbazone Metal Complex
Synthesis of thiosemicarbazone ligands and their metal complexes
Ketone Thiosemicarbazide
Thank you to the Keene State Chemistry faculty for their support of my research, especially Dr.
Jasinski for solving structures and creating crystal images. This research was supported by the
National Science Foundation for providing the grants for the 400 MHz NMR spectrometer
(CHE-1337206) and the X-Ray diffractometer (CHE-1039027), as well as NH IN-BRE for funding
my research for the 2014 summer. Finally, thanks to my lab partners Jeff Hall, Steve Doherty, Mike
Freedman, Sean Millikan, Al Keeler and Zac Shalit for their ongoing work on this project.
Acknowledgments
2B-Pd 2B-Pt 1B-Pd
2. Sterics/ electronics
of terminal amine
3. Metal
1. Electronics
of phenyl ring N
N N
M
O
S
H
R2
R1
PPh3
• In vitro growth inhibitory effects of the palladium complexes were evaluated in two human
cell lines, promyelo- cytic (HL-60) and histiocytic lymphoma (U-937).
• Four human clinical drugs, cisplatin, BCNU, 5-FU and hydroxyurea, were used for
comparison.
• The activities are expressed in terms of IC50 value which is the concentration of the
compound required to reduce the cell survival fraction to 50% after 7hr of exposure.
• The lower the IC50 value is, the greater is the cytotoxicity.3
• These novel palladium complexes show higher activity than current anticancer drugs
Cisplatin
2B-Pt
abundance
01.02.03.0
X : parts per Million : Phosphorus31
30.0 20.0 10.0 0 -10.0
Filename = kao-2bPt-2024_PHOSPHORUS-1
Author = Anderson
Experiment = single_pulse_dec.jxp
Sample_Id = kao-2bPt-2024
Solvent = ACETONE-D6
Creation_Time = 28-MAY-2014 10:37:43
Revision_Time = 9-JUL-2014 11:32:55
Current_Time = 9-JUL-2014 11:38:56
Data_Format = 1D COMPLEX
Dim_Size = 26214
Dim_Title = Phosphorus31
Dim_Units = [ppm]
Dimensions = X
Site = JNM-ECS400
Spectrometer = DELTA2_NMR
Field_Strength = 9.389766[T] (400[MHz])
X_Acq_Duration = 0.40370176[s]
X_Domain = 31P
X_Freq = 161.83469309[MHz]
X_Offset = 0[ppm]
X_Points = 32768
X_Prescans = 4
X_Resolution = 2.47707615[Hz]
X_Sweep = 81.16883117[kHz]
X_Sweep_Clipped = 64.93506494[kHz]
Irr_Domain = Proton
Irr_Freq = 399.78219838[MHz]
Irr_Offset = 5[ppm]
Clipped = FALSE
Scans = 64
Total_Scans = 64
Relaxation_Delay = 2[s]
Recvr_Gain = 56
Temp_Get = 18.1[dC]
X_90_Width = 12.7[us]
X_Acq_Time = 0.40370176[s]
X_Angle = 30[deg]
X_Atn = 3[dB]
X_Pulse = 4.23333333[us]
Irr_Atn_Dec = 22[dB]
Irr_Atn_Noe = 22[dB]
Irr_Noise = WALTZ
Irr_Pwidth = 0.116[ms]
Decoupling = TRUE
Initial_Wait = 1[s]
Noe = TRUE
Noe_Time = 2[s]
Repetition_Time = 2.40370176[s]
abundance
01.02.03.04.05.06.07.0
X : parts per Million : Proton
7.0 6.0 5.0 4.0 3.0 2.0 1.0
Filename = kao-2bPt-2024_PROTON-1-7.j
Author = Anderson
Experiment = proton.jxp
Sample_Id = kao-2bPt-2024
Solvent = ACETONE-D6
Creation_Time = 28-MAY-2014 10:42:39
Revision_Time = 9-JUL-2014 11:35:20
Current_Time = 9-JUL-2014 11:35:27
Data_Format = 1D COMPLEX
Dim_Size = 13107
Dim_Title = Proton
Dim_Units = [ppm]
Dimensions = X
Site = JNM-ECS400
Spectrometer = DELTA2_NMR
Field_Strength = 9.389766[T] (400[MHz])
X_Acq_Duration = 2.18365952[s]
X_Domain = 1H
X_Freq = 399.78219838[MHz]
X_Offset = 5[ppm]
X_Points = 16384
X_Prescans = 1
X_Resolution = 0.45794685[Hz]
X_Sweep = 7.5030012[kHz]
X_Sweep_Clipped = 6.00240096[kHz]
Irr_Domain = Proton
Irr_Freq = 399.78219838[MHz]
Irr_Offset = 5[ppm]
Tri_Domain = Proton
Tri_Freq = 399.78219838[MHz]
Tri_Offset = 5[ppm]
Clipped = FALSE
Scans = 16
Total_Scans = 16
Relaxation_Delay = 4[s]
Recvr_Gain = 38
Temp_Get = 18[dC]
X_90_Width = 12.235[us]
X_Acq_Time = 2.18365952[s]
X_Angle = 45[deg]
X_Atn = 3[dB]
X_Pulse = 6.1175[us]
Irr_Mode = Off
Tri_Mode = Off
Dante_Presat = FALSE
Initial_Wait = 1[s]
Repetition_Time = 6.18365952[s]
N
N
H
N
CH3
S
O
O
N
N
H
N
S
O
O
N
N
H
N
CH3
S
O
N
N
H
N
C
H2
S
O
O CH3
1A-Pd
Anderson, 2013
1B-Pd
2A-Pd 2B-Pd
O
C
H2
CH3
M
PPh3
M
PPh3
M
PPh3
M
PPh3
N
N
H
N
CH3
S
O
N
N
H
N
C
H2
S
O
CH3
3A-Pd
3B-Pd
M
PPh3
M
PPh3
O O
M= Pd or Pt
!
N
N NHO
O
Pd S
PPh3
2B-Pd
N
N NHO
O
Pt S
PPh3
2B-Pt
• Currently, 14 novel metal complexes that vary slightly in structure have been synthesized
• The palladium and platinum analogs have been determined to be have the same structure (bond angles, bond
lengths) as determined by X-ray crystallography
• UV- visible spectroscopy have confirmed the analogs are electronically different
• Comparisons between Pd and Pt analogs will allow for the determination of electronic effects on biological activity
Palladium vs. Platinum
• Cost: Platinum is twice the cost of palladium
• Similar reactivity: They are the same size and belong in the same
group in the periodic table
• Both form square planar complexes and are soft Lewis acids
which allows them to form strong bonds to soft Lewis bases such
as sulfur containing molecules.
• Bond strength increases down a group, it can be assumed that
platinum will bind to the ligands tighter than palladium
Garoufis, A.; Hadjikakou, S.K.; Hadjiliadis, N. Coordination Chemistry Reviews 2009, 1384–1397
Palladium vs. Platinum
• Cost: Platinum is twice the cost of palladium
• Similar reactivity: They are the same size and belong in the same
group in the periodic table
• Both form square planar complexes and are soft Lewis acids
which allows them to form strong bonds to soft Lewis bases such
as sulfur containing molecules.
• Bond strength increases down a group, it can be assumed that
platinum will bind to the ligands tighter than palladium
8 9 10 11 12 26.98
26 27 28 29 30
Mn Fe Co Ni Cu Zn Ga
54.94 55.85 58.93 58.7 63.55 65.38 69.72
44 45 46 47 48
Ru Rh Pd Ag Cd
97.9 101.1 102.9 106.4 107.9 112.4 114.8
76 77 78 79 80
Re Os Ir Pt Au Hg
186.2 190.2 192.2 195.1 197 200.6 204.4