Tuning Reactivity of Platinum(II) Complexes

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c. Oxidizability: Ligands that are readily oxidized, i.e. strong reducing agents d. Solvation Energy: are good nucleophiles. The oxidizability of the ligands are characterised by their electrode reduction potentials. Those ligands that are strongly solvated are considered weak nucleophiles because energy is required to free the nucleophile from the bonded solvent, before it can coordinate to the metal centre. e. Metal Centre: Nucleophilicity depends much on the nature of the metal centre. Heavier elements are better polarised in the transition state. The corresponding rates of substitution follow the trend: Ni(II)>> Pd(II) >> Pt(II). This factor limits the application of the nucleophilicity scales in the Inorganic Chemistry as most are dependent on the nature of the metal centre. Studies which were performed on complexes of Pt(II) established that the nucleophilic reactivity of different nucleophiles is of the order: 36 R3P > TU > − I ~ − > OH > F¯ − SCN ~ 3− N > − NO 2 > − Br > py > aniline ~ olefin ~NH3 ~ − Cl > H2O However, it should be noted that the reactivity of the entering nucleophile is more of a function of its polarisability than its base strength. In protic solvents (hydrogen bond donors) the direct relationship between nucleophilicity and its pKa is the inverse. 37 This results from the ion-dipole interactions between the solvent and the nucleophile. In aprotic solvents nucleophilicity remains directly related to basicity. The most comprehensive study on the relative reactivity and nucleophilicity was performed using trans-[Pt(py)2Cl2] in methanol at 30 ° C (Equation 2.40) that is not easily distorted, prefer hard bases, e.g. Li + , Mg 2+ and F ¯ . Similarly, soft acids, i.e. those metal ions that are large, bear a low charge and have a valence electron shell that is easily distorted or removed, prefer soft bases, e.g. Pt 2+ and SCN ¯. 24
trans-[Pt(py) 2 Cl 2 ] + Y n trans-[Pt(py) 2 (Y)Cl] (n+1) + Cl - (2.40) When trans-[Pt(py)2Cl2] was used as the standard, the nucleophilicity constant of the incoming ligand, n ° pt, is defined as: 26,35 log( k y k o s ) = n o Pt where, kY = the measured second-order rate constant for the reaction of the entering nucleophile, Y 25 (2.41) k o S = the second-order rate constant for attack of the solvent (methanol) in an associative mechanism and is equal to {ks/[MeOH]} kS = the rate constant for attack of the solvent, MeOH, on the complex. At 30 °C, the concentration of pure methanol is assumed to be 24.3 M and the equation simplifies to: n o pt = npt + 1.39 (2.42) By definition the n o pt for methanol as the entering group is zero, while that for triphenylphosphine ligand, {(Ph)3P}, is a high value of 8.99. The typical n o pt data obtained for Equation 2.42 is summarised in Table 2.1 for different entering nucleophiles (Y).
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Tuning Reactivity of Platinum(II) C
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Declaration This thesis report is b
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Abstract Systematic kinetic and the
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Table of contents Acknowledgements
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2.5.5 Effect of Non-participating G
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5.2.1 Chemical and Solutions ......
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7.2 Experimental Section ..........
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procurements, Messers P. Forder and
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Figure 2.2 Potential energy profile
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Figure 4.6 Concentration dependence
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Figure 6.1 Spectrophotometric titra
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List of Tables Table 2.1 A selectio
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Table 6.4 Summary of rate constants
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TU thiourea DMTU 1,3-dimethyl-2-thi
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Table of Contents-1 Chapter 1 .....
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1.0 Introduction 1.1 Cancer Disease
Page 34 and 35: toxic potential. The most well-know
Page 36 and 37: 1.3.2.2 Cellular Uptake Cisplatin i
Page 38 and 39: H 3N OH 2 Pt H 3N OH 2 Active Pt(II
Page 40 and 41: transformational pathways that comp
Page 42 and 43: the hydrolysis of the complex, wher
Page 44 and 45: 1.3.4 Terpyridine Platinum(II) Comp
Page 46 and 47: H 3 N Cl Pt NH 3 H 3 N NH 2 (CH 2 )
Page 48 and 49: 1.4 Kinetic Interest The platinum-b
Page 50 and 51: 3. The effect of varying the positi
Page 52 and 53: 17 R. A. Henderson, The Mechanism o
Page 54 and 55: Altona J. H. van Boom, G. A. van de
Page 56 and 57: 76 (a)J. Kašpárková, J. Zehnulov
Page 58 and 59: Table of Contents-2 Chapter Two ...
Page 60 and 61: List of Tables Table 2.1: A selecti
Page 62 and 63: The mononuclear Pt(II) complexes 1-
Page 64 and 65: Potential Energy R + X RX 1 transit
Page 66 and 67: For the associative mechanism (A),
Page 68 and 69: the concentration of one of the rea
Page 70 and 71: k obs , s -1 0.00030 0.00025 0.0002
Page 72 and 73: k = Ae -Ea/RT 2.14 lnk = lnA - E a
Page 74 and 75: = 23.76 + R Hence, a plot of ln ⎛
Page 76 and 77: iii. # Δ V ≈ 10 cm3 mol-1 featur
Page 78 and 79: conventional methods are classical
Page 80 and 81: Figure 2.6: Schematic diagram of a
Page 82 and 83: The light transmitted from the samp
Page 86 and 87: Table 2.1: A selection of n o pt va
Page 88 and 89: eaction with different nucleophiles
Page 90 and 91: eaction site from direct attack by
Page 92 and 93: PEt 3 PEt 3 R PEt 3 Pt Pt Y Y Cl R
Page 94 and 95: direct displacement of the leaving
Page 96 and 97: therefore, weaken the bond of the l
Page 98 and 99: σ-Donation According to classical
Page 100 and 101: References 1 (a) J. Reedijk, Chem.
Page 102 and 103: 34 R. B. Jordan, Reaction Mechanism
Page 104 and 105: Table of Contents-3 Chapter 3.The
Page 106 and 107: Chapter 3 The π-Acceptor Effect in
Page 108 and 109: In order to extend our understandin
Page 110 and 111: after which water was added to quen
Page 112 and 113: O CH 3 + I + N O oH - N O O 7 CH 3
Page 114 and 115: 84% (34.7 mg, 0.0618 mmol). 1 H NMR
Page 116 and 117: PhCN PhCN Pt Cl Cl + N N CH 3 N CH
Page 118 and 119: Complex Structure HOMO LUMO PtCl CH
Page 120 and 121: The geometry-optimised structures i
Page 122 and 123: against the concentration of the in
Page 124 and 125: Table 3.2: Summary of the second-or
Page 126 and 127: constants of CH3PhisoqPtCl decrease
Page 128 and 129: with π*-orbitals of the ligand. Th
Page 130 and 131: 3.6 References 1 D. Rosenberg, L. V
Page 132 and 133: 30 Microcal TM Origin TM Version 5.
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Figure S3.1: Kinetic trace at 448 n
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ln(k 2 /T) -6.0 -7.5 -9.0 -10.5 -12
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Table S3.3b: Average observed rate
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Table S3.5b: Temperature dependence
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Table S3.8: DFT calculated electros
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List of Figures Figure 4.1: Structu
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Table 4.2: Summary of pKa values fo
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4.1 Introduction Platinum compounds
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cis geometry, leading to dramatic c
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ligand was added to the [{cis-PtCl(
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spectra were measured in and refere
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4.3.1 DFT calculated Optimized Stru
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Table 4.1: A summary of the DFT cal
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H2O-Pt-L-Pt-OH2 H2O-Pt-L-Pt-OH2 H2O
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electrophilicity and acidity of the
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(A) 18 Absorbance 0.08 0.07 0.06 0.
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k obs(3 rd ) , s -1 -5 6.00x10 TMTU
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4.3.4 Kinetics with NMR The substit
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ln([ML] t ) 4.0 3.5 3.0 2.5 2.0 1.5
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ln(k 2(1 st ) /T) -3.5 -4.0 -4.5 -5
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Comple x Table 4.4: Summary of Acti
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The decrease in reactivity of 2,6pz
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Table 4.5: DFT calculated (NBO) cha
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eaction proceeds via bimolecular pa
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References 1 T. Storr, K. H.Thomson
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36 D. Jaganyi, D. Reddy, J.A. Gerte
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Appendix 4 THE INFLUENCE OF THE PYR
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Absorbance at 368. 0 nm 0. 0 8 0. 0
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Table S4.3: Average observed rate c
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k nd obs(2 ) , s-1 0.003 TU DMTU TM
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k obs2 , s -1 2.40x10 -4 2.20x10 -4
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Table S4.13: Average observed rate
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k obs(1 st ) , s -1 0.06 0.04 0.02
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ln(k 2(3 rd ) /T) -10.0 -10.5 -11.0
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SpinWorks 2.5: 2,6 pznClO4 in D2O N
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Table of Contents-5 Chapter 5 .....
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List of Tables Table 5.1: A summary
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5.1 Introduction Multinuclear plati
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onding. For this reason, pKa titrat
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400-300 cm -1): 3308, 3117, 3071 (N
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5.2.6 Spectrophotometric pKa Titrat
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Table 5.1: A summary of DFT-calcula
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However, because the highest occupi
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Table 5.2: Acid dissociation consta
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Table 5.3: A summary of DFT calcula
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H3N 6 eq TU 0 eq TU Ha NH3 Ha Cl TU
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third step due to the trans-effect
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[H 2 O-Pt-(NN)-Pt-OH 2 ] +4 [NU-Pt-
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k obs(1st) / s -1 0.20 TU DMTU TMTU
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thiourea nucleophile is large enoug
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ln(k st 2(1 ) /T) -3 -4 -5 -6 -7 -8
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is the same as the electron-withdra
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associative mode of substitution me
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16 H. Ertürk, J. Maigut, R. Puchta
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43 (a) D. Jaganyi, A. Hofmann and R
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276 nm Absorbance 0 . 6 5 0 . 6 4 0
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k obs(1 st ) , s -1 0.4 0.3 0.2 0.1
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ln(k 2(2 nd ) /T) -8.0 TU -8.5 -9.0
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pzn PPM -1750.0 -1850.0 -1950.0 -20
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Figure S5.13: UV/Visible spectra fo
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k obs(1 st ) in s -1 0.030 0.025 0.
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ln(k 2(2 nd ) /T) -10 -11 -12 -13 -
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9.61 ppm Ha PPM 9.8 9.6 9.4 9.2 9.0
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k obs(3rd) / s -1 -5 8 .00 x 10 T U
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ln(k st 2(1 ) /T) -1.5 TU DMTU TMTU
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ln(k rd 2(3 ) /T) -8.5 -9.0 -9.5 -1
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SpinWorks 2.5: znPt(II)-OP4 in D2O
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Figure S5.31: Mass spectrum for com
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ln(k st 2(1 ) /T) -4 -5 -6 -7 -8 -9
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SpinWorks 2.5: phtPt(II)-OP2 in D2O
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Figure S5.41: Mass spectrum for com
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List of Figures Figure 6.1: Spectro
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Chapter 6 Tuning Reactivity of Plat
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Against this background, several re
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6.2.2 Instruments Microanalyses wer
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Metal Complex Pt3 Yield: 52.5 mg (0
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6.3 Results 6.3.1 Synthesis and Cha
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The pKa values obtained are summari
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Table 6.2: DFT-calculated parameter
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that of dinuclear Pt(II) complexes
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It can be concluded that substituti
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ate constants, kobs(1 st /2 nd ), w
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Table 6.3: Summary of rate constant
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6.3.6 Activation Parameters The act
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pKa1 values become smaller. In addi
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of steric influence is felt by the
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6.5 Conclusion The present study ha
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17 O. F. Wendt and L. I. Elding, 19
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51 Y. Iwadata, K. Kawamura, K. Igar
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Table S6.4(b): Average observed rat
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ln(k 2(2 nd ) /T) -4 -6 -8 -10 -12
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45.0 40 35 30 25 20 %T 15 10 5 0 -5
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k st obs(1 ) in s-1 0.30 Br TU 0.25
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-2304.16 ppm H 3N PPM -2200.0 -2220
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Absorbance 1.6 1.4 1.2 1.0 0.8 0.6
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SH N SH + Mechanism Br N + CO 3 2-
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Figure 7.5: 195Pt NMR spectra of mi
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linker remained coordinated to the
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complexes, have a lower charge and
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ange 326-400 cm -1 (weak) for Pt-Cl
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ButPt, HexPt, OctPt and DecPt, were
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7.3 Results 7.3.1 DFT Calculations
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Structure HOMO LUMO EnPt (C2h) Prop
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Absorbance Table 7.2: Summary of pK
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coordination to the soft Pt(II) cen
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observed at -2962.4 and -3024.1 ppm
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H 3N NH 3 Pt NH 2 OH 2 n NH 3 NH 2
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k obs2 , in s -1 -3 TU 1.2x10 DMTU
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7.3.4 Activation Parameters The tem
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density is located on the metal cen
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acetylmethionine, which reported th
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References 1 (a) B. Rosenberg, L. V
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32 N. Summa, J. Maigut, R. Puchta a
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Appendix 7 Table S7.1: Summary of s
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k obs(2 nd ) , in s -1 0.00020 0.00
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ln(k 2(2 nd ) /T) -8.5 -9.0 -9.5 -1
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k obs(1 st ) , in s -1 0.06 TU DMTU
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ln(k 2(1 st ) /T) -3.2 TU DMTU TMTU
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Table S7.11: Summary of kobs(2 nd )
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%T 22.0 20 18 16 14 12 10 8 6 4 2 0
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k st obs(1 ) , in s-1 0.10 0.08 0.0
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ln(k st 2(1 ) /T) -4.0 TU DMTU TMTU
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Figure S7.23: Mass spectra for HexP
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Table S21: Average observed rate co
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Table S7.23: Summary of kobs(2 nd )
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90.0 80 70 60 50 40 30 20 %T 10 0 -
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Figure S7.37: Mass spectrum for Hex
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Chapter 8 Tuning Reactivity of plat
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dinuclear Pt(II) complexes to relea
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finally Pt2. The order of reactivit
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• prolonged survival in the cell
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Tuning Reactivity of Platinum(II) Complexes

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