Tuning Reactivity of Platinum(II) Complexes

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7.3.4 Activation Parameters The temperature dependence of the rate constant, k2, was studied over the range 15- 35°C in increments of 5 °C. Figures 7.9 & 7.10 (also Figures S7.3-S7.4, S7.8-S7.9, S7.13- S7.14, S7.19-S7.20, and S7.28-S7.29, for the corresponding complexes EnPt, PropPt, ButPt, HexPt and DecPt, Appendix 7) show the representative Eyring plots, for the reaction of OctPt with the different nucleophiles. The corresponding activation parameters ΔH ≠ and ΔS ≠ in Table 7.3, were calculated using the Eyring equation. ln(k 2(1 st ) /T) -3.5 -4.0 -4.5 -5.0 -5.5 -6.0 -6.5 -7.0 -7.5 0.00320 0.00325 0.00330 0.00335 0.00340 0.00345 0.00350 1/T, K -1 24 TU DMTU TMTU Figure 7.9: Eyring plots forthe determination of the activation enthalpies and entropies for k2,1st of all nucleophiles studied with OctPt complex.
ln(k 2(2nd) /T) -8 -9 -10 -11 -12 -13 0.00320 0.00325 0.00330 0.00335 0.00340 0.00345 0.00350 1/T, K -1 25 TU DMTU TMTU Figure 7.10: Eyring plots forthe determination of the activation enthalpies and entropies for k2,2 nd of all nucleophiles studied with OctPt complex . 7.4 Discussion 7.4.1 pKa of the Diaqua Complexes From previous studies, it has been reported that pKa values obtained for coordinated aqua ligand at the Pt(II) centre is a good indicator of the electrophilicity of the metal centre, 49 and therefore, of the reactivity of the aqua complex. The results in Table 7.2 indicate that the pKa values of the studied complexes increase as the number of (CH2)n groups of the alkanediamine bridge increases from n = 3 to 10. The slight increase in pKa values follows the order PropPt < ButPt < HexPt ≤ OctPt < DecPt. This order is due to the lengthening of the alkanediamine chain, which causes a decrease in localised charge on the Pt(II) centre, reducing electronic communication between the two Pt(II) centres as the separation distance is increased (see Table 7.1). A short distance between the Pt(II) centres in dinuclear Pt(II) complexes results in additional charge increases, which add to an overall of +4 at each Pt centre. 45 As a consequence of this higher charge, each Pt(II) centre becomes more electrophilic and more acidic, leading to lower pKa values for the coordinated water ligands. The effect of charge additions is more important when the distance between the Pt(II) centres is relatively shorter. 29,30,50 Secondly, the electron-releasing inductive effect of the alkanediamine linker means more electron
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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
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toxic potential. The most well-know
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1.3.2.2 Cellular Uptake Cisplatin i
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H 3N OH 2 Pt H 3N OH 2 Active Pt(II
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transformational pathways that comp
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the hydrolysis of the complex, wher
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1.3.4 Terpyridine Platinum(II) Comp
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H 3 N Cl Pt NH 3 H 3 N NH 2 (CH 2 )
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1.4 Kinetic Interest The platinum-b
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3. The effect of varying the positi
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17 R. A. Henderson, The Mechanism o
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Altona J. H. van Boom, G. A. van de
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76 (a)J. Kašpárková, J. Zehnulov
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Table of Contents-2 Chapter Two ...
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List of Tables Table 2.1: A selecti
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The mononuclear Pt(II) complexes 1-
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Potential Energy R + X RX 1 transit
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For the associative mechanism (A),
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the concentration of one of the rea
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k obs , s -1 0.00030 0.00025 0.0002
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k = Ae -Ea/RT 2.14 lnk = lnA - E a
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= 23.76 + R Hence, a plot of ln ⎛
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iii. # Δ V ≈ 10 cm3 mol-1 featur
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conventional methods are classical
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Figure 2.6: Schematic diagram of a
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The light transmitted from the samp
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c. Oxidizability: Ligands that are
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Table 2.1: A selection of n o pt va
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eaction with different nucleophiles
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eaction site from direct attack by
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PEt 3 PEt 3 R PEt 3 Pt Pt Y Y Cl R
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direct displacement of the leaving
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therefore, weaken the bond of the l
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σ-Donation According to classical
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References 1 (a) J. Reedijk, Chem.
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34 R. B. Jordan, Reaction Mechanism
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Table of Contents-3 Chapter 3.The
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Chapter 3 The π-Acceptor Effect in
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In order to extend our understandin
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after which water was added to quen
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O CH 3 + I + N O oH - N O O 7 CH 3
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84% (34.7 mg, 0.0618 mmol). 1 H NMR
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PhCN PhCN Pt Cl Cl + N N CH 3 N CH
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Complex Structure HOMO LUMO PtCl CH
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The geometry-optimised structures i
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against the concentration of the in
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Table 3.2: Summary of the second-or
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constants of CH3PhisoqPtCl decrease
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with π*-orbitals of the ligand. Th
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3.6 References 1 D. Rosenberg, L. V
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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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Page 332 and 333: 51 Y. Iwadata, K. Kawamura, K. Igar
Page 334 and 335: Table S6.3: Average observed rate c
Page 336 and 337: Table S6.4(b): Average observed rat
Page 338 and 339: ln(k 2(2 nd ) /T) -4 -6 -8 -10 -12
Page 340 and 341: 45.0 40 35 30 25 20 %T 15 10 5 0 -5
Page 342 and 343: k st obs(1 ) in s-1 0.30 Br TU 0.25
Page 344 and 345: Table S6.9: Average observed rate c
Page 346 and 347: -2304.16 ppm H 3N PPM -2200.0 -2220
Page 348 and 349: Table S6.10: Average observed rate
Page 352 and 353: Absorbance 1.6 1.4 1.2 1.0 0.8 0.6
Page 354 and 355: SH N SH + Mechanism Br N + CO 3 2-
Page 356 and 357: Figure 7.5: 195Pt NMR spectra of mi
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Page 360 and 361: complexes, have a lower charge and
Page 362 and 363: ange 326-400 cm -1 (weak) for Pt-Cl
Page 364 and 365: ButPt, HexPt, OctPt and DecPt, were
Page 366 and 367: 7.3 Results 7.3.1 DFT Calculations
Page 368 and 369: Structure HOMO LUMO EnPt (C2h) Prop
Page 370 and 371: Absorbance Table 7.2: Summary of pK
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Page 376 and 377: H 3N NH 3 Pt NH 2 OH 2 n NH 3 NH 2
Page 378 and 379: k obs2 , in s -1 -3 TU 1.2x10 DMTU
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Page 384 and 385: acetylmethionine, which reported th
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Page 388 and 389: 32 N. Summa, J. Maigut, R. Puchta a
Page 390 and 391: Appendix 7 Table S7.1: Summary of s
Page 392 and 393: k obs(2 nd ) , in s -1 0.00020 0.00
Page 394 and 395: ln(k 2(2 nd ) /T) -8.5 -9.0 -9.5 -1
Page 396 and 397: k obs(1 st ) , in s -1 0.06 TU DMTU
Page 398 and 399: ln(k 2(1 st ) /T) -3.2 TU DMTU TMTU
Page 400 and 401: Table S7.11: Summary of kobs(2 nd )
Page 404 and 405: %T 22.0 20 18 16 14 12 10 8 6 4 2 0
Page 406 and 407: k st obs(1 ) , in s-1 0.10 0.08 0.0
Page 408 and 409: ln(k st 2(1 ) /T) -4.0 TU DMTU TMTU
Page 410 and 411: Figure S7.23: Mass spectra for HexP
Page 412 and 413: Table S21: Average observed rate co
Page 414 and 415: Table S7.23: Summary of kobs(2 nd )
Page 418 and 419: 90.0 80 70 60 50 40 30 20 %T 10 0 -
Page 420 and 421: Figure S7.37: Mass spectrum for Hex
Page 422 and 423: Chapter 8 Tuning Reactivity of plat
Page 424 and 425: dinuclear Pt(II) complexes to relea
Page 426 and 427: finally Pt2. The order of reactivit
Page 428: • prolonged survival in the cell
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