Tuning Reactivity of Platinum(II) Complexes

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7.3 Results 7.3.1 DFT Calculations The optimised structures are given in Figure 7.1 and a complete list of the calculated results, including the Natural atomic Bond Order (NBO) charges, bond lengths and angles is recorded in Table 7.1. The data shows that the d 8 Pt(II) centre adopts a distorted square planar coordination geometry with an average bite angle, trans OH2– Pt–NH3, of 178 °C and cis H2O–Pt–NH2diamine of 84.2 °C. In addition, the “even” complexes EnPt, ButPt, HexPt, OctPt and DecPt adopt C2h symmetry, while a C2v symmetry is adopted for PropPt. It is seen from the data in Table 7.1 and Figure 7.3 that the energies of HOMO and LUMO frontier orbitals increase proportionately with the length of the aliphatic chain, whereas ΔE values follow the order EnPt < PropPt < ButPt < HexPt > OctPt > DecPt. This trend is a result of the differential σ-donation of electron density towards the Pt(II) centre created by the introduction of the alkanediamine bridge. The σ-donation of electron density increases with increasing HOMO and LUMO orbital energy levels, while its σ- inductive effect towards the Pt(II) atoms lessens on increasing the chain length of the aliphatic bridge further. The overall effect of increasing the alkanediamine chain is that the HOMO–LUMO energy gap increases to a maximum at HexPt before it starts to decrease with respect to OctPt and DecPt. A similar trend is observed when looking at rate of reduction of the NBO charges. The results indicate that after the (CH2)n group (n = 6), the interaction between the two Pt(II) centres decreases significantly which, in turn, is accompanied by a decrease in electrophilicity of the metal centre. 10
Table 7.1: Summary of selected DFT-calculated NBO charges, HOMO-LUMO energy gaps, bond lengths and angles of the studied Pt(II) complexes. N H 3 N H 3 H b c d a N Pt 2 a 2 Pt N 1 1 d c b H 2 O H EnPt PropPt ButPt HexPt OctPt DecPt MO energy/ eV HOMO -19.50 -18.98 -18.55 -17.89 -16.98 -15.81 LUMO -14.47 -13.86 -13.38 -12.68 -12.21 -11.88 ΔE/eV Bond length (Å) 5.03 5.12 5.17 5.21 4.77 3.93 Pt---Pt 7.797 9.040 10.302 12.824 15.349 17.890 Pt–Namine 2.168 2.143 2.132 2.115 2.107 2.104 Pt–OH2 Bond angles (°) 2.134 2.132 2.130 2.129 2.129 2.129 Namine–Pt–NH3 176.3 175.3 175.8 176.2 176.5 176.6 H2O–Pt–NH3 177.8 178.1 178.0 177.7 177.3 176.3 a 94.1 95.3 94.5 93.9 93.3 91.5 b 85.4 83.5 84.0 84.1 84.2 91.1 c 91.7 92.1 92.1 92.3 92.4 84.6 d NBO charges 88.8 88.9 89.3 89.8 90.1 91.8 Pt1/Pt2 1.1925 1.1924 1.1909 1.1888 1.1860 1.1850 Symmetry C2h C2v C2h C2h C2h C2h 11 H H H 2 O N H 3 N H 3
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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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Page 320 and 321: Table 6.3: Summary of rate constant
Page 322 and 323: 6.3.6 Activation Parameters The act
Page 324 and 325: pKa1 values become smaller. In addi
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Page 328 and 329: 6.5 Conclusion The present study ha
Page 330 and 331: 17 O. F. Wendt and L. I. Elding, 19
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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
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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
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Page 364 and 365: ButPt, HexPt, OctPt and DecPt, were
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
Page 380 and 381: 7.3.4 Activation Parameters The tem
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Page 384 and 385: acetylmethionine, which reported th
Page 386 and 387: References 1 (a) B. Rosenberg, L. V
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 )
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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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