Tuning Reactivity of Platinum(II) Complexes
Tuning Reactivity of Platinum(II) Complexes Tuning Reactivity of Platinum(II) Complexes
Table 6.3: Summary of rate constants and activation parameters with the corresponding standard deviations for the substitution of aqua ligands by neutral (TU, DMTU, and TMTU) and ionic (I ¯ , Br ¯ and SCN ¯ ) nucleophiles, I = 0.10 M (NaClO4). Complex NU k2,1 st / M -1 s -1 Δ ≠H1 st /kJmol -1 Δ ≠S1 st /J mol -1 K -1 Pt1 NH3 Pt N NH3 H O 2 S N H 2 O 4+ NH 3 Pt NH3 NH3 Pt2 1 Pt3 OH 2 H3N Pt N NH 3 H 2 O Pt N NH 3 S S N NH 3 Pt NH 3 OH 2 4+ NH 3 N Pt H 2 O NH 3 4+ TU 33.5 ± 0.5 63 ± 1.4 -41 ± 4.6 DMTU 25.9 ± 1.1 56± 1.5 -64 ± 5.0 TMTU 6.4 ± 0.1 58 ± 2.5 -57 ± 8.3 SCN¯ 14.0 ± 0.6 60 ± 4.9 -52 ± 16.3 Br¯ 0.4 ± 0.01 73 ± 2.3 -26 ± 7.5 TU 244.6 ± 2.9 53 ± 0.4 -52 ± 1.4 DMTU 179.0 ± 2.8 48 ± 2.8 -111 ± 9.3 TMTU 86.2 ± 1.8 48 ± 1.6 -91 ± 5.4 SCN¯ 542.0 ± 14.1 69 ± 1.0 -26 ± 3.4 Br¯ 13.0 ± 0.2 74 ± 2.3 -25 ± 7.7 TU 129.5 ± 1.6 53 ± 0.4 -53 ± 1.3 DMTU 65.6 ± 0.6 44 ± 1.6 -85 ± 5.5 TMTU 13.4 ± 0.2 41 ± 0.5 -112 ± 1.8 SCN¯ 258.2 ± 2.5 54 ± 3.0 -39 ± 10.0 I¯ 129.5 ± 1.6 42 ± 1.7 -83 ± 5.6 Br¯ 11.8 ± 0.2 50 ± 2.0 -104 ± 6.6 At pH 2.0, the S–S bond scission occurred reversibly in a redox reaction with iodide: py–S–S-py + 2I ¯ ↔ 2py–S ¯ + I2. This limited further kinetic studies for Pt1 and Pt2 complexes. 21
Table 6.4: Summary of rate constants and activation parameters with the corresponding standard deviations for the release of bridging ligand by neutral (TU, DMTU, and TMTU) and ionic (I ¯ , Br ¯ and SCN ¯ ) nucleophiles, I = 0.10 M (NaClO4). Complex NU k2,2 nd / 10 -3 M -1 s -1 ΔH ≠ 2 nd /kJ mol -1 ΔS ≠ 2 nd /J mol -1 K -1 Pt1 TU 102.1 ± 0.20 49 ± 3.2 -107 ± 10.7 DMTU 51.5 ± 0.64 53 ± 0.6 -99 ± 1.9 TMTU 70.6 ± 1.52 48 ± 1.9 -117 ± 6.4 SCN ¯ 39.0 ± 0.28 65 ± 1.7 -61 ± 5.8 Pt2 TU 35.4 ± 0.23 53 ± 1.3 -95 ± 4.5 DMTU 14.3 ± 0.05 62 ± 1.1 -73 ± 3.6 TMTU 24.9 ± 0.12 49 ± 0.9 -116 ± 2.9 SCN ¯ 18.8 ± 0.41 49 ± 1.0 -83 ± 3.5 Pt3 TU 23.8 ± 0.18 59 ± 1.2 -80 ± 4.1 DMTU 7.6 ± 0.36 49 ± 1.2 -122 ± 4.1 TMTU 1.4 ± 0.22 50 ± 1.1 -133 ± 3.6 SCN¯ 14.7 ± 0.14 49 ± 1.1 -78 ± 3.5 I ¯ 1.2 ± 0.14 50 ± 1.2 -133 ± 3.9 Br ¯ = No reaction was observed in the second step in all cases. None of the plots exhibited an intercept in all the reactions of the complexes with the nucleophiles, indicating that both steps are irreversible in nature, and k-1 and k-2 are zero since the reverse reaction is too slow, if it exists. Thus, the rate equations for the two substitution reaction steps can be expressed by Equation 1. kobs(1 st /2 nd ) = k2(1 st /2 nd)[NU] (1) 22
- Page 270 and 271: Table S5.17: Average observed rate
- Page 272 and 273: ln(k 2(2 nd ) /T) -10 -11 -12 -13 -
- Page 274 and 275: 9.61 ppm Ha PPM 9.8 9.6 9.4 9.2 9.0
- Page 276 and 277: Table S5.22: Average observed rate
- Page 278 and 279: k obs(3rd) / s -1 -5 8 .00 x 10 T U
- Page 280 and 281: ln(k st 2(1 ) /T) -1.5 TU DMTU TMTU
- Page 282 and 283: ln(k rd 2(3 ) /T) -8.5 -9.0 -9.5 -1
- Page 284 and 285: SpinWorks 2.5: znPt(II)-OP4 in D2O
- Page 286 and 287: Figure S5.31: Mass spectrum for com
- Page 288 and 289: Table S5.28: Average observed rate
- Page 290 and 291: Table S5.29: Average observed rate
- Page 292 and 293: ln(k st 2(1 ) /T) -4 -5 -6 -7 -8 -9
- Page 294 and 295: SpinWorks 2.5: phtPt(II)-OP2 in D2O
- Page 296 and 297: Figure S5.41: Mass spectrum for com
- Page 298 and 299: List of Figures Figure 6.1: Spectro
- Page 300 and 301: Chapter 6 Tuning Reactivity of Plat
- Page 302 and 303: Against this background, several re
- Page 304 and 305: 6.2.2 Instruments Microanalyses wer
- Page 306 and 307: Metal Complex Pt3 Yield: 52.5 mg (0
- Page 308 and 309: 6.3 Results 6.3.1 Synthesis and Cha
- Page 310 and 311: The pKa values obtained are summari
- Page 312 and 313: Table 6.2: DFT-calculated parameter
- Page 314 and 315: that of dinuclear Pt(II) complexes
- Page 316 and 317: It can be concluded that substituti
- Page 318 and 319: ate constants, kobs(1 st /2 nd ), w
- Page 322 and 323: 6.3.6 Activation Parameters The act
- Page 324 and 325: pKa1 values become smaller. In addi
- Page 326 and 327: of steric influence is felt by the
- Page 328 and 329: 6.5 Conclusion The present study ha
- Page 330 and 331: 17 O. F. Wendt and L. I. Elding, 19
- 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 350 and 351: Table S6.13: 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
- Page 358 and 359: linker remained coordinated to the
- 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
Table 6.3: Summary <strong>of</strong> rate constants and activation parameters with the<br />
corresponding standard deviations for the substitution <strong>of</strong> aqua ligands by<br />
neutral (TU, DMTU, and TMTU) and ionic (I ¯ , Br ¯ and SCN ¯ ) nucleophiles, I =<br />
0.10 M (NaClO4).<br />
Complex NU k2,1 st / M -1 s -1 Δ ≠H1 st /kJmol -1 Δ ≠S1 st /J mol -1 K -1<br />
Pt1<br />
NH3 Pt<br />
N<br />
NH3 H O 2<br />
S<br />
N<br />
H 2 O<br />
4+<br />
NH 3<br />
Pt NH3<br />
NH3 Pt2 1<br />
Pt3<br />
OH 2<br />
H3N Pt N<br />
NH 3<br />
H 2 O<br />
Pt N<br />
NH 3<br />
S<br />
S<br />
N<br />
NH 3<br />
Pt NH 3<br />
OH 2<br />
4+<br />
NH 3<br />
N Pt<br />
H 2 O<br />
NH 3<br />
4+<br />
TU 33.5 ± 0.5 63 ± 1.4 -41 ± 4.6<br />
DMTU 25.9 ± 1.1 56± 1.5 -64 ± 5.0<br />
TMTU 6.4 ± 0.1 58 ± 2.5 -57 ± 8.3<br />
SCN¯ 14.0 ± 0.6 60 ± 4.9 -52 ± 16.3<br />
Br¯ 0.4 ± 0.01 73 ± 2.3 -26 ± 7.5<br />
TU 244.6 ± 2.9 53 ± 0.4 -52 ± 1.4<br />
DMTU 179.0 ± 2.8 48 ± 2.8 -111 ± 9.3<br />
TMTU 86.2 ± 1.8 48 ± 1.6 -91 ± 5.4<br />
SCN¯ 542.0 ± 14.1 69 ± 1.0 -26 ± 3.4<br />
Br¯ 13.0 ± 0.2 74 ± 2.3 -25 ± 7.7<br />
TU 129.5 ± 1.6 53 ± 0.4 -53 ± 1.3<br />
DMTU 65.6 ± 0.6 44 ± 1.6 -85 ± 5.5<br />
TMTU 13.4 ± 0.2 41 ± 0.5 -112 ± 1.8<br />
SCN¯ 258.2 ± 2.5 54 ± 3.0 -39 ± 10.0<br />
I¯ 129.5 ± 1.6 42 ± 1.7 -83 ± 5.6<br />
Br¯ 11.8 ± 0.2 50 ± 2.0 -104 ± 6.6<br />
At pH 2.0, the S–S bond scission occurred reversibly in a redox reaction with iodide: py–S–S-py + 2I ¯ ↔<br />
2py–S ¯ + I2. This limited further kinetic studies for Pt1 and Pt2 complexes.<br />
21
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