Tuning Reactivity of Platinum(II) Complexes

PhCN
PhCN
Pt
Cl
Cl
+
N
N
CH 3
N
CH 3 CN
40-50 o C
[Pt(PhCN) 2 Cl 2 ] [4'-(2"'-CH 3 -Ph)-2,2': 6',2"-terpy] CH 3 PhPtCl
Scheme 3.9: Synthesis of the complex CH3PhPtCl
11
N
N
Pt
Cl
CH 3
N
CF 3 SO 3
To a solution of 1.0 mol of [Pt(PhCN)2Cl2] in acetonitrile was added slowly and with
constant stirring an equimolar amount of AgCF3SO3. The contents were refluxed for 16 h
under nitrogen. The precipitated AgCl was filtered off, and one equiv. of 4’–(2’’’–CH3–
phenyl)–2,2’:6’,2’’–terpyridine ligand was added to the filtrate and refluxed for a
further 24 h. The solution was allowed to cool down, which resulted in the separation of
a red solid that was filtered, washed with small amounts of diethyl ether, acetonitrile
and dried in vacuo. The required product, [CH3PhPtCl], was characterised by elemental
analysis, IR (KBr disc), 1H and 13C NMR and UV-Vis spectroscopy. 18 [CH3PhPtCl]: Anal.
Calcd for C23H17ClF3N3PtS: C, 39.24; H, 2.58; N, 5.97. Found: C, 38.96; H, 2.94; N, 5.68%.
3.2.2 Physical Measurements and Instrumentation
Kinetic Analyses
All kinetic measurements were performed under pseudo first-order conditions using at
least a 10-fold excess of the entering nucleophile. The wavelengths chosen for the kinetic
investigations were determined from UV/Visible absorption spectra obtained from
measurements on a Varian Cary 100 Bio UV/Visible spectrophotometer. The
wavelengths at which there was greatest absorbance change were used for the
subsequent kinetic analyses. These are summarised in Table SI 3.1 (appendix). An
Applied Photophysics SX.18MV (v 4.33) stopped-flow analyzer coupled to an online data
acquisition system was used to determine the observed rate constants, kobs. All
measurements were carried out in a thermostated environment to within ± 0.1 o C using