Tuning Reactivity of Platinum(II) Complexes

adjusted by addition of 0.01 M LiCl to prevent spontaneous solvolysis. The ionic strength
of the solution was maintained using lithium trifluoromethanesulfonate (LiCF3SO3)
−
because the triflate ion, ( CF ), does not coordinate to Pt(II) in solution.22,,23
3 3 SO
Similarly, stock solutions of the metal complexes (ca. 10 -5 mol dm -3 ) were prepared
using 0.1 M LiCF3SO3 solution.
3.2.1.1 Synthesis of the ligands and complexes
The platinum complexes, [Pt{4’-(2"'-CH3-phenyl)-2,2’:6’,2’’-terpyridine}Cl]CF3SO3
CH3PhPtCl and [Pt{4’-(2"'-CH3-phenyl)-6-(3’’-isoquinoyl)-2,2’-bipyridine}Cl]SbF6
CH3PhisoqPtCl were synthesised and characterised using literature methods. 18,24
Details of the synthesis and characterisation of CH3PhPtCl and CH3PhisoqPtCl have been
reported previously by Field 19 and our group. 20 The complex, [Pt{2-(2’-pyridyl)-1,10-
phenanthroline}Cl]Cl, pyPhenPtCl, was a donation from McMillin and co-workers 21
(University of Purdue, West Lafayette, Indiana, USA).
3.2.1.2 Synthesis of [Pt{2–(2’–pyridyl)–1,10–phenanthroline}Cl]Cl
Synthesis of pyphen ligand
The synthesis of the 2-(2’-pyridyl)-1,10-phenanthroline (pyphen) ligand 21 for the
preparation of the complex pyPhenPtCl is illustrated in Scheme 3.2.
N
Br
+
N
phen
N
-HBr
THF, -78 o C
Scheme 3.2: Preparation pathway for pyphen ligand
4
N
N
pyphen
To a solution of 2-bromopyridine in dry tetrahydrofuran (THF) was added
stoichiometric amount of n-butyllithium at -78 °C, under argon atmosphere. A red
solution resulted. After stirring for 15 min, 1.2 equiv. of the n-butyllithium reagent
(mixture) was transferred, via a cannula, to a solution of 1,10-phenanthroline in dry THF
at -78 °C also under Ar to produce a deep red solution. The mixture was stirred for 2 h,
N