Synthesis and photophysical properties of luminescent platinum(II) complexes with terdentate polypyridine ligands:: [Pt(bpqb)X] and [Pt(tbbpqpy)X](PF6) (bpqb-H=1,3-bis(4'-phenyl-2'-quinolinyl) benzene;tbbpqpy=4-tert-butyl-1,3-bis(4'-phenyl-2'-quinolinyl) pyridine;: X=Cl, CCC6H5,, CCC6H4NMe2, CCC6H4NO2)

A series of square planar platinum(II) complexes, [Pt(bpqb)X] (X=Cl (1), C=CC6H5 (2), C=CC6H4NMe2-4 (3), C CC6H4NO2-4 (4)), [Pt(tbbpqpy)X](PF6) (X=Cl (5), C CC6H5 (6), C=CC6H4NMe2-4 (7), C CC6H4NO2-4 (8)), bearing terdentate polypyridine ligands have been prepared. Their electronic absorption spectra and emission characteristics at room temperature have been investigated. These complexes display room temperature photoluminescence. The emission energies are sensitive to the nature of the acetylide ligands with different substituents on the phenyl ring. An emission origin of a d pi(Pt) -> pi*(bpqb or tbbpqpy) (MLCT)-M-3 excited state, with some mixing of a pi(C equivalent to CR) -> pi*(bpqb or tbbpqpy)(LLCT)-L-3 state, is assigned. All the complexes display two quasi-reversible reduction couples and one irreversible oxidation wave in the cyclic voltammograms. The reactivity of [Pt(bpqb)Cl] with pi-acceptor ligands and the X-ray crystal structures of tbbpqpy, 1, and [Pt(bpqb)(PEt3)(2)CI] (9) are also described. (c) 2006 Elsevier B.V. All rights reserved.