STRUCTURE, PHYSICAL AND PHOTOPHYSICAL PROPERTIES OF PLATINUM(II) COMPLEXES CONTAINING 7,8-BENZOQUINOLINE AND VARIOUS BIS(DIPHENYLPHOSPHINE)LIGANDS

A series of platinum complexes, [Pt(7,8-bzq)(dppm)](PF6), [Pt(7,8-bzq) (dppe)](PF6) and [Pt(7,8-bzy)(dppp)](PF6), which vary only in the numb er of carbon atoms bridging two diphenyl phosphine ligands, have been synthesized and their structures have been determined by single crysta l X-ray crystallography. Structural characteristics are as follows: [P t(7,8-bzq)(dppm)](PF6), orthorhombic, Pbca, a = 17.427(4), b = 17.946( 4), c = 22.262 Angstrom, Z = 8; [Pt(7,8-bzq)(dppe)](PF6), monoclinic, P2(1)/c, a = 11.519(2), b = 14.080(3), c = 21.804(4) Angstrom, Z = 4; [Pt(7,8-bzq)(dppp)](PFepsilon), Pna2(1), a = 20.216(4), b = 11.574(2), c = 15.739(3) Angstrom, Z = 4. The P-Pt-P bite angle varies in the se ries from 72.1(5) to 84.5(2) to 91.57(10)degrees for [Pt(7,8-bzq)(dppm )](+), [Pt(7,8-bzq)(dppe)](+) and [Pt(7,8-bzq)(dppp)](+), respectively . The absorption spectra are blue-shifted and the emission lifetimes a t 77 K increase in the same order. Emission lifetime differences are s hown to relate to the perturbation associated with the additional meth ylene groups. (C) 1997 Elsevier Science S.A.