Structure, physical and photophysical properties of platinum(II) complexes containing 7,8-benzoquinoline and various bis(diphenylphosphine) ligands

Article abstract of DOI:10.1016/s0020-1693(97)05688-0

A series of platinum complexes, [Pt(7,8-bzq)(dppm)] (PF₆), [Pt(7,8-bzq)(dppe)] (PF₆) and [Pt(7,8-bzq)(dppp)] (PF₆), which vary only in the number of carbon atoms bridging two diphenyl phosphine ligands, have been synthesized and their structures have been determined by single crystal X-ray crystallography. Structural characteristics are as follows: [Pt(7,8-bzq)(dppm)] (PF₆), orthorhombic, Pbca, a = 17.427(4), b = 17.946(4), c = 22.262 ?, Z=8; [Pt(7,8-bzq)(dppe)] (PF₆), monoclinic, P2₁/c, a = 11.519(2), b = 14.080(3), c = 21.804(4) ?, Z=4; [Pt(7,8-bzq)(dppp)] (PF₆), Pna2₁, a = 20.216(4), b = 11.574(2), c = 15.739(3) ?, Z=4. The P-Pt-P bite angle varies in the series from 72.1 (5) to 84.5(2) to 91.57(10)° 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 at 77 K increase in the same order. Emission lifetime differences are shown to relate to the perturbation associated with the additional methylene groups.