Ground and excited state structural isomers in trans-[Ru(bpy)2(L)2](PF6)2

Spectroscopic evidence is presented for different structural isomers of trans-[Ru(bpy)(2)(L-1)(L-1)](2+) (L-1 or L-2 = 4-Etpy (1), py-PTZ) in which bpy is planar or nonplanar compared to cis-[Ru(bpy)(2)(py)(2)](2+) or [Ru(bpy)(3)](2+) in which bpy is planar. The nonplanar form is dominant in the ground states in low temperature glasses. The two forms appear to be in a temperature dependent equilibrium in 4:1 (v/v) ethanol/methanol at higher temperatures. The nonplanar form is converted into the planar form in the MLCT excited state(s) of 1. (C) 2000 Elsevier Science B.V. All rights reserved.