Structural Chemistry of Necessarily Distorted Bis(Bipyridine) Complexes. The Crystal Structure of the Trans-[Bis(2,2'-Bipyridine)Bis(Triphenul-Phosphine)Ruthenium(II)] and Trans-[Bis(4,4'-Dimethyl-2,2'-Bipyridine)Bis(Pyridine)Ruthenium(ii)] Cations

Abstract

The cation trans-[Ru(bpy)2(PPh3)2]2+ and trans-[Ru(Me2bpy2)2(py)2]2+ both contain bipyridine ligands which are distorted because of the crowding of the two chelate units. The hexafluorophosphate salt of the first cation crystallizers in space group P21/n, with a = 11.630(1), b = 20.245(2), c = 11.299(1)Å, &#x03B2 = 103.99(1)°, and Z = 2. R = 0.047 for 2396 observed reflections. The hexafluorophosphate salt of the second cation crystallizers in space group C2/m, with a = 18.392(2), b = 11.265(1), c = 13.383(1)Å, &#x03B2 = 139.42(2)°, and Z = 2. R = 0.047 for 1403 observed reflections. The Ru of the first cation lies on an inversion center and the Ru of the second cation lies on a special position of 2/m symmetry. The distortions of a number of bipyridine complexes with the trans geometry are analyzed and found to fall into two categories, bowed or twisted. The two complexes of this report were found to have a bowed conformation