Coordination of 6-Methyl-2,2'-bipyridine. Structure of Bivalent Copper and Palladium Complexes

Bis ( ligand ) complexes of 6-methyl-2,2'-bipyridine (L) with copper(II) and palladium(II) have been prepared, and their structures have been determined by single-crystal X-ray diffractometry . In the formation of the complex fromcopper(II) tetrafluoroborate and L, partial hydrolysis of a coordinated fluoroborate ion to the hydroxytrifluoroborate ion occurs. The stereochemistry about copper in [CuL2OHBF3][BF4] is essentially trigonal bipyramidal with an axial compression. The nitrogens of the methyl-substituted pyridine rings coordinate in the axial sites. In [PdL2Cl][BF4] the coordination environment about palladium is square planar and one of the 6-methylbipyridine molecules functions as a unidentate group, the nitrogen of the methyl-substituted pyridine ring being uncoordinated. The average metal-nitrogen distance is 2.032 ? in the copper complex and 2.042 ? in the palladium complex. [CuL2OHBF3][BF4] is monoclinic, space group P21/c, Z = 4, a 9.005(2), b 17.868(2), c 15.298(3) ?, ß 104.13(1)°. [PdL2Cl][BF4] is monoclinic, space group P21/c, Z = 4, a 9.606(5), b 14.748(2), c 16.311(8)?, ß 96.13(2)°.