Novel Dinuclear Copper(II) Complexes with syn–syn and syn–anti Coordination Modes of Bis ((mu)-phosphinato)-bridges: Structures and Magnetic Properties

Novel dinuclear copper(II) complexes with phosphinato bridging ligands, [Cu2(NO3)(bmp)2(5-dmbpy)2]NO3·H2O (1), [Cu2 (bmp)2(5-dmbpy)2(MeOH)2](BF4)2 (2) (Hbmp = bis(4-methoxyphenyl)phosphinic acid, 5-dmbpy = 5,5ʹ-dimethyl-2,2ʹbipyridine), have been prepared and characterized. Crystal structures of 1 and 2 have revealed that two copper(II) ions in 1 are linked by two syn–syn bridging phosphinates, whereas 2 has two syn–anti bridging phosphinates. Magnetic susceptibility data for the present complexes are well represented by the dimer equation with the 2J values of -19.1 cm^-1 for 1 and -0.7 cm^-1 for 2, indicating that weak antiferromagnetic interactions are operative.