Structure and Magnetic Properties of Bis(mu-azido) bis [N,N '-bis(2-pyridylmethyl) ethylenediamine] dinickel (II) complex

A binuclear nickel( II) complex of [Ni-2 (bispicen)(2) (mu- N-3)(2)] (ClO4) (2) [bispicen= N, N' - bis (2-pyridylmethyl) ethylenediamine] has been synt hesized and characterized by means of elemental analysis, IR and electronic spectra. The crystal structure was determined by single - crystal X - ray diffraction technology. The complex crystallizes in orthorhombic space grou p P2(1)2(1)2(1). The nickel( II) ion resides in a pseudo - octahedral envir onment with a cis - alpha configuration. The azido ligand bridges two Ni(II ) ions in the mu- 1,3 (end - to - end) mode, and unlike most polynuclear co mplexes with double mu - 1, 3 - N-3 bridges, where the (N3)2 bridging moiet y forms a plane, the two azido bridges in the present complex are non - cop lanar and crossed at an angle of 49.7 degrees. The temperature dependence o f the magnetic susceptibility of the complex has been investigated and reve aled an antiferromagnetic interaction between the two Ni( II) ions with the exchange integral J = -28.1 cm(-1) (based on (H) over cap = - 2J (S) over cap (1)(S) over cap (2)).