Macrocyclic nickel(II) complexes: Spectroscopic studies and crystal structure of bis(difluoroboron-alpha-furilglyoximato)nickel(II)

Abstract Bis (difluoroboron - α - furilglyoximato) nickel (II), C 20 H 12 O 8 N 4 B 2 F 4 Ni, was prepared by cyclization of its hydrogen-bonded precursor with BF 3 ·OEt 2 . The compound crystallizes in the space group P 2 1 / c with a = 11.162(2), b = 5.569(2), c = 19.527(3) A, β = 100.08(1)°, U = 1195.1(3) A 3 , and Z = 2. The structure was refined to an R value of 0.033 using 2371 unique reflections collected with a CAD4-SDP diffractometer system. Unlike the corresponding planar macrocyclic as well as hydrogen-bonded dimethylglyoximates, the title compound neither dimerizes not exhibits columnar stacked structure. The 14-member macrocycle is planar except the B atoms, and no metal-metal interactions are observed in this compound. The complexation and cyclization reactions were investigated using spectral data. The structure is compared with other macrocyclic complexes.