Crystal Structures and Magnetic Properties of Nickel Complexes with Hydrotris(pyrazolyl)borate Ligand and Double Bridged by Phosphate Esters

Oxyphosphoranes as precursors to bridging phosphate-catecholate ligands

Examples of chelating ligands that incorporate P-O donors are seldom encountered. Herein, a series of novel bridging diphosphate ligand supported bimetallic Zr(iv), V(iii) and Ni(ii) complexes have been derived from reactions of the oxyphosphorane (C6Cl4O2)P(OEt)3 with the corresponding metal halides. The mechanism is probed and shown to involve elimination of ethyl halide, and ring opening affording the chelating phosphate-catecholate ligands.

Blocking and bridging ligands direct the structure and magnetic properties of dimers of pentacoordinate nickel(II)

Dinuclear pentacoordinate nickel(ii) complexes of the formula [(NiTp*)2(μ-L)] (Tp* = hydrotris(3,5-dimethylpyrazolyl)borate; L = oxalate (); oxamate (); oxamidate (); OC(4-Cl-C6H4N)C(4-Cl-C6H4N)O ()) and {[Ni(N3-mc)]2(μ-L)}(PF6)2 (N3-mc = 2,4,4-trimethyl-1,5,9-triazacyclododec-1-ene; L = oxalate (); oxamate ()) have been synthesized and spectroscopically characterized (IR, (1)H NMR). X-ray structures of show nickel(ii) in a square pyramidal geometry and different supramolecular interactions. Magnetic measurements for show strong antiferromagnetic interactions across the bridging ligand [: J = -36.8 cm(-1), g = 2.16; : J = -43.6 cm(-1), g = 2.12; : J = -51.1 cm(-1), g = 2.12; : J = -39.7 cm(-1), g = 2.18; : J = -35.4 cm(-1), g = 2.20; : J = -44.3 cm(-1), g = 2.18]. Magneto-structural correlations between the magnitude of the magnetic coupling and the different blocking ligands, the different bridging ligands, the distortion of the coordination environment of Ni(ii) and the planarity between the bridging ligand and the basal plane of the Ni(ii) environment have been established for all complexes.