The X-ray crystallographic structures, spectral and magnetic properties of nickel(II), copper(II) and cobalt(II) complexes with tetra(3- iso-propylpyrazol-1-yl)borate

Abstract

Tetra(3- iso-propylpyrazol-1-yl)borate ligand (L) forms mono-ligand LMX and bis-ligand L 2M complexes (where M=Ni(II), and Cu(II), and X=Cl − or NO 3 − ) depending on the stoichiometry of the synthesis, while a polynuclear (NCS) 2Co(L)Co(L)Co(NCS) 2 complex is obtained when excess of cobalt(II) thiocyanate is used. The L coordinates to metal ions in a κ 3 fashion in LNiCl, LNi(NO 3)(5- i PrpzH) and LCuCl(5- i PrpzH), whereas a κ 2 binding mode was found in L 2Ni and in unique (NCS) 2Co(L)Co(L)Co(NCS) 2, in which L bridges two metal ions.