SYNTHESIS AND CHARACTERIZATION OF TETRANUCLEAR COPPER@) COMPLEXES BY CONTINUED COMPLEXATION OF A NEW CLASS OF BINUCLEATING LIGAND 3,3’-DIMETHOXY-4,4’- BIS(l-ALKYL(R)TRIAZENE-l-0XIDE)BIPHENYL

Abstract

A new class of binuclear copper(I1) complexes, CuZL2, yielded a series of tetra- nuclear copper(I1) complexes, Cu2L2(CuA&, when mixed with CuA2 in a 1 : 2 molar ratio (where LH2 = 3,3’-dimethoxy-4,4’-bis(l-alkyl(R)triazene-l-oxide)biphenyl R-triaz-bp-OCH, and A = Cl, Br). No appreciable antiferromagnetic denoted interaction was observed between any two sets of copper(I1) centres as suggested by magnetochemical or ESR studies. The optical spectra suggest that the two sets of copper(I1) centres have different geometries, the Cu2L2 based coppers are near square-planar while the CuA, based ones are near tetrahedral. The reason for the absence of magnetic interaction between any two copper(I1) centres is discussed in the light of the structure of the complexes.