Heterobimetallic chemistry: Heterobimetallic complexes derived from monometallic copper(II) complex of bis(2-hydroxy-l-naphthaldehyde)malonoyldihydrazone

Abstract

Monometallic copper(II) complex [Cu(LH₂)(H₂O)₂] (<b>1</b>) and heterobimetallic complexes [MCu(L)(H₂O)₃] (where M = UO₂(2) and Zn(4)) and [MCu(L)(H₂O)4] (where M = MoO₂(3), Ni(5), Co(6) and Mn(7)) and homobimetallic copper(II) complex [Cu₂(L)(H₂O)₄].2H₂O(8) have been isolated and characterized by analytical, molecular weight, magnetic moment, electrical conductance, electronic IR and ESR spectral data. IR spectral evidences indicate that dihydrazone coordinates to the metal centres in enol forms. The monometallic copper(II) complex (<b>1</b>) and the heterobimetallic complexes UO₂Cu (2) and MoO₂Cu (3) and Zn-Cu (4) are normal paramagnetic indicating absence of any metal-metal interaction in the structural unit of the complexes while the remaining heterobimetallic complexes Ni-Cu(5), Co-Cu (6) and Mn-Cu (7) have much less μ_eff values than those required for 3, 4 and 6 unpaired electrons indicating considerable metal-metal interactions. Copper has distorted octahedral geometry in monometallic and heterobimetallic complexes. Uranium has pentagonal bipyramidal stereochemistry while zinc has square pyramidal stereochemistry. However, copper(II) has square pyramidal stereochemistry in homobimetallic complex (8).