Spectroscopic studies on isomerisation of coordinated polyfunctional dihydrazone in going from monometallic to bimetallic complexes: Zinc(II), copper(II) and dioxouranium(VI) complexes of bis(2-hydroxy-1-naphthaldehyde)oxaloyl-dihydrazone

The monometallic complexes of the type [Zn-2(H4L)(2) (SO4)(2)] (1), [Zn-2(H2L)(2)(H2O)(2)] (2), K-2[Zn-2(H2L)(2)F-2] (2a), and the heterobimetallic complexes of the type [(UO2)(2)Zn-2(L)(2)(H2O)(6)] (3), K-4[(UO2)(2)Zn-2(L)(2)F-4(H2O)(2)] (3a), [Cu2Zn2(L)(2)(H2O)(4)] (4) and K-4[Cu2Zn2(L)(2)F-4(H2O)(2)] (4a) have been synthesized and characterized by analytical, molar conductance, and magnetic data and electronic, EPR, IR and H-1 NMR spectroscopic studies. Monometallic complexes have been shown to contain the coordinated dihydrazone in syn-cis-configuration while the heterobimetallic complexes contain the coordinated dihydrazone in the anti-cis-configuration.