SYNTHESIS, SPECTRAL AND ELECTROCHEMICAL STUDIES OF DIOXOTUNGSTEN(VI) COMPLEXES OF BINUCLEATING SCHIFF-BASES DERIVED FROM METHYLENE(SALICYLALDEBYDE) OR DITHIO-BIS(SALICYLALDEBYDE) AND VARIOUS HYDRAZIDES
Mr. Maurya et al., SYNTHESIS, SPECTRAL AND ELECTROCHEMICAL STUDIES OF DIOXOTUNGSTEN(VI) COMPLEXES OF BINUCLEATING SCHIFF-BASES DERIVED FROM METHYLENE(SALICYLALDEBYDE) OR DITHIO-BIS(SALICYLALDEBYDE) AND VARIOUS HYDRAZIDES, Indian journal of chemistry. Sect. A: Inorganic, physical, theoretical & analytical, 34(12), 1995, pp. 967-970
The syntheses of binuclear dioxotungsten(VI) complexes of the type [(W
O2)(2)L], where L is a flexibly bridged hexadentate tetraanionic schif
f base derived from the condensation of methylene- or dithiobis(salicy
laldehyde) with isonicotinoylhydrazide, benzoylhydrazide, p-nitrobenzo
ylhydrazide and furoylhydrazide are reported. The IR and NMR spectral
data suggest an oligomeric structure for these complexes in which each
tungsten atom achieves a pseudo-octahedral structure via W - O-->W br
idging. Cyclic voltammetric measurements indicate irreversible to quas
ireversible reduction of the dioxotungsten(VI) complexes to oxotungste
n(IV) with a cathodic reduction potential of - 1.0 to - 1.1 V vs SCE a
t the scan rate of 500 mV/s. The bridging methylene (- CH2 -) or dithi
o (- S - S -) group has very little effect on the thermodynamic stabil
ity of the complexes.