Synthesis, Magnetic, and Spectral Studies of Some Mono‐ and Binuclear Dioxomolybdenum(VI) Complexes with Chelating Hydrazones Derived from Acid Hydrazides and Furfural or Thiophene‐2‐aldehyde

This paper deals with the synthesis, magnetic and spectral studies of some mono‐ and binuclear dioxomolybdenum(VI) complexes with chelating hydrazones derived from salicylic acid/benzoic acid/isonicotinic acid hydrazide with thiophene‐2‐aldehyde or furfural. The acid hydrazones synthesized are N‐(furfuralidene)‐N′‐salicyloylhydrazine [FSAH, (I)], N‐(2‐thiophenidene)‐N′‐salicyloylhydrazine [TSAH, (II)], N‐(furfuralidene)‐N′‐isonicotinoylydrazine [FINH, (III)], N‐(2‐thiophenidene)‐N′‐isonicotinoylhydrazine [TINH, (IV)], N‐(furfuralidene)‐N′‐benzoylhydrazine [FBZH, (V)] and N‐(2‐thiophenidene)‐N′‐benzoylhydrazine [TBZH, (VI)]. The metal complexes (1)–(6) were prepared by mixing methanolic solutions of FSAH, TSAH, FINH, TINH, FBZH or TBZH with methanolic solution of [(MoO2(acac)2], and refluxing for 2–4 hours. The resulting compounds have been characterized on the basis of elemental analyses, molar conductances, magnetic measurements, electronic and infrared spectral studies, and were found to have the general formulas [MoO2(L1)(OH)], where L1H = TSAH, TINH or TBZH and [MoO2(L2)(OH)]2, where L2H = FSAH, FINH, or FBZH. A monomeric octahedral structure for compounds [MoO2(L1)(OH)], L1H = TSAH (2), TINH (4) or TBZH (6), and dimeric hydroxo bridges octahedral structures for compounds [MoO2(L2)(OH)]2, L2H = FSAH (1), FINH (3) or FBZH (5) have been tentatively proposed.