Chemistry of oxometal ions-IX. Studies on molybdenyl phosphates

Abstract: Reactions of the complex ion [Mo2O4(C2O4)2(H2O)2]2− (I) have been investigated. On acidification with perchloric acid and hydrochloric acid, complex (I) gave molybdenum(V) aqua-dimer ion [Mo2O4(H2O)6]2+, which was converted into the monomeric species [MoOCl5]2− in concentrated hydrochloric acid. The initial reaction of complex (I) with mercaptoacetic acid, giving a complex of stoichiometry 1 ligand: 1 Mo, was followed by a slower reaction which probably gave higher complexes. In the reactions with o-aminophenol and 2,2′-bipyridyl, complexes of stoichiometry 1 ligand: 1 Mo and 1 ligand: 2 Mo, respectively, were formed in solutions. The following complexes have been isolated: Mo2O4(dtc)2, Mo2O3(dtc)4 (dtc=diethyldithiocarbamate), MoOCl3. phen (phen=1,10-phenanthroline), and Mo2O3Cl4(bpy)2 (bpy=2,2′-bipyridyl). The infrared and electronic spectra of the complexes and their probable structures are given. The relative ease of replacement of ligands from complex (I) has been discussed.

Abstract: Starting from molybdenum trioxide 2,2′-bipyridinium oxopentachloromolybdate(V) BipyH2[MoOCl5] has been isolated in pure state as greenish yellow crystalline solid. From this salt the nonelectrolytic paramagnetic complex MoOCl3·bipy has been isolated in three different isomeric (colored reddish pink, pale khaki and green) forms by dehydrohalogenation in suitable solvent and solid state reaction. The diamagnetic complex Mo2O4Cl2(bipy)2 has been isolated by hydrolysis of the parent salt. All these products and the parent salt have been shown to be interconvertible. The constitution of expected cis-trans isomers of MoOCl3·bipy has also been discussed. All these compounds have been studied by various physicochemical methods and it has been shown that the oxometal entity MoO3+ remains intact under various chemical environments.

Abstract: 1,10 Phenanthrolinium oxopentachloro molybdate(V), PhenH 2 [MoOCl 5 ] has been isolated as yellowish-green solid and from this salt the non-electrolytic paramagnetic complexes MoOCl 3 ·phen have been prepared in three different isometric (colored reddish-pink, pale brown and green) forms by dehydrohalogenation in suitable solvent and solid state reaction. Hydrolysis of the parent salt yielded the diamagnetic complex, Mo 2 O 4 Cl 2 (phen) 2 as brownish red solid. All these products and the parent salt have been shown to be interconvertible and the probable constitution of expected cis-trans isomers of MoOCl 3 ·phen has also been discussed. All these compounds have been studied by various physicochemical methods and it has been shown that the oxometal entity MoO 3+ remains intact under various chemical environments.

Abstract: 1, 10-phenanthrolinium oxopentabromolybdate(v) has been isolated in pure state as greenish yellow powdery solid. During the study of its reactions, (MoOBr3.phen) was isolated as a product of dehydrohalogenation, and (Mo2O3Br4 phen2) and (Mo2O4Br2phen2) were isolated by hydrolysing the parent salt. The compound (MoOBr3.phen) has been isolated in two coloured forms (red and deep chocolate) expected to be the two stereoisomeric varieties cis- and trans-, as evidenced by their reactions. All the compounds have been studied using various physicochemical methods. Their interconversions clearly reveal the extraordinary stability of the various oxomolybdenum species MoO3, Mo2O34+ and Mo2O42+ under different environments.