Polymer complexes. LVII. Supramolecular assemblies of novel polymer complexes of dioxouranium(VI) with some substituted allyl azo dye compounds

Abstract

A novel method to synthesize some dioxouranium(VI) polymer complexes of the general formula [UO2(Ln)2(OAc)2] (where HLn=azo allyl rhodanine). The structure of the novel mononuclear dioxoutranium(VI) polymer complexes was characterized using elemental analysis, spectral (electronic, infrared, 1H &13C NMR) studies, magnetic susceptibility measurements and thermal analysis. The molar conductivities show that all the polymer complexes are non-electrolytes. The IR showed that the ligand HLn act as bidentate neutral through carbonyl group and imine group nitrogen atom forming thereby a six-membered chelating ring and concomitant formation of an intramolecular hydrogen bond. The υ3 frequency of UO2+2 has been shown to be an excellent molecular probe for studying the coordinating power of the ligands. The values of υ3 of the prepared complexes containing UO2+2 were successfully used to calculate the force constant, FUO (10−8N/Å) and the bond length RUO (Å) of the UO bond. A strategy based upon both theoretical and experimental investigations has been adopted. The theoretical aspects are described in terms of the well-known theory of 5d–4f transitions. Wilson’s, matrix method, Badger’s formula, and Jones and El-Sonbati equations were used to calculate the UO bond distances from the values of the stretching and interaction force constants. The most probable correlation between UO force constant to UO bond distance were satisfactorily discussed in term of Badger’s rule and the equations suggested by Jones and El-Sonbati. The effect of Hammet constant is also discussed.