Studies on organo-phosphorus, -arsenic, and -antimony polytungstates and polymolybdates: V. Syntheses and structures of benzylarsonic polymolybdates

In order to investigate the influence of organic groups on the structural types of organoarsenic polymolybdates, benzylarsonic acid has been selected to react with sodium molybdate. Three new complexes have been synthesized and characterized: [C(NH₂)₃]₄ [(C₆H₅CH₂As)₂Mo₆O₂₄] (1), Cs₄[(C₆H₅CH₂AS)₂Mo₆O₂₄]·5H₂O (2) and [(n-C₄H₉)₄N]₃Na[(C₆H₅CH₂As)₂Mo₆O₂₄] · 6H_aO(3). Molecular structure of compound 1 has been determined by means of single-crystal X-ray diffraction studies. It is monoclinic, space group P2₁/n with cell dimensions of a = 12. 342(2), b = 18.621(2), c = 10.042(2)Å, β = 105.80(1)°, V = 2220.5 ų, z = 2, μ = 15.854 cm⁻¹, R = 0.023. It is demonstrated that the structural types of benzylarsonic polymolybdates are the same as those for alkylarsonic polymolybdates but different from those for arylarsonic polymolybdates. Their elemental analyses, IR and UV spectra and electrochemical behaviors in aqueous solution have been reported. It is suggested that the arsenic—carbon bond has great influence on the structural types of organoarsenic polymolybdates.