Convenient syntheses and structural characterizations of mono-substituted alkylimido hexamolybdates: [Mo₆O₁₈(NR)]²⁻(R = Me, Et, n-Pr, i-Pr, n-Bu, t-Bu, Cy, Hex, Ode)

Abstract

Monofunctionalized alkylimido derivatives of hexamolybdate, (Bu(4)N)(2)[Mo(6)O(18)( identical withN-R)] (R = methyl, Me; ethyl, Et; n-propyl, n-Pr; i-propyl, i-Pr; n-butyl, n-Bu; t-butyl, t-Bu; cyclohexyl, Cy; n-hexyl, Hex; and n-octadecyl, Ode), have been prepared in high purity and good yield by the reaction of [Bu(4)N](4)[alpha-Mo(8)O(26)] with appropriate aliphatic amine hydrochlorides in anhydrous acetonitrile, using N,N'-dicyclohexylcarbodiimide (DCC) as the dehydrating agent. Eight compounds have been determined by single crystal X-ray diffraction analysis and all compounds have been studied with (1)H-NMR, IR, UV-vis, ESI mass spectrometry and cyclic voltammetry. A structural and (1)H-NMR study show beta hydrogen atoms of those alkylimido derivatives of hexamolybdate have strong Brønsted acidity compared to the hydrogen atoms in other positions.