Synthesis and characterization of octamolybdates containing co-ordinatively bound salicylideneiminato and methioninato (MetO) ligands. Crystal structures of [NH3Pr]2[Mo8O22(OH)4(OC6H4CHNPr-2)2]·6MeOH and [Hmorph]4[Mo8O24(OH)2(MetO)2]·4H2O (morph = morpholine)

Abstract

The compound [MoO₂(sal)₂](Hsal = salicylaldehyde) reacts with n-propylamine in methanol to give [NH₃Pr]₂[Mo₈O₂₂(OH)₄(OC₆H₄CHNPr-2)₂]·6MeOH (1). The same complex was obtained by the reaction of ammonium paramolybdate with N-propylsalicylideneimine. The structure determined by X-ray analysis showed that the octamolybdate anion consists of eight condensed octahedra with 16 terminal positions, two of which are occupied by the salicylideneiminato ligands. The reaction of MoO₂Cl₂ with methionine yields the neutral complex [Mo₈O₂₀(OH)₄(MetO)₄]·solvent (2)(solvent = H₂O or MeOH, MetO = methioninate). If the methanolic solution of (2) is neutralized with morpholine (morph) the anionic complex [Hmorph]₄[Mo₈O₂₄(OH)₂(MetO)₂]·4H₂O (3) is obtained. It has been shown by X-ray analysis that the structure of (3) is analogous to that of (1) with two MetO ligands linked to two terminal sites of the Mo₈O₂₆ core.