Crystal structures and hydrogen-bonding analysis of a series of solvated ammonium salts of molybdenum(II) chloride clusters

Abstract

Charge-assisted hydrogen bonding plays a significant role in the crystal structures of solvates of ionic com­pounds, especially when the cation or cations are primary ammonium salts. We report the crystal structures of four ammonium salts of molybdenum halide cluster solvates where we observe significant hydrogen bonding between the solvent molecules and cations. The crystal structures of bis­(anilinium) octa-μ₃-chlorido-hexachlorido-octahedro-hexamolybdate N,N-dimethylformamide tetrasolvate, (C₆H₈N)₂[Mo₆Cl₈Cl₆]·4C₃H₇NO, (I), p-phenylenediammonium octa-μ₃-chlorido-hexachlorido-octahedro-hexamolybdate N,N-dimethylformamide hexasolvate, (C₆H₁₀N₂)[Mo₆Cl₈Cl₆]·6C₃H₇NO, (II), N,N′-(1,4-phenylene)bis­(propan-2-iminium) octa-μ₃-chlorido-hexachlorido-octahedro-hexamolybdate acetone trisolvate, (C₁₂H₁₈N₂)[Mo₆Cl₈Cl₆]·3C₃H₆O, (III), and 1,1′-dimethyl-4,4′-bipyridinium octa-μ₃-chlorido-hexachlorido-octahedro-hexamolybdate N,N-dimethylformamide tetrasolvate, (C12H14N2)[Mo₆Cl₈Cl₆]·4C₃H₇NO, (IV), are reported and described. In (I), the anilinium cations and N,N-dimethylformamide (DMF) solvent molecules form a cyclic R₄²(8) hydrogen-bonded motif centered on a crystallographic inversion center with an additional DMF molecule forming a D(2) interaction. The p-phenylenediammonium cation in (II) forms three D(2) inter­actions between the three N—H bonds and three independent N,N-dimethylformamide molecules. The dication in (III) is a protonated Schiff base solvated by acetone molecules. Compound (IV) contains a methyl viologen dication with N,N-dimethylformamide molecules forming close contacts with both aromatic and methyl H atoms.