Two new inorganic-organic hybrid salts: [NH2Me2]4[NMe4]2- [Mo0.5O4 subset of (Mo12O36)] · 1.5H2O and [NMe4]2[NH4]2[Mo8O26] · 2H2O

Abstract

The present paper reports the formation of two novel organic-inorganic hybrid structures from acidified, aqueous ammonium molybdate solution containing tetramethylammonium ions, [NH2Me2]4[NMe4]2[Mo0.5O4 subset of (Mo12O36)] · 1.5H2O 1 and [NMe4]2[NH4]2[Mo8O26] · 2H2O 2. While 1 is crystallised in the presence of a reducing agent, hydrazine hydrate, 2 is formed in its absence. Crystal data: 1, orthorhombic, space group Pnma, a=22.4037(2), b=19.5153(2) and c=12.7108(2) Å, V=5557.3(1) Å3, Z=4; 2, monoclinic, space group C2/m, a=11.2641(1), b=16.3815(1), c=10.0775(1) Å, β=110.242(1)°, V=1744.68(3) Å3, Z=2. Compound 1 contains layers of disordered dimethylammonium ions alternating with mixed-valent Keggin clusters which are surrounded by tetramethytammonium cations. The structure of 2 is characterised by the presence of layers containing tetramethylammonium cations alternating with layers containing β-Mo8O26 anions; the cavity formed between the anionic clusters is occupied by an unusual eight-membered hydrogen bonded cluster formed between two ammonium ions and two water molecules.