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

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)]. 1.5H(2)O 1 and [NMe4](2)[NH4](2)[Mo8O26]. 2H(2)O 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) Angstrom, V = 5557.3(1) Angstrom(3), Z = 4; 2, monoclinic, space group C2/m 1, a = 11.2641(1), b = 16.3815(1), c = 10.0775(1) Angstrom, beta = 110.242(1)degrees, V = 1744.68(3) Angstrom(3), Z = 2. Compound 1 contains layers of disordered dimethylammonium ions alternating with mixed-valent Keggin clusters which are surrounded by tetramethylammonium cations. The structure of 2 is characterised by the presence of layers containing tetramethylammonium cations alternating with layers containing beta-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.