The hybrid organic-inorganic 2-d material (CsNa2[{Sn(CH3)2}3(H2O)4-(β-XW9O33)]•7H2O)∞ (X = AsIII, SbIII) and its solution properties

We report on the hybrid organic-inorganic 2-D materials (CsNa2[{Sn(CH3)(2)}(3)(H2O)(4)(beta-AsW9O33)](.)7H(2)O)(infinity) (1a) and the isomorphous (CsNa2[{Sn(CH3)(2)}(3)(H2O)(4)(beta-SbW9O33)](.) 7H(2)O)(infinity) (2a) which crystallize in the orthorhombic system, space group Pna2(1), with identical unit cell parameters a = 26.118(2) Angstrom, b = 16.064(1) Angstrom, c = 13.776(1) Angstrom, and Z = 1. Compounds 1a and 2a have been synthesized in good yield by crystallization from a reaction mixture of dimethyltin dichloride and Na-9[alpha-XW9O33] (X = As-III, Sb-III) in aqueous, acidic medium. We have shown by multinuclear NMR spectroscopy (W-183, Sn-119, C-13, H-1) that 1a and 2a decompose in solution leading to the monomeric species [{Sn(CH3)(2)(H2O)(2)}(3)(beta- XW9O33)](3-) [X = As-III (1), Sb-III (2)]. Polyanions 1 and 2 consist of a (beta-XW9O33) fragment stabilized by three dimethyltin units. The dimethyltin groups are grafted onto the polyanion by two Sn-O(W) bonds on the side of the heteroatom lone pair. Compounds 1 and 2 are rare examples of discrete polyoxoanions which polymerize upon crystallization leading to a 2-D solid-state structure with inorganic and organic surface regions. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).