Hybrid Organic−Inorganic Assemblies Based on Molybdates and Dimethyltin Linkers

Reaction of (CH3)2SnCl2 with Na2MoO4 in an aqueous medium results in three different compounds depending on
the pH:  [{(CH3)2Sn}(MoO4)] (1), [{(CH3)2Sn}4O2(MoO4)2] (2), and [{(CH3)2Sn}{Mo2O7(H2O)2}]·H2O (3). All three
species have been characterized in the solid state by means of elemental analysis, infrared spectroscopy,
thermogravimetry, and single-crystal X-ray diffraction. Compounds 1−3 all show hybrid organic−inorganic extended
lattices based on molybdate anions linked by (CH3)2Sn2+ moieties, and the coordination numbers of the Sn(IV)
centers range from 5 to 7. Compound 1 crystallizes in the orthorhombic space group Pnma with cell parameters
a = 13.2035(4) Å, b = 7.2634(2) Å, c = 7.1458(2) Å, and Z = 4. 1 exhibits a complex, 3-dimensional network
structure constructed of corner-shared, tetrahedral orthomolybdate oxoanions and distorted octahedral trans-(CH3)2SnO4 groups. Compound 2 crystallizes in the monoclinic space group P21/n with cell parameters a = 8.2330(1) Å,
b = 11.4033(2) Å, c = 12.1529(2) Å, β = 91.566(1)°, and Z = 2. Its 2-dimensional layered structure contains
dimeric tetramethyldistannoxane [{(CH3)2Sn}4O2]2+ subunits built up of edge-sharing cis-(CH3)2SnO4 distorted trigonal
bipyramids and connected in the (1,0,1̄) plane by tetrahedral orthomolybdate oxoanions, the layers packing along
the crystallographic a axis with the methyl groups pointing to the interlamellar space. Compound 3 crystallizes in
the orthorhombic space group Pbcm with cell parameters a = 6.5594(4) Å, b = 14.2465(11) Å, c = 11.3892(8)
Å, and Z = 4. It shows dimeric [Mo2O8(H2O)2] units sharing corners to form zigzagging polymeric {[Mo2O7(H2O)2]2-}∞
polyanions along the [001] direction; these chains are further linked by trans-(CH3)2SnO5 distorted pentagonal
bipyramids to give layers parallel to the (010) plane, the interlamellar space being occupied by hydrogen-bonded
hydration water molecules.