Structural Diversity in Organotin Compounds Derived from Bulky Monoaryl Phosphates: Dimeric, Tetrameric, and Polymeric Tin Phosphate Complexes

Monoaryl phosphates with a bulky aryl substituent have been used to synthesize new organotin clusters and polymers. The equimolar reaction between 2,6‐diisopropylphenylphosphate (dipp‐H 2 ) and Me 2 SnCl 2 in ethanol at 25 °C leads to the formation of [Me 2 Sn(μ 3 ‐dipp)] n ( 1 ), while the reaction of 2,6‐dimethylphenylphosphate (dmpp‐H 2 ) with Me 2 SnCl 2 in either a 1:1 or 2:1 molar ratio proceeds to produce exclusively [Me 2 Sn(μ‐dmpp‐H) 2 ] n · n H 2 O ( 2 ). Compounds 1 and 2 are 1D polymers with different architectures. In compound 1 , the tin atom is five‐coordinate (trigonal bipyramidal). Each dipp ligand bridges three different tin atoms to form an infinite ladder‐chain structure. In 2 , each six‐coordinate (octahedral) tin atom is surrounded by four phosphate oxygen atoms originating from four different bridging dmpp‐H ligands, thus forming a spirocyclic coordination polymeric chain. The use of n Bu 2 SnO as the diorganotin source in its reaction with dipp‐H 2 leads to the isolation of dimeric [ n Bu 2 Sn(μ‐dipp‐H)(dipp‐H)] 2 ( 4 ), which contains a central Sn 2 O 4 P 2 unit. There are two chemically different half molecules of 4 in the asymmetric part of the unit cell and hence it actually exists as a 1:1 mixture of [ n Bu 2 Sn(μ‐dipp‐H)(dipp‐H)] 2 and [ n Bu 2 Sn(μ‐dipp)(dipp‐H 2 )] 2 in the solid state. The reaction of the monoorgano tin precursor n BuSn(O)(OH) · x H 2 O with dipp‐H 2 takes place in acetone at room temperature to yield the tetrameric cluster 5 , which has different structures in the solution and in the solid state. 31 P NMR spectroscopy clearly suggests that 5 has the formula [ n Bu 4 Sn 4 (μ‐O) 2 (μ‐dipp‐H) 8 ] in solution. The single‐crystal X‐ray diffraction studies in the solid state, however, reveal that compound 5 exists as [ n Bu 4 Sn 4 (μ‐OH) 2 (μ‐dipp‐H) 6 (μ‐dipp) 2 ]. The use of compounds 1 – 4 as possible precursors for the preparation of ceramic tin phosphate materials has been investigated. The thermolysis of 1 at 500 °C leads to the formation of quantitative amounts of Sn 2 P 2 O 7 , while the thermolysis of 2 , 3 , and 4 under similar conditions results in the formation of SnP 2 O 7 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)