Facile Synthesis of Novel Two- And Three-Dimensional Coordination Polymers Containing Dialkyltin Phosphonate-Based Tri/Tetra-Nuclear Clusters with Appended Sulfonate Groups

The coordination-driven self-assemblies of mixed-ligand dialkyltin derivatives, [(Et(2)Sn)(4) (O(2)P(OH)Me)(2)(O(3)PMe)(2)-OSO(2)Et)(2)center dot 2H(2)O](n) 1, [(Et(2)Sn)(3)(O(3)PMe)(2)(OSO(2)Me)(2)center dot CHCl(3)](n) 2, and [(Me(2)Sn)(3)(O(3)PBu(t))(2)(OSO(2)Me)(2)center dot 2CHCl(3)](n) 3 have been achieved by reacting the tin precursors, [R(2)Sn(OR(1))(OSO(2)R(1))](n) (R = Et, R(1) = Et (1a), Me (2a); R = Me, R(1) = Me (3a)) with an equimolar amount of methylphosphonic/t-butylphosphonic acid under mild conditions (rt, 8 h, CH(2)Cl(2)). These have been characterized by IR and multinuclear ((1)H, (13)C, (31)P, and (119)Sn) NMR spectroscopy as well as single crystal X-ray diffraction. The asymmetric unit of 1 is composed of a tetranuclear, Sn(4)(mu(2)-PO(2))(2)(mu(3)-PO(3))(2) core bearing an appended ethanesulfonate group on each terminal tin (Sn2) atom and two P(OH)center dot center dot center dot O hydrogen bonded water molecules. The ladder-like structural motif thus formed is extended into one-dimensional polymeric chains by virtue of bridging bidentate mode of the sultonate groups. These chains are linked by O-H center dot center dot center dot O(S) hydrogen bonds involving H(2)O molecules and oxygen atoms of the sulfonate groups. The asymmetric units of 2 and 3 are composed of trinuclear tin clusters with a Sn(3)(mu(3)-PO(3))(2) core and two dangling methanesulfonate groups which are covalently bonded to the tin centers. The construction of three-dimensional self-assemblies is effected by variable bonding modes (mu(2), mu(3) in 2; mu(2) in 3) of the methanesulfonate groups. Both the structural motifs possess five- and six-coordinated tin atoms and form rectangular channels which are occupied by CHCl(3) molecules.