Dimeric structures of di-n-butyltin(IV) ortho-substituted dibenzoates
摘要:
Reaction of (n-Bu)2SnO with ortho-substituted benzoic acids yielded the new tin(IV) derivatives (n-Bu)2Sn(O2CC6H4-o-OH)2 (1) and (n-Bu)2Sn(O2CC6H4-o-Cl)2 (2), whose X-ray analyses showed hydrogen bonding in 1 and long Sn-O bridges in 2, leading to dimeric formulations. Solid-state infrared and Sn-119m Mossbauer spectral data indicate carboxylate stretching frequencies and coordination at tin consistent with the X-ray structures. Comparison of related dicarboxylate tin compositions with similar structures reveals a correlation showing an increase in the C-Sn-C angle as the intermolecular Sn-O bond length decreases. The hydroxyl derivative 1 provides the first example of a hydrogen-bridged dimer formation. The geometry at tin is discussed in terms of a bicapped tetrahedron with four normal covalent bonds (two Sn-O and two Sn-C bond distances) and two longer Sn-O distances. The former define the tetrahedra and the latter the capped faces. The hydroxy derivative 1 crystallizes in the monoclinic space group P2(1)/c with a = 9.345 (3) angstrom, b = 24.086 (5) angstrom, c = 10.839 (3) angstrom, beta = 107.77 (2)-degrees, and Z = 4. The chloro derivative 2 crystallizes in the monoclinic space group P2,/c with a = 12.369 (2) angstrom, b = 8.830 (2) angstrom, c = 22.114 (5) angstrom, beta = 102.18 (2); and Z = 4. The final conventional unweighted residuals are 0.038 (1) and 0.028 (2).