Dimeric structures of Di-n-butyltin(IV) ortho-substituted dibenzoates

Article abstract of DOI:10.1021/om00042a039

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 (U-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 ^119mSn M?ssbauer 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 P2₁/c with a = 9.345 (3) ?, b = 24.086 (5) ?, c = 10.839 (3) ?, β = 107.77 (2)°, and Z = 4. The chloro derivative 2 crystallizes in the monoclinic space group P2₁/c with a = 12.369 (2) ?, b = 8.830 (2) ?, c = 22.114 (5) ?, β = 102.18 (2); and Z = 4. The final conventional unweighted residuals are 0.038 (1) and 0.028 (2).