The crystal and molecular structures of R₂Sn(O₂CR¹)Cl: R = Me, tBu and Ph; ⁻O₂CR¹ = o-(2-hydroxy-5-methylphenylazo)benzoate

Abstract

The crystal and molecular structures of three R₂Sn(O₂CR¹)Cl compounds [R = Me, tBu and Ph; ⁻O₂CR¹ = o-(2-hydroxy-5-methylphenylazo)benzoate] have been determined at room temperature. Brown crystals of Me₂Sn(O₂CR¹)Cl (1), C₁₆H₁₇ClN₂O₃Sn, are triclinic, space group P[unk] with unit cell dimensions a = 10.649(4) Å, b = 12.292(3) Å, c = 7.236(2) Å, α = 96.68(3)°, β = 104.03(3)°, γ = 109.12(3)°, Z = 2 and D_x = 1.662 Mg m⁻³. Red crystals of tBu₂Sn(O₂CR¹)Cl (2), C₂₂H₂₉ClN₂O₃Sn, are monoclinic space group P2₁/n with unit cell dimensions a = 8.323(5) Å, b = 24.990(5) Å, c = 12.403(5) Å, β = 107.94(3)°, Z = 4 and D_x = 1.417 Mg m⁻³. Red crystals of Ph₂Sn(O₂CR¹)Cl (3), C₂₆H₂₁ClN₂O₃Sn, are also monoclinic with space group P2₁/c and unit cell dimensions a = 14.416(3) Å, b = 16.373(6) Å, c = 10.489(4) Å, β = 97.10(3)°, Z = 4 and D_x = 1.524 Mg m⁻³ The structures were solved by Patterson (1 and 2) or direct methods (3) and each refined by a full-matrix least-squares procedure to final R = 0.039 using 2933 reflections for 1, R = 0.039 for 2935 reflections for 2, and R = 0.037 using 2863 reflections for 3. The structure of 1 is dimeric with the two tin atoms being bridged by two ⁻O₂CR¹ anions each of which coordinates a tin atom via one of the carboxylate oxygen atom and the second tin atom via the phenoxide oxygen atom; this result indicates that the ⁻O₂CR¹ anion exists as a Zwitterion. The tin atom geometry is trigonal bipyramidal. trans-O₂SnC₂Cl. By contrast to the dimeric structure for 1, the structures of 2 and 3 are monomeric with the tin atoms in cis-O₂SnC₂Cl trigonal bipyramidal geometries. The ⁻O₂CR¹ anion coordinates the tin atom in each of 2 and 3 via the carboxylate oxygen atoms only.