THE CRYSTAL AND MOLECULAR-STRUCTURES OF R2SN(O2CR1)CL - R = ME, TBU AND PH, (-O2CR1) = O-(2-HYDROXY-5-METHYLPHENYLAZO)BENZOATE

The crystal and molecular structures of three R2Sn(O2CR1)CI compounds [R=Me, tBu and Ph; ?(-O2CR1) = o-(2-hydroxy-5-methylphenylazo)benzoate ] have been determined at room temperature. Brown crystals of Me2Sn(O2 CR1)Cl (1), C16H17ClN2O3Sn,are triclinic, space group P (1) over bar w ith unit cell dimensions a = 10.649(4) Angstrom, b = 12.292(3) Angstro m, c = 7.236(2) Angstrom, alpha = 96.68(3)degrees, beta = 104.03(3)deg rees, gamma = 109.12(3)degrees, Z = 2 and D-x, = 1.662 Mg m(-3). Red c rystals of tBu(2)Sn(O2CR1)Cl (2), C22H29ClN2O3Sn, are monoclinic space group P2(1)/n with unit cell dimensions a = 8.323(5) Angstrom, b = 24 .990(5) Angstrom, c = 12.403(5) Angstrom, beta = 107.94(3)degrees, Z = 4 and D-x = 1.417 Mg m(-3). Red crystals of Ph2Sn(O2CR1)Cl (3), C26H2 1ClN2O3Sn, are also monoclinic with space group P2(1)/c and unit cell dimensions a = 14.416(3) Angstrom, b = 16.373(6) Angstrom, c = 10.489( 4) Angstrom, beta = 97.10(3)degrees, 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 oxyge n atom and the second tin atom via the phenoxide oxygen atom; this res ult 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 w ith the tin atoms in cis-O-2?SnC2?Cl trigonal bipyramidal geometries. The (-O2CR1) anion coordinates the tin atom in each of 2 and 3 via the carboxylate oxygen atoms only.