Polynuclear chlorine containing organooxotin clusters

Abstract

Reaction of n-butyltin dihydroxy chloride, n-BuSn(OH)2Cl, with the phosphinic acids R2P(O)OH (R = cyc, t-Bu, Ph, Mes) yields the novel chlorooxotin clusters, [{n-BuSn(OH)O2P(C6H11)2} 3O][{n-BuSnCl2O2P(C6H 11)2}2OH] (1), [(n-BuSn(O)O2P(t-Bu)2)(n-BuSn(OH)2O 2P(t-Bu)2)]2[H][Cl][n-BuSnCl(OH)(O 2P(t-Bu)2)]2 (2), [{n-BuSnCl2(O2PPh2)}{n-BuSn(OH)(O 2PPh2)2}]2·2CH 2Cl2 (3), and [(n-BuSn(OH)O2PMes2)3O]Cl (4), respectively, that contain tin nuclearities varying from 2 to 4. All have hydroxyl groups bridging hexacoordinate tin centers and in 1 and 2 these hydroxyl bridges hydrogen bonds to neighboring chlorine atoms. The new compounds 1 and 2 are each composed of two cluster units. In 1 an O-capped cationic cluster hydrogen bonds to a new form of a dinuclear tin anion. Formal replacement of the two phosphinate units attached to each of the central tin atoms of the tetranuclear tin cluster 3 with chlorine atoms generates the new dinuclear tin anion structure of 1. In 2, two distinct compounds cocrystallize, a protonated tetranuclear tin crown cluster which is hydrogen bonded to a chloride ion and a neutral dinuclear tin butterfly unit similarly hydrogen bonded to the chloride. Formulation 4 is representative of an O-capped cluster. 1H, 119Sn, and 31P NMR data are consistent with retention of the solid-state structures in solution. Possible routes for the formation of these new oxotin clusters are presented. 1 crystallizes in the triclinic space group P1 with a = 14.870 (5) Å, b = 15.328 (4) Å, c = 26.117 (8) Å, α = 72.88 (2)°, β = 70.39 (3)°, γ = 70.63 (3)°, and Z = 2. 2 crystallizes in the triclinic space group P1 with a = 13.040 (3) Å, b = 14.334 (5) Å, c = 16.536 (3) Å, α = 71.62 (2)°, β = 71.19 (2)°, γ = 77.33 (2)°, and Z = 1. 3 crystallizes in the orthorhombic space group Pbca with a = 23.544 (6) Å, b = 16.608 (4) Å, c = 25.926 (5) Å, and Z = 4. The final conventional unweighted residuals are 0.060 (1), 0.056 (2), and 0.046 (3). © 1992 American Chemical Society.