Coordination behaviour of diphosphine and diarsine oxides in four organotin(IV) adducts

Abstract

Four new molecular adducts of diphenyl- and triphenyl-tin(IV) nitrates with 1,2-bis(diphenylarsoryl)ethane (dpaoe), bis(diphenylphosphoryl)methane (dppom) and trans-1,2-bis(diphenylphosphoryl)ethylene (tdppoet) have been synthesised and characterized by infrared spectroscopy, and an X-ray diffraction study has been carried out on two of them, {SnPh 3NO 3} 2dpaoe ( 1) and SnPh 2(NO 3) 2dppom ( 2). Both 1 and 2 crystallize in the triclinic space group P 1 , with unit-cell dimensions. 1: a 12.810(8), b 11.938(6), c 10.394(4) Å, α 97.92(4), β 90.00(5), γ 111.13(4)°, Z = 1, R = 0.0454; 2: a 13.845(6), b 13.119(4), c 10.444(6) Å, α 106.50(4), β 101.24(4), γ 91.33(4)°, Z = 2, R = 0.0504. The structure of 1 consists of binuclear monomeric units in which each tin atom is bound in a trigonal bipyramidal configuration to three phenyl rings in the equatorial plane and to the diarsine ligand and the nitrate group in the axial positions. In compound 2 the tin atom exhibits a pentagonal-bipyramidal coordination geometry with five oxygen atoms, two from the chelating dppom ligand and three from the two nitrate groups, around the pentagonal girdle, and the two phenyl groups at the apices of the bipyramid. The vibrational frequencies of the nitrate groups and of the diarsine and diphosphine ligands are discussed in the light of the X-ray results.