Polymorphism of 2,5-[(diphenylphosphanyl)methyl]-1,1,2,4,4,5-hexaphenyl-1,4-diphospha-2,5-diboracyclohexane

Abstract

2,5-[(Diphenylphosphanyl)methyl]-1,1,2,4,4,5-hexaphenyl-1,4-diphospha-2,5-diboracyclohexane shows polymorphism as two tetrahydrofuran (THF) disolvates [C64H58B2P4·2C4H8O, (Ia) and (Ib)] and pseudo-polymorphism as its toluene monosolvate [C64H58B2P4·C7H8, (Ic)]. In each of polymorphs (Ia) and (Ib), the diphosphadiboracyclohexane molecule is located on a centre of inversion. The THF molecule of (Ib) is disordered over two sites, with a site-occupation factor of 0.612 (8) for the major-occupied site. Both structures crystallize in the same space group (P21/n), but they display a different crystal packing. For pseudo-polymorph (Ic), although the space group is P21/c, which is just a different setting of the P21/n space group of (Ia) and (Ib), the crystal packing is completely different. Although the crystal packing in these three structures is significantly different, their molecular conformations are surprisingly the same.