Dipole moments and conformational analysis of tris(2-pyridyl)phosphine and tris(2-pyridyl)phosphine chalcogenides. Experimental and theoretical study

Conformational analysis of tris(2-pyridyl)phosphine and tris(2-pyridyl)phosphine chalcogenides was carried out by the method of dipole moments and density functional theory calculations. The conformations of the examined compounds fit into the overall conformational picture for the PIII and PIV compounds: namely, these phosphines have non-eclipsed gauche- and trans-forms with propeller arrangement of the pyridyl radicals about the P = Y bond (Y = lone pair, O, S, Se).