Hydrogen bonding in hydroxymethylphosphine chalcogenides

Hydrogen bonding in the phosphine chalcogenide series Ph2P(X)CH2OH (X=O, 1; S, 2; Se, 3) has been investigated by single crystal X-ray crystallography. While the phosphine oxide exhibits a dimer motif, the sulfide and selenide form infinite chains; in all cases hydrogen bonding is from the OH group to the phosphine chalcogenide heteroatom. The trend in the hydrogen bond angle for OH⋯X–P, which is 117, 87 and 84° for the oxide, sulfide and selenide, respectively, is explained with respect to the geometry of electron density on the phosphine chalcogenide heteroatom.