Synthesis, crystal structures and spectra of Hg(II)-1,2-bis(diphenylphosphino)ethane monoxide complexes: Monomer and polymer formation

The reaction of mercury(II) halides with 1,2-bis(diphenylphosphino)ethane monoxide (dppeO) in 1:1 molar ratio yielded P,O-coordinated polymers having the empirical formula [HgX₂ (dppeO)]_<i>n</i> [X = Cl (<b>1</b>), Br (<b>2</b>), I (<b>3</b>)]. In contrast, the reaction between the same reactants in a 1:2 molar ratio yielded the P, P-coordinated monomeric complexes, HgX₂ (dppeO)₂[X = Cl (<b>4</b>), Br (<b>5</b>), I (<b>6</b>)]. The structures of <b>2</b>, <b>3</b>, <b>4</b> and <b>5</b> have been characterized crystallographically. The results indicate that the geometry around the mercury atom in each of these molecules is tetrahedral with considerable distortion. The </sup>31</sup>P NMR spectra of the 1:1 complexes indicate the dissociation of the Hg–O bond in solution.