Study of Conversion of Polymeric Organophosphorus Ylide Complexes of Mercury(ii) Halides to Phenazine Complexes: X-RAY Crystal Structures and Spectral Characterizations

The reaction of PPh₃ with BrCH₂C(O)PhNO₂ leads to a new phosphonium salt [Ph₃P-CH₂C(O)PhNO₂]Br (<b>1</b>). Reaction of the salt <b>1</b> with an appropriate base gave the free ligand, Ph₃P = C(H)C(O)PhNO₂ (<b>2</b>). The reactions of ligand <b>2</b> with mercury(II) halides form the C-coordinated polymeric complexes [(<b>2</b>)HgX₂]_n {X = Cl (<b>3</b>), Br (<b>4</b>), I (<b>5</b>)}. Reactions of benzo[<i>a</i>]quinoxalino[2,3-<i>c</i>]phenazine ligand (L) with complexes <b>3</b>, <b>4</b> and <b>5</b> cause the removal of ylidic ligand and lead to the formation of a new set of mononuclear mercury halides complexes {[(L)HgCl₂] (<b>6</b>), [(L)HgBr₂] (<b>7</b>) and [(L)HgI₂] (<b>8</b>)} containing (L<b>)</b> as a bidentate ligand. The structures of <b>4</b> and <b>6</b> were confirmed by single-crystal X-ray analysis. The structure of the products were identified by IR, ¹H and ³¹P NMR spectral data and elemental analysis.