Synthesis and single crystal structure of a three coordinate complex of mercury(II) with 1-(ethylthio)-2-(diphenylphosphino) ethane (L) prepared by a new simple method

The (P, S) ligand 1-(ethylthio)-2-(diphenylphosphino) ethane (L) is synthesized by reacting Ph2PLi with CH3CH2SCH2CH2Cl. The yield is good (∼85%) and the method of preparation is simpler than the liquid ammonia based one reported earlier. Its complexation with Cu(I), Hg(II) and organometallic species of Ru(II) are explored. All the complexes and the ligand exhibit characteristic proton, carbon-13 and phosphorus-31 NMR spectra. The single crystal structure of the Hg(II) complex has been determined. It is found to be a three coordinate complex. The sum of the bond angles at Hg, viz. P(1)–Hg(1)–Br(1), P(1)–Hg(1)–Br(2) and Br(1)–Hg(1)–Br(2), is ≈360°. Thus the geometry around Hg can best be described as essentially trigonal planar. The Hg(1)–P(1) bond length is 2.415(1) Å and the Hg–Br bond lengths are 2.5152(6) and 2.5952(6) Å. There exists a weak secondary interaction between Hg and the S donor site of the ligand [Hg(1)⋯S(1) bond distance 3.063(1) Å < sum of van der Waal’s radii 3.35 Å].

Graphical abstractThe (P, S) ligand 1-(ethylthio)-2-(diphenylphosphino) ethane (L) is synthesized in good yield by reacting Ph2PLi with CH3CH2SCH2CH2Cl. Its complexation with Cu(I), Hg(II) and organometallic species of Ru(II) are explored. The single crystal structure of Hg(II) complex of L has been determined. It is found to be a three coordinate species. The geometry of Hg can be best described as trigonal planar. The Hg(1)–P(1) bond length is 2.415(1) Å and the Hg–Br bond lengths are 2.5152(6) and 2.5952(6) Å. There exists a weak secondary interaction between Hg and the S donor site of the ligand.Figure optionsDownload full-size imageDownload as PowerPoint slide