Synthesis and characterization of phenoxarsin-10-yl diorganodithiophosphinates. A folded phenoxarsine system in the first dimeric organoarsenic(III) 1,1-dithiolate associated through As ⋯ S secondary bonding
Some phenoxarsin-10-yl diorganodithiophosphinates, O(C6H4)2AsS2PR2(R = Me, Et or Ph), have been prepared by treating 10-chlorophenoxarsine with salts of the corresponding dithio compounds in CH2Cl2. The compounds were characterized by IR, mass spectrometry and 1H, 13C and 31P NMR spectroscopy and the crystal structure of O(C6H4)2AsS2PPh2 has been determined. The compound is monoclinic, space group P2/n, a= 8.925(6), b= 22.028(8), c= 11.341(5)Å, β= 100.70(2)° and Z= 4. It exhibits a dimeric, quasi-tricyclic structure based upon intra- and inter-molecular As ⋯ S secondary bonds (3.402 and 3.381 Å, respectively), which is unique in arsenic–sulfur chemistry. The phenoxarsine unit is non-planar with a dihedral angle of 154.4° between the planes of the two aromatic rings.