Oxidative addition of bis[2-(4,4-dimethyl-2-oxazolinyl)phenyl] diselenide to Pd(PPh3)4 provided two different mononuclear palladium selenolato complexes, Pd(Se∩N)(PPh3)Cl (4) [Se∩N = chelating 2-(4,4-dimethyl-2-oxazolinyl)phenylselenolate] and Pd(Se∩N)(Se∩N*) (PPh3) (5) [Se∩N = chelating, Se∩N* = non-chelating 2-(4,4-dimethyl-2-oxazolinyl)phenylselenolato ligand] in dicholoromethane and toluene respectively. Complex 4 has also been synthesized by the oxidative addition of 2-(4,4-dimethyl-2-oxazolinyl)phenylselenenyl chloride to Pd(PPh 3)4. The bromo and iodo analogs of 4 (9 and 10) were similarly synthesized by the oxidative addition of 2-(4,4-dimethyl-2-oxazolinyl) phenylselenenyl bromide and iodide, respectively to Pd(PPh3) 4. The oxidative addition of 2-(N,N-dimethylaminomethyl) phenylselenenyl bromide and iodide to Pd(PPh3)4 afforded mononuclear palladium selenolate complexes, Pd(Se∩N)(PPh3)X (13 and 14) [Se∩N = chelating 2-(N,N-dimethylaminomethyl)phenylselenolate, X = Br: 13, X = I: 14]. The reactions of bis[2-(4,4-dimethyl-2-oxazolinyl)phenyl] diselenide and bis[2-(N,N-dimethylaminomethyl)phenyl] diselenide with Pd(COD)Cl2 provided dinuclear selenolato-bridged complexes [PdCl(Se∩N)]2 (15) [Se∩N = chelating 2-(4,4-dimethyl-2- oxazolinyl)phenylselenolate] and [PdCl(Se∩N)]2 (19) [Se∩N = chelating 2-(N,N-dimethylaminomethyl)phenylselenolate] respectively. The complexes were characterized by elemental analysis and NMR (1H and 77Se) spectroscopy. Complexes 4 and 5 were also characterized by mass spectrometry. Molecular structures of 4, 5, 9, 14 and 15 have been established by single crystal X-ray diffraction analysis. Complexes 4 and 9 are isomorphous and crystallize in the space group P21/c of the monoclinic system where the selenolato and halo ligands are trans to each other. Complex 5 crystallizes in the space group P21/n of the monoclinic system where one chelating and one non-chelating selenolato ligands are trans to each other. Mononuclear complex 14 and binuclear centrosymmetric complex 15 crystallize in the P1 space group of the triclinic system.
Bibliographical noteFunding Information:
We are thankful to the Department of Science and Technology (DST), India for funding this work. Additional help from the Sophisticated Analytical Instrument Facility (SAIF), Indian Institute of Technology, Bombay, for 300 MHz NMR spectroscopy is gratefully acknowledged. T. C. and K. S. are also grateful to the Council of Scientific and Industrial Research, India for providing fellowship.
- Oxidative addition
- Selenenyl halide