화학공학소재연구정보센터
Inorganic Chemistry, Vol.37, No.15, 3848-3852, 1998
Structural determination and acidolysis reactions of ortho-metalated rhenium tetrahydride compounds prepared from reactions of ReH7(PPh3)(2) with benzylic imines
Reactions between ReH7(PPh3)(2) and a series of benzylic imines, PhCHNR (R = Me, Ph, or Bn), produce the compounds ReH4[eta(2)-(1,2-C6H4)CHNR](PPh3)(2). One such compound, ReH4[eta(2)-(1,2-C6H4)CHNPh] (PPh3)(2), was characterized by X-ray diffraction analysis. The compound ReH4[eta(2)-(1,2-C6H4)CHNPh](PPh3)(2) crystallizes in the P-(1 over bar) space group with the following unit cell dimensions : a = 12.422(3) Angstrom, b = 12.696(3) Angstrom, c = 13.604(5) Angstrom, alpha = 93.26(2)degrees, beta = 90.66(2)degrees, gamma = 107.03(2)degrees, V = 2047.2 Angstrom(3), and Z = 2. The structure was refined to R(F-o) = 0.029 (R-w(F-o) = 0.034) for 5352 data with I > 3.0 sigma(I). The structure determination indicates that orthometalation of the imine reactant occurs during the reaction of ReH7(PPh3)(2) With PhCHNPh, The observation of four v(Re-H) absorptions in the infrared spectrum of each ReH4[eta(2)-(1,2-C6H4)CHNR](PPh3)(2) compound indicates that the rhenium-bound hydrogen atoms, in these compounds, are better regarded as classical hydride ligands rather than as elongated dihydrogen ligands. Acidolysis reactions of the compounds ReH4[eta(2)-(1,2-C6H4)CHNR]-(PPh3)(2), with HBF4. Et2O in acetonitrile, result in loss of the ortho-metalated imine ligands from the rhenium coordination spheres and in reduction of the imine functional groups to secondary ammonium cations. One hydride ligand is transferred to the imine carbon atom, during the course of each acidolysis reaction.