Synthesis of osmium(VI) neopentyl, neopentylidene, and neopentylidyne complexes
作者:Anne M. LaPointe、Richard R. Schrock
DOI:10.1021/om00033a001
日期:1993.9
[PPh4]2[OsO2Cl4] reacts with excess dineopentylzinc in dichloromethane at room temperature to yield purple-brown, water- and air-stable OsO2(CH2-t-Bu)2. OsO2(CH2-t-Bu)2 reacts with 2 equiv of Ta(CH2-t-Bu)(CH2-t-Bu)3 in pentane at -40-degrees-C to yield insoluble [Ta(O)(CH2-t-Bu)3]x and what is proposed to be pseudotetrahedral, thermally unstable Os(CH-t-Bu)2(CH2-t-Bu)2. Os(CH-t-Bu)2(CH2-t-Bu)2 reacts with pyridinium triflate in the presence of excess pyridine to form Os-(C-t-Bu)(CH2-t-BU)2(py)2(O3SCF3), which when treated with LiN(SiMe3)2, NaC5H5, Na[CpCo(P(O)(OEt)2)3], or NaHB(pz)3 in THF yields neopentylidyne complexes of the type Os(C-t-Bu)(CH2-t-Bu)2(L) (L = N(SiMe3)2, eta5-C5H5, CpCo[P(O)(OEt)2]3, HB(PZ)3).
Imido/Oxo Exchange between Osmium and Tantalum as a Route to Os(NAr)2R2 and OsO(NAr)R2 Complexes (NAr = N-2,6-i-Pr2C6H3; R = CH2CMe3, CH2CMe2Ph, CH2SiMe3) and Attempts To Induce .alpha.-Hydrogen Abstraction To Give Alkylidene Complexes
作者:Anne M. LaPointe、Richard R. Schrock、W. M. Davis
DOI:10.1021/om00006a016
日期:1995.6
OsO(2)R(2) (R = CH2-t-Bu, CH(2)CMe(2)Ph) or [OsO2(CH(2)SiMe(3))(2)](n) reacts with 1 or 2 equiv of Ta(NAr)(O-t-Bu)(3) (NAr = N-2,6-i-Pr2C6H3) to form complexes of the type OsO(NAr)R(2) or Os(NAr)(2)R(2). OsO(NAr)(CH2-t-Bu)(2) reacts with 2 equiv of HCl or Me(3)SiI in CH2Cl2 or DME to form Os(NAr)(CH2-t-Bu)(2)Cl-2 or Os(NAr)(CH2-t-Bu)(2)I-2, respectively, or with SiMe(3)X in CH2Cl2 to form green, crystalline Os(NAr)(CH2-t-Bu)(2)(OSiMe(3))(X) (X = Cl, OTf), An X-ray structure of Os(NAr)(CH2-t-Bu)(2)(OSiMe(3))(OTf) showed it to be an approximate square pyramid with a neopentyl group in the apical position. The reaction of OsO(NAr)(CH2-t-Bu)(2) with 2 equiv of trimethylaluminum in pentane yields red trans-Os(NAr)(CH2-t-Bu)(2)(CH3)(2). None of the Os(VI) dineopentyl complexes shows any evidence for controlled alpha-hydrogen abstraction reactions.