| The synthesis and characterization of several derivatives of lithiated biscyclopentadienyl transition metal hydrides has been completed. The reaction product of n-butyllithium with biscyclopentadienyltrihydridotantalum in the presence of PMDT is:;Cp(,2)ReLi(.)PMDT has proven to be the most versatile synthetic.;reagent of those studied. The structures of its derivative Cp(,2)ReCH(,3).;and a related compound, Cp(,2)Re(CH(,3))(,2)SO(,3)F, have been determined.;Cp(,2)TaH(,2)((mu)(,3)-Li)((eta)('5)-(eta)('1)C(,5)H(,5))CpTaHLi(.)PMDT(Ta-Li-Ta-Li). Its space group is monoclinic P2(,1)/n with a = 12.450(5) (ANGSTROM), b = 11.394(6) (ANGSTROM), c = 21.564(10) (ANGSTROM), (beta) = 102.38(4)(DEGREES), and z = 4. The bridging lithium replaces the central hydride of the first tantalum moiety and the edge hydride of the second. The second tantalum atom is also coordinated to the chelated lithium atom.;Cp(,2)ReCH(,3) is tetragonal P42(,1)m with a = 8.111(3) (ANGSTROM), c = 7.152(2) (ANGSTROM),(' ).;z = 2; Cp(,2)Re(CH(,3))(,2)SO(,3)F is Pna2(,1) with a = 14.392(6) (ANGSTROM), b = 11.840(8) (ANGSTROM), c = 7.630(5) (ANGSTROM), and z = 4. Deuteration experiments confirm (beta)-hydride activation from rhenium alkyls.;Heterobimetallic species have also been obtained. Cp(,2)ReLi(.)PMDT reacts with (phi)HgBr to form (Cp(,2)Re)(,2)Hg (orthorhombic, Pac2(,1), a = 5.852(3) (ANGSTROM), b = 15.588(7) (ANGSTROM), c = 19.078(10) (ANGSTROM), and z = 4). With CpMo(CO)(,3)Cl, Cp(,2)ReLi(.)PMDT gives CpRe(CO)((mu)-CO)(,2)MoCp(,2) (monoclinic, P2(,1)/c, a = 7.975(3) (ANGSTROM), b = 13.824(7) (ANGSTROM), c = 14.728(8) (ANGSTROM), (beta) = 107.36(3)(DEGREES), and z = 4).(,).;A catalytic amount of Cp(,2)ReLi(.)PMDT reacts slowly with CH(,3)CN to form 2-,6-dimethyl-4-aminopyrimidine. The x-ray structure of this acetonitrile "trimer" has been determined. Its space group is monoclinic P2(,1)/n, a = 7.468(2) (ANGSTROM), b = 7.867(2) (ANGSTROM), c = 11.780(3) (ANGSTROM), (beta) = 99.39(2)(DEGREES), and z = 4. |
