Synthesis of bis-cyclopentadienyl, bis-indenyl and mixed-ring indenyl halides of tungsten

A convenient route to the tungstenocene derivatives Cp2WX2 from CpW(eta(3)- C5H5)(CO)(2) via [CP2W(CO)(2)](2+) or [Cp2W(NCMe)(CO)](2+) is described. Si milar preparations, starting from CpW(eta(3)-C9H7)(CO)(2), lead to the mixe d-ring indenyl analogues of tungstenocene, IndCpWI(2) [Ind = (eta(5)-C9H7)] . A stepwise route to bis-indenyl derivatives of tungsten is reported, base d on the novel W(IV) complex IndWCl(3)(CO)(2) which is synthesized by the r eaction of IndW(eta(3)-C3H5)(CO)(2) with HCl gas in dichloromethane. Treatm ent of IndWCl(3)(CO)(2) with KInd in THF gives IndW(eta(3)-Ind)(CO)(2) in h igh yield. This complex is a convenient starting material for the preparati on of some bis-indenyl analogues of tungstenocene, Ind,WI,. The molecular s tructures of [IndW(eta(4)-C5H6)(CO)(2)]BF4 (7a) and [IndCpWH(CO)]BF4 (7b) w ere characterized by single-crystal X-ray diffraction. The crystals belong to the triclinic and monoclinic space group P (1) over bar and P2(1)/c with a = 729.98(3) and 715.0(3) pm; b = 783.06(3) and 1484.0(6) pm; c = 1419.20 (4) and 1389.2(6) pm; alpha = 100.210(2) and 90 degrees; beta = 104.557(2) and 99.18(3)degrees; gamma =93.441(2) and 90 degrees, respectively. The fin al refinements of 7a and 7b converged at R-1 = 0.0236 and 0.0680; wR(2) = 0 .0581 and 0.1378, respectively. (C) 1999 Elsevier Science S.A. All rights r eserved.