Inorganic Chemistry, Vol.36, No.20, 4372-4380, 1997
B-benzene in a heterobimetallic fluoroalkoxide: CH...FC hydrogen bonding?
The syntheses of Lewis base-free [Pb(HFIP)(2)] (HFIP = OCH(CF3)(2)) and [Li(HFIP)] are described. [Pb(OR)(2)] (OR = (OPr)-Pr-i or HFIP) reacts with [LiOR] to give [PbLi(OR)(3)](n), which sublimes intact at a temperature lower than the sublimation temperatures of its constituent alkoxides. By multinuclear solution NMR spectroscopy, evidence for more than one [PbLi(OR)(3)] oligomer is found. The HFIP heterobimetallic species crystallizes from benzene as a dimer (i.e., n = 2) with 1 equiv of C6H6 in its lattice, while the nonfluorinated analog does not. The numerous CH ... FC distances observed by a crystallographic study approach the sum of the van der Waals radii of H and F. Crystallographic data (P (1) over bar at -172 degrees C) for [Pb2Li2(HFIP)(6)(C6H6)]: a = 10.020(4) Angstrom, b = 12.367(5) Angstrom, c = 9.784(4) Angstrom, alpha = 106.03(2)degrees, beta = 107.72(2)degrees, and gamma = 105.36(2)degrees with Z = 1.