Syntheses of Tantalum(V) Complexes Containing Tetramethylpyrrolyl, Pyrrolyl, and Indolyl Ligands.
The reaction of TaMe(3)Cl(2) with the lithium salt of tetramethylpyrrole (Li-TMP) led to the formation of (eta(5)-TMP)TaMe(3)Cl (1). Reactions of 1 with a series of anionic ligands have been carried out to form products of the formula (eta(5)-TMP)TaMe(3)X, where X = SR, Me, pyrrolyl, or indolyl. Crystals of (eta(5)-TMP)TaMe(3)(indolyl) (5), were isolated in space group P2(1)/c with a = 8.957(2) Å, b = 28.540(6) Å, c = 14.695(3) Å, beta = 99.40(3) degrees, V = 3706.1(14) Å(3), and Z = 8. The structure confirmed the eta(5)-bonding mode of the tetramethylpyrrolyl ligand and the eta(1)-N-coordination mode of the indolyl ligand.The derivatives (eta(5)-TMP)TaMe(3)X showed limited stability, and decomposition products which formed in toluene solutions at room temperature have been identified in some cases. The reaction of (eta(5)-TMP)TaMe(3)(pyrrolyl) with hydrogen (2-3 atm) in benzene-d(6) solution at room temperature was studied. The stoichiometric formation of cyclohexane-d(6) by hydrogenation of an equivalent of solvent was confirmed by (1)H and (13)C NMR and gas chromatographic/mass spectroscopic data. The characteristics and scope of the room temperature arene hydrogenation process are discussed.
Parker
Keith G.
KG
Department of Chemistry and Biochemistry, Univeristy of Colorado, Boulder, Colorado 80309.
Noll
Bruce
B
Pierpont
C. G.
CG
Rakowski DuBois
M.
M