Aqua Complexes of [(2-Methoxyethyl)cyclopentadienyl]zirconium Trichloride.

The behavior of [(eta(5):eta(1)-C(5)H(4)CH(2)CH(2)OMe)ZrCl(2)(&mgr;-Cl)](2) (1) toward a variety of solvents, and especially water, was investigated. The bidentate coordination of the C(5)H(4)CH(2)CH(2)OMe ligand is retained in chloroform, dichloromethane, benzene, acetone, thf, and acetonitrile. No stable adducts of 1 with the last three solvents could be isolated. In methanol and water, coordination of the ether side chain is broken; however, removal of solvent retains this coordination and the stable mono adducts (eta(5):eta(1)-C(5)H(4)CH(2)CH(2)OMe)ZrCl(3)(MeOH) and (eta(5):eta(1)-C(5)H(4)CH(2)CH(2)OMe)ZrCl(3)(H(2)O) were isolated. An X-ray structure of the thf solvate of the latter compound was determined: space group P2(1)/c, a = 11.612(1) Å, b = 10.759(2) Å, c = 14.291(2) Å, beta = 105.50(1) degrees, V = 1720.5(4) Å(3), Z = 4, R = 0.062. The intramolecular coordination of the ether side chain is also broken in DMSO, but in this case it is not retained after removal of solvent. A cationic aqua complex [(eta(5)-C(5)H(4)CH(2)CH(2)OMe)ZrCl(2)(H(2)O)(DMSO)(2)](+)Cl(-) crystallized from the solution: space group P&onemacr;, a = 8.297(1) Å, b = 10.097(1) Å, c = 12.883(1) Å, alpha = 71.12(1) degrees, beta = 86.60(1) degrees, gamma = 87.45(1) degrees, V = 1019.0(2) Å(3), Z = 2, R = 0.049. Compound 1 is a Diels-Alder catalyst even under moist conditions.