SYNTHESIS AND CHARACTERIZATION OF CP(2)AS TERISK-M(DAD) COMPLEXES (M=Y OR LA) - MOLECULAR-STRUCTURE OF 2)ASTERISK-Y[N(C6H4-4-ME)=C(PH)C(PH)=N(C6H4-4-ME)]

The treatment of (eta(5)-C(5)Me(5))(2)La(mu-Cl)(2)K(dme)(2) (3) with a n equimolar amount of Na-2(DAD)[DAD=(Ph)N=C(Ph)C(Ph)=N(Ph)] in the pre sence of DAD or with two equivalents of Na(DAD) results in the formati on of the ionic complex [Na(DAD)][(eta(5)C(5)Me(5))(2)La(DAD)] (4), wh ich has been characterized by IR and NMR spectroscopy. Complex 4 exhib its dynamic NMR spectra indicating rapid migration of the (eta(5)-C(5) Me(5))(2)La unit from one side of the reduced DAD ligand to the other. (eta(5)-C(5)Me(5))(2)Y(mu-Cl)(2)Li(OEt(2))(2) (5) reacts with Na(DAD) [DAD=(Me-4-C6H4)-N=C(Ph)C(Ph)=N(Me-4-C6H4)] to yield dark-red crystals of the complex (eta(5)-C(5)Me(5))(2)Y(DAD) (6). Complex 6 is monoclin ic, of space group C2/c (No. 15), with Z = 4, with a = 1345.2(3), b = 1702.9(2) and c = 1811.3(2) pm and with beta = 106.73(1)degrees. The s tructure was refined to R = 0.040 for 2399 observed reflections (F-0 > 4 sigma(F-0)). The DAD ligand in 6 is reduced to the radical anion an d forms a planar five-membered Y(N-C-C-N) ring.