13282-39-8Relevant academic research and scientific papers
Lactide polymerization with chiral β-diketiminate zinc complexes
Drouin, Frederic,Oguadinma, Paul O.,Whitehorne, Todd J. J.,Prudhomme, Robert E.,Schaper, Frank
, p. 2139 - 2147 (2010/07/03)
N,N--Di(S-phenylethyl)-2-amino-4-iminopent-2-ene, S,S-nacnac CH(Me)PhH, 1a, and N,N--dibenzyl-2-amino-4-iminopent-2-ene, nacnacBnH, 1b, react with ZnEt2 to form the corresponding nacnacZnEt complexes 2a and 2b. Neither complex is reactive with 2-propanol or methyl lactate to produce the corresponding alkoxide complexes. In reactions with 2b, ligand redistribution occurs and nacnacBn2Zn was obtained. Reaction of 1a and 1b with Zn(N(SiMe3)2) 2 yielded nacnacZnN(SiMe3)2, 6a and 6b. From further reactions with 2-propanol nacnacZnOiPr, 7a and 7b, were obtained. Both complexes were catalytically active for polymerization of rac-lactide with apparent first-order rate constants of kapp = 0.013-0.019 min -1 and 0.019-0.038 min-1 for 7a and 7b, respectively. Obtained polymers were highly heterotactic, with Pr = 0.84-0.87 (7a) and 0.65-0.71 (7b). Analysis of remaining monomer after 75% conversion showed negligible ee and indicates that chiral 7a does not show enantioselectivity in rac-lactide polymerization. Complex 7a, but not 7b, catalyzes unselective transesterification of the polymer during and after polymerization. PLA microstructures in polymerizations with 7b were independent of temperature (23 or 0 °C) or monomer/catalyst ratio (100:1 to 400:1). However, slightly higher Pr values were obtained in the presence of 10-100 equiv of MeCN or pyridine. Complexes nacnacBn2Zn, 2b, 6b, and 7a were characterized by an X-ray diffraction study.
METAL OXIDE COATINGS
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Page/Page column 5, (2009/03/07)
Compounds of formula I may be hydrolyzed to produce metal oxides wherein M is Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, La, Hf, Ta, W, Re, Os, Ir, Pt, Hg, Tl, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, U, or Pu; X is O1/2 or OR; R is alkyl; R1, R2, R3, R4, R5, R6, and R7 are independently H, alkoxy, C1-C10 alkyl, phenyl or R10, R11, R12, R13, R14 and R15 are independently C1-C10 alkyl or phenyl; n is equal to the the value of the oxidation state of M minus q; m and p are independently 0 or an integer from 1 to 5; and q is 0, 1, 2, or 4; with the proviso that when q is 1, X is OR; and when q is 2, X is O1/2, and M is V, Cr, Mn, Fe, As, Nb, Mo, Tc, Ru, Sb, Ta, W, Re, Os, Ir, Pt, Bi, Th, U, or Pu; and when q is 4, X is O1/2, and M is Cr, Mo, W, Ru, Re, Os, U, or Pu. Articles comprising at least one metal oxide are fabricated by coating a substrate with at least one compounds of formula I before hydrolyzing, and/or heating the compound at a temperature ranging from about 50° C. to about 450° C.
