Linhong Weng

Synthesis and crystal structures of novel β-diketiminato-lithium, iron, cobalt, nickel, zirconium complexes and their catalytical behaviors in polymerization of ethylene

Treatment of azaallyl-lithium [ LiN(R)C(Bu t )C HR] with equal portion of 1-piperidinecarbonitrile gave mix-substituted bdiketiminato-lithium 2. Double ratio of 2 with FeCl2, CoCl2 and NiCl2/6H2O yielded the b-diketiminate iron 3, cobalt 4, nickel 5 ,o r equivalent of ZrCl4 led to zirconium complex 6, respectively. The structural features of these complexes were described, and the catalytical behaviors of the complexes 3 � /6 for the polymerization of ethylene were investigated. # 2002 Elsevier Science B.V. All rights reserved.

Synthesis and Structures of Selected Triazapentadienate of Li, Mn, Fe, Co, Ni, Cu(I), and Cu(II) using 2,4-N,N'-Disubstituted 1,3,5-Triazapentadienate Anions as Ancillary Ligands : [N(Ar)C(NMe2)NC(NMe2)-N(R)]-(Ar = Ph, 2,6-iPr2-C6H3; R = H, SiMe3)

Addition reaction of ArN(SiMe 3)M (Ar = Ph or 2,6 - (i) Pr 2-C 6H 3 (Dipp); M = Li or Na) to 2 equivalents of alpha-hydrogen-free nitrile RCN (R = dimethylamido) gave the dimeric [M{N(Ar)C(NMe 2)NC(NMe 2)N(SiMe 3)}] 2 ( 1a, Ar = Ph, M = Li; 1b, Ar = Ph, M = Na; 1c, Ar = Dipp, M = Li). 1d was obtained by hydrolysis of 1c at ambient temperature. Treatment of a double ratio of 1a or 1b with anhydrous MCl 2 (M = Mn, Fe, Co) yielded the 1,3,5-triazapentadienato complexes [M{N(Ph)C(NMe 2)NC(NMe 2)N(SiMe 3)} 2] (M = Mn, 2; Fe, 3; Co, 4) and with NiCl 2.6H 2O gave [M{N(Ph)C(NMe 2)NC(NMe 2)N(H)} 2] (M = Ni, 5). Treatment of an equiv of 1c with anhydrous CuCl in situ and in air led to complexes [{N(Dipp)C(NMe 2)NC(NMe 2)N(SiMe 3)}CuPPh 3] 6 and [Cu{N(Dipp)C(NMe 2)NC(NMe 2)N(H)} 2] 7, respectively. 1c, 1d, and 2- 7 were characterized by X-ray crystallography and microanalysis. 1c, 1d, 5, and 6 were well characterized by (1)H, (13)C NMR, 1c by (7)Li, and 6 by (31)P NMR as well. The structural features of these complexes were described in detail.

Synthesis and structures of novel chiral lithium amidinates and mono- and di-lithium (1R,2R)-(−)-1,2-(NHSiMe3)2C6H10

Four lithium salts derived from (1R,2R)-1,2-diaminocyclohexane are described. After the resolution of 1,2-diaminocyclohexane (DACH), (1R,2R)-(−)-1,2-(NHSiMe3)2C6H10 (1) was prepared from the (R,R) enatiomer by reaction with LiBun and Me3SiCl. Treatment of 1 with one equiv. of LiBun gave the single lithium salt (1R,2R)-(−)-1-Li(NSiMe3)-2-(NHSiMe3)C6H10 (2). Double deprotonation of 1 with two equiv. of LiBun yielded the dilithium salt Li2[(1R,2R)-(−)-1,2-(NSiMe3)2C6H10] (3). The addition reaction of 2 or 3 with PhCN gave (1R,2R)-(−)-1-Li[NC(Ph)N(SiMe3)]-2-(NHSiMe3)C6H10 (4) and Li2[(1R,2R)-(−)-1,2-{NC(Ph)N(SiMe3)}2C6H10] (5) respectively. Crystallographic studies and comparison of these lithium salts with β-diketiminates exhibit some noteworthy features.