Meisu Zhou

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 structural study of an unsymmetrical aliphatic benzamidinato ligand and its use in the formation of selected Cu(I), Mg(II) and Zr(IV) complexes

The reaction of a Et2O solution of LiN(Cy)SiMe3 (Cy = cyclohexyl) with PhCN in the presence of the Lewis-base donor tetrahydrofuran (THF) or Me2N(CH2)2NMe2 (TMEDA) gave the THF- or TMEDA-solvated unsymmetrical aliphatic lithium benzamidinato compound [{PhC(NCy)(NSiMe3)}Li(THF)]2 (1) or [{PhC(NCy)(NSiMe3)}Li(TMEDA)] (2). Treatment of LiN(Cy)SiMe3 with PhCN in diethyl ether, and further with CuCl, MgBr2(THF)2 or ZrCl4 at a ratio of 1:1, 2:1 and 3:1 allowed the formation of novel metal complexes [{PhC(NCy)(NSiMe3)}Cu]2 (3), [{PhC(NCy)(NSiMe3)}2Mg(OEt2)] (4) and [{PhC(NCy)(NSiMe3)}3ZrCl] (5), respectively. The X-ray structures of complexes 1–4 are presented. Complex 5/MAO system allows the moderate polymerization of ethylene.

Organoamido zirconium(IV) and titanium(IV) complexes and their catalysis towards ethylene polymerization

The reaction of PhN(Li)SiMe3 with 2 equiv. of dimethylcyanamide with further addition of 2 equiv. of CpTiCl3 led via Me3SiCl elimination to dinuclear titanium(IV) compound 1. The reaction of DippN(Li)SiMe3 with 1 equiv. of dimethylcyanamide with further addition of 1 equiv. of CpTiCl3 afforded centrosymmetric dimeric titanium(IV) compound 2 and mononuclear 3 with the elimination of Me3SiCl. The zirconium(IV) compound 4 was obtained by the addition reaction of PhN(Li)SiMe3 with 2 equiv. of dimethylcyanamide and metathesis reaction with ZrCl4. X-ray diffraction studies of 1–4 establish the dinuclear titanium(IV) structure in 1, half-titanocene of 2 and 3, and a propeller-like complex fragment of 4. Complexes 2 and 4 show moderate or high activities in the polymerization of ethylene upon activation with methylaluminoxane (MAO).

2‐tert‐Butyl‐4‐piperidino‐β‐diket­imine

The title compound, C12H23N3, was prepared and its crystal structure was determined. The five-membered N—C=C—C=N fragment is planar.

Crystal structure of [1-(2,6-diiso-propyl-phen-yl)-2,4-bis-(di-methyl-amino)-5-tri-methyl-silyl-1,3,5-tri-aza-penta-dienyl-κ(2) N (1),N (5)](tri-phenyl-phosphane-κP)copper(I).

The title complex, [Cu(C21H38N5Si)(C18H15P)], was obtained from the one-pot reaction between (Dipp)N(Li)SiMe3 (Dipp = 2,6-diisopropylphenyl), Me2NCN, CuCl and PPh3. The CuI atom has a distorted trigonal–planar coordination sphere. The triazapentadienyl ligand acts as a κ2-donor. The N—Cu—N bond angle is 95.88 (14)°. In the triazapentadienyl fragment, the C—N bond lengths are in the range 1.328 (5)–1.349 (5) Å, which indicates delocalization of the π-electrons in the NCNCN system.

CCDC 883524: Experimental Crystal Structure Determination

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catena-Poly[[(N,N-di­methyl­cyanamide-κN)lithium]-μ3-bromido]

The title complex, [LiBr(C3H6N2)]n, is the unexpected product of a reaction beteween (Dipp)N(Li)SiMe3 (Dipp = 2,6-diisopropylphenyl), Me2NCN and CuBr. The compound is a one-dimensional polymer with a step structure derived from the association of inversion dimers, formed by bromido ligands bridging two Li+ cations, each of which carries a dimethylcyanamide ligand. The planar (LiBr)2 unit of the polymer core has a regular rhombic shape [Li—Br—Li 77.55 (16)° and Br—Li—Br 102.45 (16)°]. These (LiBr·NCNMe2)2 dimers represent the repeat unit of a polymer system propagated by additional Br—Li and Li—Br bonds generating an infinite step structure along the a-axis direction.

Bis(2-methyl­phenyl­amino)phenyl­borane

In the title compound, C20H21BN2, the B and N atoms show trigonal planar geometry. The B—N bond lengths of 1.4177 (19) and 1.418 (2) A indicate covalent partial double bonds.