KINETIC STUDIES ON METHANE REFORMING WITH CARBON DIOXIDE

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Efficient C-F and C-C activation by a novel N-heterocyclic carbene-nickel(0) complex

The NHC-stabilized complex [Ni2(iPr2Im)4(cod)] (1) was isolated in good yield from the reaction of [Ni(cod)2] with 1,3-diisopropylimidazole-2-ylidene (iPr2Im). Compound 1 is a source of the [Ni(iPr2Im)2] complex fragment in stoichiometric and catalytic transformations. The reactions of 1 with ethylene and CO under atmospheric pressure or with equimolar amounts of diphenylacetylene lead to the compounds [Ni(iPr2Im)2(eta2-C2H4)] (2), [Ni(iPr2Im)2(eta2-C2Ph2)] (3), and [Ni(iPr2Im)2(CO)2] (4) in good yields. In all cases the [Ni(iPr2Im)2] complex fragment is readily transferred without decomposition or fragmentation. In the infrared spectrum of carbonyl complex 4, the CO stretching frequencies are observed at 1847 and 1921 cm(-1), and are significantly shifted to lower wavenumbers compared with other nickel(0) carbonyl complexes of the type [NiL2(CO)2]. Complex 1 activates the C--F bond of hexafluorobenzene very efficiently to give [Ni(iPr2Im)2(F)(C6F5)] (5). Furthermore, [Ni2(iPr2Im)4(cod)] (1) is also an excellent catalyst for the catalytic insertion of diphenylacetylene into the 2,2' bond of biphenylene. The reaction of 1 with equimolar amounts of biphenylene at low temperature leads to [Ni(iPr2Im)2(2,2'-biphenyl)] (6), which is formed by insertion into the strained 2,2' bond. The reaction of diphenylacetylene and biphenylene at 80 degrees C in the presence of 2 mol % of 1 as catalyst yields diphenylphenanthrene quantitatively and is complete within 30 minutes.     

Organometallic alkylation of 2-chloro-4,6-dimethoxy-1,3,5-triazine: a study

The reactivity of 2-chloro-4,6-dimethoxy-1,3,5-triazine (1) has been investigated in Pd- or Ni-catalyzed cross-coupling processes with organostannanes, Grignard reagents, organoalanes and organozinc halides. All organometallic reagents considered form new C-C bonds on the heteroaromatic ring and afford the corresponding 2-alkyl-4,6-dimethoxy-1,3,5-triazines in moderate to very good yields. The collected data allows the choice of the alkylating agent as well as the experimental conditions depending on the residue to transfer.     

Heck Arylation of Cyclohexene Promoted by Ultrasonic and Micro wave in Ionic Liquid： a Novel Method of the Synthesis of 3-Naphthylcyclohexene

Palladium catalyzed arylation or vinylation of olefins by aryl halides are well known as the Mizoroki-Heck reaction and have proved to be of genuine synthetic utility for C-C bond formation1. Although a lot of progress has been made in Heck coupling react…     

Orientational preference of two ethylene ligands bound to a nickel atom

CASSCF and CCI calculations have been performed to analyze the bonding in Ni(C₂H₄)₂. Three different relative orientations of the two olefins have been studied. It is found that a structure with D_2d symmetry, where the C-C bonds in the two olefins make a 90 degree angle to each other, gives the lowest energy. A D_2h form, with the two C-C bonds and Ni in the same plane, is 10.3 kcal/ mol higher in energy. The reason for the preference of the D_2d form is analyzed in terms of valence bond theory, and is found to be due to a d ⁸ structure with two simultaneous d bonds. A C _2v form, for which the two nickel olefin bonds make a 103 degree angle to each other and the C-C bonds are parallel to each other, is 32 kcal/mol higher in energy than the D_2d form. The low binding energy of the C _2v form is due to a poor interaction with inefficient sd hybridization.     

蜡相分光光度法研究（Ⅰ）—镍的测定

以镍（Ⅱ）－丁二酮肟－石蜡体系为对象，提出一种新的固相（蜡相）分光光度法，并研究了方法的最佳实验条件；镍量在０～３０μｇ／５０ｍＬ范围内服从比尔定律。本法将显色、富集、分离、测定结合起来，选择性好、灵敏度高。应用于工业废水中镍的测定，结果满意。     

Phosphine σ-sydnonyl complexes of Ni,Pd, and Pt

3-R"-4-Bromosydnones 1 (R" = Me) and 2 (R" = Ph) react with complexes Ì(PR₃)_n (M = Ni, Pd, Pt) to form mononuclear phosphine -sydnonyl d⁸-complexes of trans-configuration MBr(3-R"-sydnon-4-yl)(PR₃)₂: 3, 4 (Ì = Ni, R" = Ph); 5 (M = Pd, R" = Me); 6a (M = Pd, R" = Ph); 7 (M = Pt, R" = Ph). In the reaction of bromosydnone 2 with Pd(PPh₃)₄, the cis-complex PdBr(3-Ph-sydnon-4-yl)(PPh₃)₂ (6b) is formed initially; 6b rearranges in solution to give trans-complex 6a. On heating in THF, complex 6a is converted into the binuclear [PdBr(3-phenylsydnon-4-yl)(PPh₃)]₂ complex (8). The reaction of 4-chloromercurio-3-phenylsydnone (10) with Ni(PEt₃)₄, Pd(PPh₃)₄, and Pt(PPh₃)₄ gives mononuclear NiCl(3-phenylsydnon-4-yl)(PEt₃)₂ complex (11), binuclear [PdCl(3-phenylsydnon-4-yl) (PPh₃)]₂ complex (14), and cis- and trans-bimetallic PtCl(3-phenylsydnon-4-ylmercurio)(PPh₃)₂ complexes 15a and 15b, respectively. UV irradiation of 15a and 15b in a benzene solution induces redox demercuration to yield the PtCl(3-phenylsydnon-4-ylcarbonyl)(PPh₃)₂ complex (16). In carbonylation of complexes 3, 6, and 7, CO insertion into the M--C bond occurred to form the corresponding acyl derivatives MBr(3-phenylsydnon-4-ylcarbonyl)(PR₃)₂ (17--19).     

双波长K系数-标准加入-导数分光光度法同时测定重油中的钴镍

本文提出了一种同时测定两组分混和物的新方法，即双波长Ｋ系数－标准加入－导数分光光度法，该法同时进行两组分的标准加入，以两个组分的峰值波长为测定波长，又互为参比波长，利用Ｋ系数法以一套吸光度数据同时完成两个组分的测定。本文以ＯＰ－５－Ｂｒ－ＰＡＤＡＰ为显色体系，同时测定了重油中的钴、镍，结果令人满意。本方法简便，灵敏度高。     

NiW/γ-Al2O3加氢催化剂化学吸附性质的研究

采用脉冲色谱法测定了噻吩在硫化态NiW/γ-Al2O3催化剂上化学吸附过程中热力学函数的变化,并与噻吩加氢脱硫(HDS)反应活性进行了关联.结果表明,噻吩在硫化态NiW/γ-Al2O3催化剂上的吸附不能太强,催化剂中的Ni可以降低噻吩在催化剂表面上的吸附强度,增加HDS反应活性中心的数目.从H2在硫化态NiW/γ-Al2O3催化剂上吸附后的程序升温脱附实验结果发现,H2在硫化态催化剂上有两种吸附态,高温脱附所对应的吸附态与HDS反应有关.     

高分子网络法制备纳米NiO超细粉的研究

Superfine NiO powders，15～50nm ca.， with single phase and uniform particle size have been prepared from Ni(NO₃)₂ by a polymer-network gel process. The results demonstrate that the distribution of the particle sizes of final oxides depends on the heated temperature，time and concentration of original nickel nitrate solution. The control of particle size of nano-NiO powders can be realized by the control of the condition of the process.