摘要:

AbstractA nickel catalyst was modeled with ligand L2, [NH = CH—CH = CH—O]−, which should have potential use as a syndiotactic polyolefin catalyst, and the reaction mechanism was studied by theoretical calculations using the density functional method at the B3LYP/ LANL2MB level. The mechanism involves the formation of the intermediate [NiL2Me]+, in which the metal occupies a T‐shaped geometry. This intermediate has two possible structures with the methyl grouptranseither to the oxygen or to the nitrogen atom of L2. The results show that both structures can lead to the desired product via similar reaction paths, A and B. Thus, the polymerization could be considered as taking place either with the alkyl group occupying the positiontransto the Ni—O ortransto the Ni—N bond in the catalyst. The polymerization process thus favors the catalysis of syndiotactic polyolefins. The syndiotactic synthesis effects could also be enhanced by variations in the ligand sub‐stituents. From energy considerations, we can conclude that it is more favorable for the methyl group to occupy thetrans‐Oposition to form a complex than to occupy thetrans‐N position. From bond length considerations, it is also more favoured for ethene to occupy thetrans‐Oposition than to occupy

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210502

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractCrystal structures of new nitronyl nitroxide derivatives 1, 2 and 3 were determined with X‐ray diffraction analysis: 1, monoclinic,C2/c, a= 1.2404(5) nm,b= 0.9730(5) um,c= 2.7049(10) ran, β = 98.189(15)°,V= 3.2315(24) nm3, Z = 8; 2, or‐thorhombic,Pbca, a= 0.61262(2) nm,b= 1.11426(6) nm,c= 2.30543(13) nm,V= 1.57373(13) nm3,Z= 4; 3, monoclinic,P2(1)/n, a=0.64253(4) nm,b=2.55003(17) nm,c= 1.15497(6) nm, β = 95.000(3)°,V= 1.8852(2) nm3,Z= 4. Their magnetic properties were measured with SQUID and analyzed based on their crystal structures with simple singlet‐triplet, modified one dimensional antiferromagnetic chain and modified singlet‐triplet models respectively: 1,J/kb= −2.5 K; 2,J/kb= 7.8 K, θ = 2.8 K; 3,J/kb= −0.

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210503

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

Abstractβ‐Cyclodextrin was pretreated by methylaluminoxane (MAO) and subsequently reacted with 8‐aminoquinoline nickel dichloride complex to yield the supported catalyst, which was characterized by ICP, IR and XPS methods. Using MAO as cocatalyst, the catalytic activity of this supported catalyst was investigated at various reaction temperature and AI/Ni molecular ratio. The results showed that, despite possessing a number of polar groups, the supported catalyst displayed relatively high activity over 1 × 105g ethylene/(mol Ni·h) under mild cond

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210504

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractWater‐soluble polyether phosphites alkyl polyethylene glycolo‐phenylene phosphite (APGPPs) were easily prepared via alcoholysis of phosphorus chloride with polyoxyethylene alkyl ether. With appropriate HLB (hydrophile‐lypophile balance), the phosphites possess clear cloud points below 100 °C. Addition of some inorganic salts decreases cloud points of the phosphites. When the phosphites have long polyether chain binding to short‐chain alkyl group, their cloud points could be extrapolated from figure of dependence of cloud points on addition of inorganic salts. Utilizing octylpolyglycol‐phenylene‐phosphite (OPGPP) (APGPP, R: Octyl)/Rh complex formedin situas catalyst, over 90% conversion of 1‐decene was obtained, avoiding the limitation of water insolubility of substrates. Preliminary results indicated that micellar catalysis and thermoregulated phase‐transfer catalysis (TRPTC) coexist in the reaction system. Below cloud point, micellar catalysis induced by polyether phosphites may be existed. When temperature is increased to above cloud point of the phosphites, this reaction works mainly in TRPTC. The catalysts could be easily separated by simple decantation, but followed by considerable loss in activity after three successive reaction runs. Preliminary results indicated hydrolysis of OPGPP happened during the reaction, which may explain for the bad loss in activity. The catalyst was reused up to seven times without clear decrease in activity when OPGPP/Rh ratio was

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210505

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractA novel complex [Cu(NnpPy)2(HlTCB)(H1O)]·2H2O (NITpPy = 2‐(pyrid‐4′‐yl)‐4,4,5,5‐tetramethyl‐1, 3‐dioxoimidazoline; H2TCB = 1, 5‐dicarboxybenzene carboxylic‐2, 4‐diacid) has been synthesized and characterized by X‐ray crystallography analysis. The crystal structure consists of infinite chains of Cu‐(NITpPy)2(H2O) units linked by H2TCB ligands. The complex crystallizes in triclinic system with space groupPI. Crystal data:a= 1.0594(2) nm,b= 1.3830(3) nm,c= 1.5551(3) nm,a= 67.75(3)°, β = 89.83(3)°, γ = 70.54(3)°. The variable magnetic susceptibility studies lead to magnetic coupling constant values ofJ1= −11.18 cm

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210506

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractTwo new bipyridine ligands with intramolecular charge transfer (ICT) transition as the lowest excited state were designed and synthesized. Upon addition of metal ions, particularly Zn2+, the absorption and emission spectra experience great changes. The binding constants towards Zn2+are 1.27 × 105L/mol and 1.66 × 105L/mol for ligands 1 and 2, respectively. The strong binding affinity and high selectivity make them attractive for application as fluorescence sensors for Zn2

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210507

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractThe Schiff base‐containing pendant monoaza crown ether HL1, HL2, HL3and HL4have been synthesized by condensation of salicylaldehyde withN‐(4‐aminoaryl) monoaza crown ethers, which were prepared conveniently from 4‐nitro‐N, N‐di(hydroxyethyl) aniline or 4‐nitrobenzyl chloride via cyclization or condensation and reduction. The structures of HL1—HL4were verified by1H NMR, IR spectra, MS and elemental analysis. Moreover, the oxygenation constants (KO2) and thermodynamic parameters (δH0and δS0) of their cobalt(II) complexes were determined in the range of −5 °C to 25 °C, and the effect of crown ring bonded to a Schiff base on the dioxygen affinities of cobalt(II) complexes was also observed as compared to the uncrow

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210508

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractA novel compound (H2en)5[CoMo12O50P8(OH)12] ·2H2O (1) (en = H2NCH2CH2NH2) has been hydrothermally synthesized and characterized by elemental analyses, IR, EPR, XPS spectra and single‐crystal X‐ray diffraction analyses. Compound 1 crystallizes in a triclinic system, space groupPi, witha= 1.1863(2) nm,b= 1.3361(3) nm, c = 1.3783(3) nm,a= 88.13(3)°, β = 70.09(3)°, γ = 65.24(3)°,V= 1.8497(6) mn3, andR= 0.0417. The basic building blocks of compound 1 are|Mo6P4[clusters forming dimers through the|CoO6] octahedra. Compound 1 exhibits an unusual three‐dimensional framework with tunnels owing to the extensive hydrogen bonding interactions between the dime

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210509

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractTwo copper complexes [Cu(TTA)2(4,4′‐azpy)] (1) and [Cu‐(TTA)2(3,3′‐azpy)] (2) (HTTA = 1,1,1‐trifluoro‐3‐(2‐thenoyl)‐acetone, 4,4′‐azpy = 4,4′‐azobispyridine, 3,3′‐azpy = 3,3′‐azobispyridine) were synthesized and characterized. The crystal structures were determined by X‐ray diffraction analysis. The crystal 1 belongs to triclinic with space groupP1,a= 0.8515(2) nm,b= 0.9259(2) nm,c= 0.9468(2) nm,a= 66.126(9)°, β = 79.667(9)°, γ = 90.13(1)°, Z = 1,V= 0.6692(2) nm3,Dc= 3.425 g/cm3, γ = 2.113 mm−1,F(000) = 694,R1= 0.0594,wR2= 0.1499. The crystal 2 belongs to monoclinic with space groupP21/c, a= 1.0661(2) nm,b= 1.4296(3) ran,c= 1.0041(3) nm, β = 114.50(3)°,V= 1.3926(5) nm3, Z = 2,Dc= 1.646 g/ cm3, μ = 1.015 mm−1, F(000) = 694,R1, = 0.0535,wR2= 0.1113. In the crystals of complexes 1 and 2, the copper atoms have distorted octahedral symmetry. The two compounds possess very similar one‐dimensional linear chains linked throug

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210510

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractA penta‐coordinated Cu(II) complex with mixed ligands 4, 4′‐bipyridine (4,4′‐bpy) and 2‐pyrazine‐5‐carboxylate anion (2‐pzc), [Cu(4,4′‐bpy)(2‐pzc)(H2O)]CIO4·HzO (1), has been solvothermally synthesized and characterized. Complex 1 crystallizes in the monoclinic space groupP21/nwitha= 0.82996(2) nm,b= 1.58156(5) nm,c= 1.53837(1) nm, β = 103.536(2)°,V= 1.96322(8) nm3,Mr= 478.30, Z = 4,Dc= 1.618 g/cm3, finalR= 0.0544 andwR= 0.1487. The Structure of 1 indicates that the central Cu(II) atom is penta‐coordinated by two N atoms from two 4,4′‐bpy ligands, and one N atom and one oxygen atom of the 2‐pzc ligand in the equatorial plane, and one oxygen atom of the coordinated water molecule at the axial position. The coordination geometry of Cu(II) atom could be considered as a slightly distorted square‐pyramidal environment. The 4, 4′‐bpy ligands bridge the Cu(II) centers to form a one‐dimensional chain, and 2‐pzc acts as a terminal chelated ligand, and #±# interaction between the pyrazine rings of 2‐pzc ligands of adjacent chains links the chains into a 2D sheet. Furthermore, the hydrogen bonds among the oxygen atoms of the uncoordinated water molecules and the N atoms and O atoms of 2‐pzc ligands and the oxygen atoms of the coordinated water molecules link the

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210511

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY