摘要:

AbstractDimerization of isobutene in liquid state to form high‐octane value gasoline components was investigated over a homemade novel ion exchange resin, SPPESK, which shows high activity and selectivity in isobutene dimerization under mild condition

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210602

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

年代:2003

数据来源: WILEY

摘要:

AbstractA series of novel chiral C2‐symmetric bis (oxazoline) ligands have been synthesized. The copper and magnesium complexes, preparedin situfrom copper (II)‐triflate or magnesium triflate with the new enantiopure oxazoline ligands, were evaluated as chiral catalysts in the enantioselective Diels‐Alder reaction of cyclopentadiene with JV‐crotenoyl‐oxazolidin‐2‐one. Primary results showed that diastereoselectivity up to 94% and enantioselectivity up to 68%eeforendoproducts were observed respectively with

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210603

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

年代:2003

数据来源: WILEY

摘要:

AbstractThep‐tert‐butyl calix[4] arene derivatives la with uracils and lb with adenines at the lower rim were synthesized. The Interaction between la and lb in CDCl3 solution was demonstrated by1H NMR spectra. The interfacial molecular recognitions of la and lb for the complementary nucleosides in aqueous subphases were investigated by Langmuir‐Blodgett tech

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210604

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

年代:2003

数据来源: WILEY

摘要:

AbstractTwo types of polysiloxanes, which contain both C60moieties and carbazolyl groups in the side chains with a difference in the numbers of the reacting site on C60molecules, were synthesized and their fluorescent properties were studied to distinguish the role of C60in the luminescent polymers. Our results demonstrated that when C60moieties are bonded to the polymers as multisubstituents but not linked to the luminescent moieties directly, the luminescence of the resultant polymers were still very strong instead of quenching, even the substituted degree is only 1.01.

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210605

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

年代:2003

数据来源: WILEY

摘要:

AbstractThe research for the new algorithm is in the forward position and an issue of general interest in chemometrics all along. A novel chemometrics method, Chemical Ant Colony Algorithm, has first been developed. In this paper, the basic principle, the evaluation function, and the parameter choice were discussed. This method has been successfully applied to the fitting of nonlinear multivariate function and the optimization of test conditions in chrome‐azure‐S‐Al spetrophotometric system. The sum of residual square of the results is 0.0009, which has reached a good convergence r

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210606

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

年代:2003

数据来源: WILEY

摘要:

AbstractThe equilibrium geometries and UV‐visible spectra of a series of donor‐C60molecules were obtained by means of the AM1 and INDO/CI method, on the basis of accurate geometric and electronic structures. The nonlinear second‐order optical polarizabilities were calculated using the method INDO/SDCI combined with the Sum‐Over‐States (SOS) expression. The calculated β (λ=1.34μm) values are 28.81, 48.56, 57.33, 66.99, 70.85, 85.84, and 142.14 (× 10–30esu) for the molecules A, B, C, D, E, F and G, respectively. The frontier orbitals were plot for the representative molecules in order to exhibit the intramolecular charge transfer. The results indicate that introduction of thienylethylene can enhance the NLO response and the dimethylaniline‐substituted dithienyl‐ethylene‐C60(molecule G) possesses the largest NLO second‐order optical polarizability. The large β values can be attributed to the charge transfer between the substituents and C60, as well as within the three‐dimensiona

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210607

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

年代:2003

数据来源: WILEY

摘要:

AbstractThe ionic and neutral state potential energy surfaces (PESs) of Na +I2collision system have been calculated on QCISD(T) level by usingab initiomethod. The location and depth of the potential well, the collision radius and their fine structures have been analyzed at the equilibrium geometry of I2molecule. The electronic transfer probabilities are also calculated in terms of Lan‐dau‐Zener model. The lifetime of scattering resonance state is evaluated by the uncertainty principle. All the results have been compared with those obtained according to the Aten‐Lanting‐Los PES and Fen

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210608

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

年代:2003

数据来源: WILEY

摘要:

Abstract2‐{[4‐(N‐Hexadecyl‐N‐methylamino) phenyl] methylene}‐propanedinitrile (HMAPN) with typical donor‐#‐acceptor (D‐#‐A) structure was synthesized. It could be easily assembled into stable films by LB technique. The photophysical properties of HMAPN were investigated in solution and on LB films. The photoelectric properties of HMAPN were examined and the anodic photocurrent of the ITO electrode modified by the monolayer LB film of HMAPN was measured as 835 nA/cm2under the white light of 218.2 mW/cm2without bias voltage. The effects of light intensity, bias voltage on the photocurrent were discussed. The possible mechanism of the photocurrent

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210609

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

年代:2003

数据来源: WILEY

摘要:

AbstractTrans‐4‐(N, N'‐dimethyl amino)‐4′‐(N‐hydroxyethyl‐N'‐ethyl amino) stilbene (DMAHAS) has been synthesized and characterized by1H NMR spectra, ER spectra and elemental analysis. Linear absorption, single‐photon induced fluorescence and two‐photon induced fluorescence were experimentally studied. This new dye has a moderate two‐photon absorption cross‐section of σ 2 = 0.91 × 10–46cm4· s/photon at 532 nm by using an open aperture Z‐scan technique. The result indicates that DMAHAS shows a strong two‐photon induced blue fluorescence of 432 nm when pu

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210610

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

年代:2003

数据来源: WILEY

摘要:

AbstractThe electrolysis of catechol was studied in the pH values of 1 to 10. The results from the rotating ring‐disk electrode (RRDE) experiments show that at low pH values, the electrochemical polymerization of catechol was performed by one step, and at higher pH values, the electrochemical polymerization of catechol was carried out by two steps,i.e.oxidation of catechol and followed by polymerization. The intermediates generated at the disk were detected at the ring electrode in the ring potential region of‐0.2to 0 V (vs. Ag/AgCl). One of reasons for the decrease in the ratio ofirtoidwith increasing the ring potential is caused by formation of positively charged intermediates at the disk electrode. This ratio increases with increasing the rotation rate of the RRDE, which indicates that the intermediates are not stable. A shielding effect during polymerization of catechol was observed when the ring potential was set at 0.1 V (vs. Ag/AgCl). The electron spin resonance (ESR) of polycatechol shows that polycatechol possesses unpaired electrons. The images of polycatechol films synthesized at different conditions are descri

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210611

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

年代:2003

数据来源: WILEY