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61.
New equations are derived and implemented for efficient and accurate computation of solvation energy derivatives for the conductor-like polarizable continuum model (C-PCM) and the isotropic integral equation formalism polarizable continuum model (IEF-PCM). Two new molecular surface tessellation procedures GEPOL-RT and GEPOL-AS that generate near continuous potential energy surfaces are proposed for PCM geometry optimization. The combined use of these new techniques leads to efficient and convergent geometry optimizations with the PCMs. 相似文献
62.
The effect of mixing (or “splicing”) extended and minimal basis sets on molecular properties such as geometries, Mulliken charges, dipoles, and internal rotation barriers was studied for several test molecules. The effect is gauged by comparison with full extended basis set calculations. It is found that splicing improves most properties relative to full minimal basis set calculations, and little accuracy is lost if the splicing is done in a judicious manner. 相似文献
63.
Jensen TR Breyfogle LE Hillmyer MA Tolman WB 《Chemical communications (Cambridge, England)》2004,(21):2504-2505
A new Zn alkoxide catalyst supported by an N-heterocyclic carbene rapidly polymerizes D,L-lactide (D,L-LA) to heterotactic enriched poly(lactide)(PLA), while the free carbene and analogs instead yield highly isotactic enriched PLA. 相似文献
64.
P.Waage Jensen 《Chemical physics letters》1977,45(3):415-418
The Raman spectrum of the tetracyanoethylene—hexamethylbenzene EDA complex was recorded using seven lines of an Ar laser and one from a Kr laser. By comparison with spectra recorded of the donor and acceptor molecules separately, it was found that some of the lines of the complex were up to 393 time stronger than the corresponding lines of an uncomplexed molecule. 相似文献
65.
Rapid prototyping of polymer microsystems via excimer laser ablation of polymeric moulds 总被引:1,自引:0,他引:1
Jensen MF McCormack JE Helbo B Christensen LH Christensen TR Geschke O 《Lab on a chip》2004,4(4):391-395
This study presents a novel method for rapid prototyping of polymer microsystems. The method is based on excimer laser ablation of a thermally and mechanically stable polymer, such as PEEK (poly-ether-ether-ketone). A negative of the desired microsystem is laser machined in PEEK, which can then be used directly for hot embossing or injection moulding of a series of prototypes. This approach is very rapid and considerably cheaper than more traditional approaches to toolmaking, while still performing well in terms of reproduction of tool dimensions. The reduction in time and cost for a master tool using this method opens up new possibilities for testing small series in the R&D phase of a microsystem. Finally, two particular applications of the technique are presented. 相似文献
66.
Jensen JO 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(11):2537-2540
The normal mode frequencies and corresponding vibrational assignments of phosphorous tricyanide (P(CN)(3)) are examined theoretically using the Gaussian98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of four types of motion predicted by a group theoretical analysis P-C stretch, CN stretch, P-C[triple bond]C bend, and C-P-C bend) utilizing the C(3v) symmetry of the molecule. A uniform scaling factor was derived for each type of motion. Predicted infrared and Raman intensities are reported. 相似文献
67.
[PdCl(C6H3(OPPri2)2-2,6)] 1 catalyses the coupling of electron-rich, electron-neutral and electron-deficient aryl chlorides with phenylacetylene in the presence of ZnCl2 as cocatalyst to give the products in modest to excellent yields. 相似文献
68.
The first highly diastereo- and enantioselective catalytic 1, 3-dipolar cycloaddition reaction of cyclic nitrones activated by chiral Lewis acids with electron-rich alkenes has been developed. The nitrones, mainly 3,4-dihydroisoquinoline N-oxides, are activated by chiral 3,3'-aryl BINOL-AlMe complexes and undergo a regio-, diastereo-, and enantioselective 1,3-dipolar cycloaddition reaction with especially alkyl vinyl ethers, giving the exo diastereomer of the cycloaddition products in high yield, >90% de and up to 85% ee. The reaction has been investigated under various conditions, and it is demonstrated that the reaction is an attractive synthetic procedure for the introduction of a chiral center in the 1-position of the isoquinoline skeleton. The mechanism of the reaction is discussed on the basis of the assignment of the absolute configuration of the cycloaddition product and theoretical calculations. 相似文献
69.
Conerney B Jensen P Kruger PE MacGloinn C 《Chemical communications (Cambridge, England)》2003,(11):1274-1275
The synthesis and structural characterisation of a novel C3-symmetric tris-bidentate ligand, L, featuring a triphenylamine core appended by pyridylimine coordination sites is reported: 1H NMR compleximetric titration studies with Ag(I) and ESMS indicate the presence of [Ag3L2]3+ species in solution, consistent with the formation of a trinuclear double helicate complex: the Trinity helix. 相似文献
70.
It is demonstrated that the upper and lower values of a two-person, zero-sum differential game solve the respective upper and lower Isaacs' equations in the viscosity sense (introduced by Crandall and Lions (Trans. Amer. Math. Soc. 277 (1983), 1–42). Since such solutions are unique, this yields a fairly simple proof that the game has value should the minimax condition hold. As a further application of viscosity techniques, a new and simpler proof that the upper and lower values can be approximated by the values of certain games with Lipschitz controls is given. 相似文献