Zobrazeno 1 - 10
of 479
pro vyhledávání: '"Norman L. Allinger"'
Autor:
Jenn-Huei Lii, Norman L. Allinger
Publikováno v:
Journal of the Mexican Chemical Society. 53
A broad diverse test set of alkanes and cycloalkanes previ- ously studied with MM4 calculations has had the heats of formation calculated by several different quantum mechanical methods: Hartree- Fock, MP2, and MP4, and also by B3LYP and B3LYP + disp
Publikováno v:
Journal of Chemical Theory and Computation. 12:2774-2778
The carbon-carbon single bond is of central importance in organic chemistry. When the molecular mechanics MM4 force field was developed beginning in the early 1990s, C-C bond lengths were not known very reliably for many important molecules, and bond
Autor:
Jiande Gu, Henry F. Schaefer, Qun Chen, Yaoming Xie, Norman L. Allinger, Xuejun Feng, Jenn-Huei Lii
Publikováno v:
Journal of chemical theory and computation. 10(4)
Catenanes are playing an increasingly important role in supramolecular chemistry. In attempting to identify the minimum number of carbon atoms in a viable catenane, the B3LYP, BP86, M06-2X, MM3, and MM4 methods were applied to study representative [2
Autor:
Norman L. Allinger
Publikováno v:
Journal of Computer-Aided Molecular Design. 25:295-316
Molecular mechanics gives us a well known model of molecular structure. It is less widely recognized that valence bond theory gives us structures which offer a direct interpretation of molecular mechanics formulations and parameters. The electronic e
Publikováno v:
Tetrahedron. 64:575-581
Enantioselective preference in the asymmetric synthesis where cyclohexene oxide is transformed enantioselectively to chiral (S)- or (R)-2-cyclohexen-1-ol by the reaction with the appropriate chiral lithium amide reagent has been evaluated theoretical
Publikováno v:
Journal of Computational Chemistry. 28:2391-2412
The MM4 force field has been extended to include aliphatic amines. About 20 amines have been examined to obtain a set of useful molecular mechanics parameters for this class. The vibrational spectra of seven amines (172 frequencies) calculated by MM4
Publikováno v:
The Journal of Organic Chemistry. 71:6512-6515
Cycloundecane (1) was shown to exist at -183.1 degrees C as a mixture of the [12323] (approximately 59%) and [335] (approximately 41%) conformations. Populations were determined from the (13)C NMR spectrum, and assignments were based on the (13)C spe
Autor:
Jenn-Huei Lii, Henry F. Schaefer, Kuo-Hsiang Chen, Norman L. Allinger, Yaoming Xie, Gerald A. Walker
Publikováno v:
The Journal of Physical Chemistry A. 110:7202-7227
A molecular mechanics study of small saturated hydrocarbons (up to C-6) substituted by up to six fluorines has been carried out with the MM4 force field. A parameter set has been developed for use in the calculation of bond lengths, bond angles, tors
Autor:
Norman L. Allinger, Yoshitaka Yamaguchi, Kazuhisa Sakakibara, Kuo-Hsiang Chen, Masatoshi Asami, Jenn-Huei Lii, Keisuke Naka
Publikováno v:
The Journal of Physical Chemistry A. 108:3048-3055
Conformational analyses in the gas phase and the prediction of the crystal structures of 5-carboxy[3.3]orthoparacyclophane (1) and 6-bromo[4.4]orthoparacyclophane (2) were carried out by using the ...
Publikováno v:
The Journal of Physical Chemistry A. 108:3006-3015
The Bohlmann effect, in its original context, occurred when, on a carbon attached to an amine nitrogen, there was a C-H bond anti-coplanar to the nitrogen lone pair. A negative hyperconjugation between the lone pair and that C-H bond (a transfer of e