Synthesis and Evaluation of FICA Derivatives as Chiral Derivatizing Agents.

1-Fluoroindan-1-carboxyic acid (FICA) derivatives containing a monosubstituted benzene ring (1b-e) were synthesized as their methyl esters and their potential as chiral derivatizing agents (CDAs) were assessed by both F- and H-NMR spectroscopy. Introduction of a substituent at the 4-position in the benzene ring caused a 1.2-2 fold increase in Δδ values when compared with that of FICA.

H/D isotope effect in methyl torsional interaction of acetone as calculated by a multicomponent molecular orbital method.

We analyzed the H/D isotope effect in the methyl torsional interactions accompanying two methyl internal rotations for acetone (CH(3)COCH(3)) and deuterated acetone (CD(3)COCD(3) and CH(3)COCD(3)) in the ground state by means of the multicomponent molecular orbital (MC_MO) method, which directly accounts for the quantum effects of protons and deuterons. Our estimated rotational constants and moments of inertia for CH(3)COCH(3) and CD(3)COCD(3) agreed well with the experimental results because of the adequate treatment of protonic and deuteronic quantum effects afforded by the MC_MO method. Because the C-D bond distance in the CD(3) group was shorter than the C-H distance in CH(3) owing to the anharmonicity of the potential, the difference in potential energy surfaces of CH(3)COCH(3), CD(3)COCD(3), and CH(3)COCD(3) was strongly related to the differences induced in geometrical parameters by the H/D isotope effect.

HD isotope effect of methyl internal rotation for acetaldehyde in ground state as calculated from a multicomponent molecular orbital method.

We have analyzed the differences in the methyl internal rotation induced by the HD isotope effect for acetaldehyde (CH(3)CHO) and deuterated acetaldehyde (CD(3)CDO) in ground state by means of the multicomponent molecular orbital (MC_MO) method, which directly accounts for the quantum effects of protons and deuterons. The rotational constant of CH(3)CHO was in reasonable agreement with experimental one due to the adequate treatment of the protonic quantum effect by the MC_MO method. The C-D bond distances were about 0.

Case of cheilitis granulomatosa associated with apical periodontitis.

The etiology of cheilitis granulomatosa is unknown. In some cases, rapid improvement and/or complete elimination of swelling of the lips after dental treatment has been reported. Here, we describe another case of improvement following dental treatment.

Monozygotic twins with congenital guttate leukoderma.

We report here two cases of congenital guttate hypomelanotic macules observed in monozygotic twins. They both have had discrete leukoderma regions in the axillae, inguinal region and lower abdomen since birth. The size and the shape did not change until at least the age of nine.

Theoretical study of intramolecular interaction energies during dynamics simulations of oligopeptides by the fragment molecular orbital-Hamiltonian algorithm method.

We analyzed the interaction energies between residues (fragments) in an oligopeptide occurring during dynamic simulations by using the fragment molecular orbital-Hamiltonian algorithm (FMO-HA) method, an ab initio MO-molecular dynamics technique. The FMO method enables not only calculation of large molecules based on ab initio MO but also easy evaluation of interfragment interaction energies. The glycine pentamer [(Gly)(5)] and decamer [(Gly)(10)] were divided into five and ten fragments, respectively.

Conformers of Saturated Chains: Matrix Isolation, Structure, IR and UV Spectra of n-Si Me.

Infrared and ultraviolet spectra of the gauche and anti conformers of matrix-isolated permethyl-n-tetrasilane have been obtained separately by taking advantage of thermally induced gauche-to-anti conversion and of wavelength-selective photochemical destruction of either conformer. The resolved UV spectrum of the gauche conformer provides the first piece of experimental evidence in favor of the recently proposed reinterpretation of conformational effects on tetrasilane electronic states. According to this, it is not the energy but the intensity of the lowest singlet excitation that changes dramatically as the SiSiSiSi dihedral angle is varied, as a result of an avoided crossing between s̀s̀* and s̀π* states.