scholarly journals Steric Constraint in the Primary Photoproduct of an Archaeal Rhodopsin from Regiospecific Perturbation of C−D Stretching Vibration of the Retinyl Chromophore

2005 ◽  
Vol 127 (46) ◽  
pp. 16036-16037 ◽  
Author(s):  
Yuki Sudo ◽  
Yuji Furutani ◽  
Akimori Wada ◽  
Masayoshi Ito ◽  
Naoki Kamo ◽  
...  
Keyword(s):  
Stretching Vibration ◽  
Steric Constraint

Infrared spectra and substituent effects in 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones

1983 ◽  
Vol 48 (2) ◽  
pp. 586-595 ◽  
Author(s):  
Alexander Perjéssy ◽  
Pavol Hrnčiar ◽  
Ján Šraga
Keyword(s):  
Substituent Effects ◽  
Phenyl Group ◽  
Wave Number ◽  
Vibrational Coupling ◽  
Wave Numbers ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
The Relationship ◽  
Derivatives Of ◽  
Effect Of Structure

The wave numbers of the fundamental C=O and C=C stretching vibrations, as well as that of the first overtone of C=O stretching vibration of 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones and 1,3-cycloheptanedione were measured in tetrachloromethane and chloroform. The spectral data were correlated with σ+ constants of substituents attached to phenyl group and with wave number shifts of the C=O stretching vibration of substituted acetophenones. The slope of the linear dependence ν vs ν+ of the C=C stretching vibration of the ethylenic group was found to be more than two times higher than that of the analogous correlation of the C=O stretching vibration. Positive values of anharmonicity for asymmetric C=O stretching vibration can be considered as an evidence of the vibrational coupling in a cyclic 1,3-dicarbonyl system similarly, as with derivatives of 1,3-indanedione. The relationship between the wave numbers of the symmetric and asymmetric C=O stretching vibrations indicates that the effect of structure upon both vibrations is symmetric. The vibrational coupling in 1,3-cycloheptanediones and the application of Seth-Paul-Van-Duyse equation is discussed in relation to analogous results obtained for other cyclic 1,3-dicarbonyl compounds.

Darstellung, 11B-, 13C-, 29Si-NMR- und Schwingungsspektren von Trimethylsilylmethyl-hexahydro-closo-hexaborat, [B6H6(CH2Si(CH3)3)]- sowie Kristallstruktur von [P(C6H5)4][B6H6(CH2Si(CH3)3)] / Preparation, 11B, 13C, 29Si NMR and Vibrational Spectra of Trimethylsilylmethyl-hexahydro-clo-hexaborate, [B6H6(CH2Si(CH 3)3)]-and the Crystal Structure of [P(C6H5)4] [B6H6(CH2Si(CH3)3)]

1995 ◽  
Vol 50 (7) ◽  
pp. 1025-1029 ◽  
Author(s):  
J. Baurmeister ◽  
A. Franken ◽  
W. Preetz
Keyword(s):  
Crystal Structure ◽  
Monoclinic Space Group ◽  
29Si Nmr ◽  
X Ray Diffraction ◽  
Nmr Spectrum ◽  
X Ray ◽  
Quadrupole Coupling ◽  
Stretching Vibration ◽  
Ir And Raman ◽  
C Nmr

By reaction of [N(C4H9 )4]2 [B6H6] with iodomethyl-trimethylsilane in acetonitrile a solution with trimethylsilylm ethyl-closo-hexaborate(1-)anions, [B6H6 (CH2Si(CH3)3)]-, is formed. The crystal structure of [P(C6H5 )4][B6H6(CH2Si(CH3)3)] has been determined by single crystal X-ray diffraction analysis; monoclinic, space group P21/n with a = 16.140(2), b = 11.646(8), c = 16.731(3) Å, β 109.664(11)°. The 11B NMR spectrum reveals features of a mono hetero substituted octahedral B6 cage. The 13C NMR spectrum exhibits a quartet at +0.18 ppm with 1J(C,H) = 118 Hz for the three methyl groups and a weak multiplet at -0.65 ppm for the methylene bridge due to quadrupole coupling with the boron atoms. In the 29Si NMR spectrum a decet at +2.25 ppm with 2J(C,H ) = 6.9 Hz is observed. The B -C stretching vibration is observed at 1155 cm-1 in the IR and Raman spectrum.

scholarly journals Iron-histidine stretching vibration in the deoxy state of insect hemoglobins with different O2 affinities and Bohr effects.

1985 ◽  
Vol 260 (23) ◽  
pp. 12665-12669
Author(s):  
E A Kerr ◽  
N T Yu ◽  
K Gersonde ◽  
D W Parish ◽  
K M Smith
Keyword(s):  
Stretching Vibration

POSSIBILITY OF MOLECULAR-SWITCH WITH CONTROLLED HYDROGEN BOND: UTILITY OF COMBINATION OF 2,2′-BIIMIDAZOLE AND REDOX-ACTIVE LIGAND

2005 ◽  
Vol 04 (01) ◽  
pp. 333-344 ◽  
Author(s):  
HIROTOSHI MORI ◽  
EISAKU MIYOSHI
Keyword(s):  
Density Functional ◽  
Molecular Level ◽  
Molecular Switch ◽  
Vibration Band ◽  
Functional Theory ◽  
Inorganic Molecule ◽  
Redox Active Ligand ◽  
Active Ligand ◽  
Redox Active ◽  
Stretching Vibration

A new inorganic molecule [ Co(Hbim) ( C 6 H 4 O 2)( NH 3)2]2 that can be used as a new optically durable molecular switch was theoretically designed in the framework of density functional theory. Three stable minima, belonging to 1 A g , 5 A 1, and 9 A g states, were found in the complex. Theoretically predicted infrared spectra of the complexes showed that a strong peak of NH stretching vibration is observed at 2690, 2120, and 2770 cm -1 in the 1 A g , 5 A 1, and 9 A g states, respectively. The apparent red shift of the NH stretching vibration band in the 5 A 1 state make it possible to distinguish the electronic state from others (1 A g and 9 A g ). This means that the complex can be used as a molecular level switch whose memory can be stably read by IR light without any photoreaction process; namely, without memory degradation.

Effects of steric constraint on chromium(III) complexes of tetraazamacrocycles, 4: Comparison of the trans-difluoro-complexes of tet a, 1,4-C2-cyclam, and 1,11-C3-cyclam

2007 ◽  
Vol 360 (5) ◽  
pp. 1482-1492 ◽  
Author(s):  
Michael T. Vagnini ◽  
W. Caleb Rutledge ◽  
Chuanjiang Hu ◽  
Donald G. VanDerveer ◽  
Paul S. Wagenknecht
Keyword(s):  
Steric Constraint

The resonance Raman spectra and excitation profiles of some 4-sulfamylazobenzenes

1977 ◽  
Vol 55 (9) ◽  
pp. 1444-1453 ◽  
Author(s):  
Kamal Kumar ◽  
P. R. Carey
Keyword(s):  
Raman Spectrum ◽  
Raman Spectra ◽  
Resonance Raman ◽  
Valence Bond ◽  
Wavelength Dependence ◽  
Accurate Estimation ◽  
Intensity Changes ◽  
Stretching Vibration ◽  
Resonance Raman Spectra ◽  
Frequency Changes

The resonance Raman spectra of three pharmacologically important sulfonamides, 4-sulfamyl-4′-dimethylaminoazobenzene (1), 4-sulfamyl-4′-hydroxyazobenzene (2), and 4-sulfamyl-4′-aminoazobenzene (3), are compared with those of analogues lacking the sulfonamide group. The —SO2NH2 moiety does not directly contribute intense or moderately intense bands to the resonance Raman spectra of 1, 2, and 3. However, —SO2NH2 ionization is reflected by frequency changes in a band near 1140 cm−1 and intensity changes in the 1420 cm−1 region. The normal Raman spectrum of 2 confirms that the intensity changes reflect —SO2NH2 ionization rather than unrelated changes in vibronic coupling. The effect of —OH ionization on the resonance Raman spectrum of 2 emphasizes that caution must be exercised when relating spectral perturbations to changes in contributions from valence bond type structures. Resonance Raman excitation profiles for the 1138, 1387, and 1416 cm−1 bands of 2 show that these bands gain intensity by coupling with the electronic transitions in the 240 to 450 nm region and that, more than 1000 cm−1 to the red of λmax, the wavelength dependence can be closely reproduced by the FB type terms of Albrecht and Hutley. The excitation profile for each band shows evidence for structure in the 470 nm region, although lack of sufficient excitation wavelengths prevents accurate estimation of the spacing. Under conditions of rigorous resonance the intense Raman lines all occur in the 1400 cm−1 region, i.e. they are 'bunched' in the region known to contain the —N=N— stretching vibration.

The effects of bending and stretching vibration on the reaction of acetylene cations with methane

1989 ◽  
Vol 90 (3) ◽  
pp. 1577-1587 ◽  
Author(s):  
Thomas M. Orlando ◽  
Baorui Yang ◽  
Scott L. Anderson
Keyword(s):  
Stretching Vibration
Sign in / Sign up

Export Citation Format

Share Document