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Experimental information on the CX⋯π halogen bonding motif was obtained by studying the formation of molecular complexes of CF 3 Cl, CF 3 Br and CF 3 I with ethyne, propyne and 2-butyne in liquid krypton, using FTIR and Raman spectroscopy. For CF 3 Br, experimental evidence was found for the formation of 1:1 complexes with propyne and 2-butyne only, while for CF ...
FTIR spectra of the gas phase Cl 3 CD+TMA mixture have been studied at room temperature in ∼800–4000cm −1 frequency domain. The formation of the H-bonded Cl 3 CD…TMA complex has been detected. Spectroscopic parameters of the band ascribed to the complex were evaluated. MP2 frozen core ab initio calculations have been carried out with the Pople-type 6-311++G(d,p) basis set....
The reactions of Co(II) sources with N-salicylidene-o-aminophenol (H 2 saph), N-salicylidene-o-amino-4-methylphenol (H 2 saph-4Me) and N-salicylidene-o-amino-4-chlorophenol (H 2 saph-4Cl) were studied in MeOH. The new solid complexes (Bu4nN)[Co III (saph) 2 ] (1), (Et 3 NH)[Co III (saph-4Me) 2 ]⋅MeOH⋅MeCO 2 H (2⋅MeOH⋅MeCO ...
Infrared (IR) and vibrational circular dichroism (VCD) spectra of N-Acetyl-l-Cysteine Methyl Ester (NALCME) and N-Acetyl-l-Cysteine (NALC) in D 2 O under different pHs were measured. We focus on the VCD signatures of the amide I and the CO stretching spectral signatures of the neutral NALCME and NALC species and the related ones of the deprotonated NALC species in the region of 1800–1500cm...
An infrared spectroscopic and MP2/6–311++G(2d,2p) study of hydrogen bonded complexes of formaldoxime with ammonia and hydrogen chloride trapped in solid argon matrices is reported. Both 1:1 and 1:2 complexes between formaldoxime and ammonia, hydrogen chloride have been identified in the CH 2 NOH/NH 3 /Ar, CH 2 NOH/HCl/Ar matrices, respectively, their structures were determined...
The infrared and Raman spectra of vapor-phase and liquid-phase benzocyclobutane (BCB) have been recorded and assigned. The structure of the molecule was calculated using the MP2/cc-pVTZ basis set and the vibrational frequencies and spectral intensities were calculated using the B3LYP/cc-pVTZ level of theory. The agreement between experimental and calculated spectra is excellent. In order to allow...
The electronegativity equalization method is classically used as a method allowing the fast generation of atomic charges using a set of calibrated parameters and provided knowledge of the molecular structure. Recently, it has started being used for the calculation of other reactivity descriptors and for the development of polarizable and reactive force fields. For such applications, it is of interest...
The infrared and Raman spectra (3200–50cm −1 ) of the gas, liquid or solution, and solid have been recorded of isocyanocyclopentane, c-C 5 H 9 NC. FT-microwave studies have also been carried out and 23 transitions were recorded for the envelope-axial (Ax) conformer. Variable temperature (−65 to −100°C) studies of the infrared spectra (3200–400cm −1 ) dissolved in liquid...
The dimers with general formula FH/FLi⋯HCCX and HCCX⋯OH 2 , and the trimers FH⋯HCCX⋯OH 2 (X=F, Cl, Br, H), were optimized computationally to stable structures. These model systems derive their strength from a combination of H⋯π (or Li⋯π) electrostatic interactions in the T-shaped FH/FLi⋯HCCX dimers and halogen bonding between the X and the O atom of H 2 O (or CH⋯O hydrogen-bonding...
The rotational spectrum of the CH 2 F 2 ...H 217 O adduct has been measured in the 6.5-18.5GHz range using a pulsed jet Fourier-transform microwave spectrometer. The experimental values of the 17 O quadrupole coupling constants have been determined to be χ aa =-3.853(6), χ bb =-3.259(1) and χ cc =7.112(9) MHz, respectively...
Monomers of trans- (TS) and cis-stilbene (CS) were isolated in cryogenic argon and xenon matrices, and their infrared (IR) spectra were fully assigned and interpreted. The interpretation of the vibrational spectra received support from theoretical calculations undertaken at the DFT(B3LYP)/6-311++G(d,p) level of theory. In situ broadband UV irradiation of the matrix-isolated CS led to its isomerization...
The tautomeric equilibria for 2-pyridoyl-, 3-pyridoyl-, and 4-pyridoyl-benzoyl methane have been investigated using deuterium isotope effects on 1 H and 13 C chemical shifts both in the liquid and the solid state. Equilibria are established both in the liquid and the solid state. In addition, in the solution state the 2-bond and 3-bond J( 1 H– 13 C) coupling constants...
Variable temperature (−60 to −100°C) studies of ethyldichlorophosphine, CH 3 CH 2 PCl 2 , of the infrared spectra (4000–400cm −1 ) dissolved in liquid xenon have been carried out. From these data, the two conformers have been identified and the enthalpy difference has been determined between the more stable trans conformer and the less stable gauche form to be 88±9cm...
As intermolecular interactions such as the hydrogen bond are electrostatic in origin, rigorous treatment of this term within force field methodologies should be mandatory. We present a method able of accurately reproducing such interactions for seven van der Waals complexes. It uses atomic multipole moments up to hexadecupole moment mapped to the positions of the nuclear coordinates by the machine...
The 1:1 hydrogen bonded complexes between glyoxylic acid (GA) and water are studied in low temperature argon matrices. Four different complex structures were found in deposited matrices. The lowest energy conformer (T1) of GA was found to form complex, where the water molecule was attached to the opposite side of the intramolecular hydrogen bond in the molecule (T1B). Interestingly, this complex was...
Raman spectra of 1,1-difluoro-1-silacyclohexane as a liquid, and as a solid at 78K were recorded and depolarization data obtained. The infrared spectra of the vapour, liquid and amorphous and crystalline solids have been studied. In the low temperature IR and Raman spectra eight and three bands, respectively, were shifted a few cm −1 when the sample crystallized. No bands vanished after crystallization...
Weak molecular interactions of 1,2-dichloroethane dissolved in paraffin oil were investigated by FTIR spectroscopy. Occurrence of isosbestic points in the spectra along with the factor analysis showed that DCE⋯DCE dimers are formed in solutions at DCE concentrations between 7 and 15vol.%. It was found that both trans and gauche conformers are involved in the complexation, forming a tg-dimer. From...
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