Spectroscopic and theoretical evidence for the cooperativity between red-shift hydrogen bond and blue-shift hydrogen bond in DMSO aqueous solutions

2008 ◽  
Vol 69 (1) ◽  
pp. 211-215 ◽  
Author(s):  
Qingzhong Li ◽  
Xiulin An ◽  
Baoan Gong ◽  
Jianbo Cheng
Keyword(s):  
Hydrogen Bond ◽  
Aqueous Solutions ◽  
Blue Shift ◽  
Red Shift ◽  
Theoretical Evidence

scholarly journals A theoretical study on the red- and blue-shift hydrogen bonds of cis-trans formic acid dimer in excited states

2013 ◽  
Vol 11 (2) ◽  
pp. 171-179 ◽  
Author(s):  
Dapeng Yang ◽  
Yonggang Yang ◽  
Yufang Liu
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Formic Acid ◽  
Excited States ◽  
Density Functional ◽  
Blue Shift ◽  
Red Shift ◽  
Functional Theory ◽  
Photophysical Study ◽  
Tddft Method

AbstractThe excited states of cis-trans formic acid dimer and its monomers have been investigated by time-dependent density functional theory (TDDFT) method. The formation of intermolecular hydrogen bonds O1-H1...O2=C2 and C2-H2...O4=C1 induces bond length lengthening of the groups related to the hydrogen bond, while that of the C2-H2 group is shortened. It is demonstrated that the red-shift hydrogen bond O1-H1...O2=C2 and blue-shift hydrogen bond C2-H2...O4=C1 are both weakened when excited to the S1 state. Moreover, it is found that the groups related to the formation of red-shift hydrogen bond O1-H1...O2=C2 are both strengthened in the S1 state, while the groups related to the blue-shift hydrogen bond C2-H2...O4=C1 are both weakened. This will provide information for the photochemistry and photophysical study of red- and blue-shift hydrogen bond.

Observation of an Unusually Large IR Red-Shift in an Unconventional S–H···S Hydrogen-Bond

2021 ◽  
Vol 12 (4) ◽  
pp. 1228-1235
Author(s):  
Kamal K. Mishra ◽  
Kshetrimayum Borish ◽  
Gulzar Singh ◽  
Prakash Panwaria ◽  
Surajit Metya ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Red Shift

Theoretical analysis of the (HNO)2, (HNO···HNS), and (HNS)2 dimers — A case of red and blue shifts of N–H stretching frequency

2010 ◽  
Vol 88 (8) ◽  
pp. 849-857 ◽  
Author(s):  
Nguyen Tien Trung ◽  
Tran Thanh Hue ◽  
Minh Tho Nguyen
Keyword(s):  
Hydrogen Bond ◽  
Quantum Chemical ◽  
Bond Formation ◽  
Blue Shift ◽  
Proton Donor ◽  
Basis Sets ◽  
Coupled Cluster ◽  
Hydrogen Bond Formation ◽  
Length Contraction ◽  
Moller Plesset

The hydrogen-bonded interactions in the simple (HNZ)2 dimers, with Z = O and S, were investigated using quantum chemical calculations with the second-order Møller–Plesset perturbation (MP2), coupled-cluster with single, double (CCSD), and triple excitations (CCSD(T)) methods in conjunction with the 6-311++G(2d,2p), aug-cc-pVDZ, and aug-cc-pVTZ basis sets. Six-membered cyclic structures were found to be stable complexes for the dimers (HNO)2, (HNS)2, and (HNO–HNS). The pair (HNS)2 has the largest complexation energy (–11 kJ/mol), and (HNO)2 the smallest one (–9 kJ/mol). A bond length contraction and a frequency blue shift of the N–H bond simultaneously occur upon hydrogen bond formation of the N–H···S type, which has rarely been observed before. The stronger the intramolecular hyperconjugation and the lower the polarization of the X–H bond involved as proton donor in the hydrogen bond, the more predominant is the formation of a blue-shifting hydrogen bond.

Unusual spectral shifts in the prototropic reactions of 2,7-diaminofluorene

1987 ◽  
Vol 65 (9) ◽  
pp. 2013-2018 ◽  
Author(s):  
R. Manoharan ◽  
Sneh K. Dogra
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Medium ◽  
Fluorescence Spectrum ◽  
Blue Shift ◽  
Proton Donor ◽  
Red Shift ◽  
The Other ◽  
Spectral Shifts ◽  
Other Hand

The red shift observed in the absorption spectrum of 2,7-diaminofluorene (DAF) in ether and acetonitrile is either due to the proton-donating capacity of the solute or due to its dispersive interactions with the solvent and a blue shift in methanol and water is due to the proton-accepting nature of DAF. DAF acts as a proton donor in S1 state in all solvents. The red shift in the fluorescence spectrum of the monocation of DAF relative to that of DAF is not because of the —NH2 group becoming more basic but because of the large solvent relaxating in aqueous medium. On the other hand, the monocation of DAF in cyclohexane follows the normal blue shift in the fluorescence spectrum. pKa values for the various prototropic reactions in S0 and S1 states are determined and discussed.

scholarly journals Impact of Solvents, Magnesium Oxide and Aluminium Oxide Nanoparticles on the Photophysical Properties of Acridine Orange Dye

2021 ◽  
pp. 1-7
Author(s):  
Fairooz Kareem ◽  
Mahasin Al-Kadhemy ◽  
Asrar Saeed
Keyword(s):  
Acridine Orange ◽  
Magnesium Oxide ◽  
Fluorescence Spectra ◽  
Aluminium Oxide ◽  
Blue Shift ◽  
Red Shift ◽  
Oxide Nanoparticles ◽  
Absorption And Fluorescence Spectra ◽  
Aluminium Oxide Nanoparticles ◽  
Al2o3 Nps

Absorption and fluorescence spectroscopy techniques were applied to investigate the photophysical characteristics of acridine orange (AO) dye in solvents that included distilled water, dimethyl sulfoxide (DMSO), acetone and ethanol in various concentrations (1×10-4–1×10-6) M. All of the samples were served at room temperature. The relationships between various parameters describing the strength of optical transitions in atoms and molecules were reviewed. This study expresses various viewpoints by describing how concentration and solvent affect the dye's absorption and fluorescence spectra. The absorption spectra of AO exhibit a band at (490 nm), except for DMSO, which shifts more towards red by 5 nm. The fluorescence spectra show a blue shift in AO aqueous solution around 6 nm until (0.5×10-4) M, followed by a red shift at around 7 nm at (1×10-6) M. There is a blue shift in (1×10-5) M for DMSO at around 4 nm, then a 10 nm red shift in higher concentrations as well as a 9 nm red shift in acetone and 6 nm in ethanol. Adding magnesium oxide nanoparticles (MgO NPs) quenched AO in both absorption and fluorescence spectra, whereas maximum fluorescence and intensity increased when aluminium oxide nanoparticles (Al2O3 NPs) were added to the solution. KEYWORDS Laser dye, absorption spectrum, fluorescence spectrum, MgO NPs, Al2O3 NPs

X-ray Absorption Spectroscopy Study of the Hydrogen Bond Network in the Bulk Water of Aqueous Solutions

2005 ◽  
Vol 109 (27) ◽  
pp. 5995-6002 ◽  
Author(s):  
Lars-Åke Näslund ◽  
David C. Edwards ◽  
Philippe Wernet ◽  
Uwe Bergmann ◽  
Hirohito Ogasawara ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Aqueous Solutions ◽  
Absorption Spectroscopy ◽  
Bulk Water ◽  
Hydrogen Bond Network ◽  
Spectroscopy Study ◽  
X Ray ◽  
Bond Network ◽  
X Ray Absorption

scholarly journals Interaction Mechanism between Antibiotics and Humic Acid by UV-Vis Spectrometry

2018 ◽  
Vol 15 (9) ◽  
pp. 1911 ◽  
Author(s):  
Xiaoyu Yuan ◽  
Shengke Yang ◽  
Jie Fang ◽  
Xueli Wang ◽  
Haizhen Ma ◽  
...  
Keyword(s):  
Humic Acid ◽  
Absorption Band ◽  
Interaction Mechanism ◽  
Blue Shift ◽  
Degree Of Polymerization ◽  
Ultraviolet Spectrum ◽  
Red Shift ◽  
Vis Spectroscopy ◽  
Nm Range ◽  
Peak Value

In this study, the interaction between the humus and two antibiotics was studied by UV-Vis spectroscopy to describe the interaction mechanism and the effects of different environmental factors on the mechanism. Results showed that humic acid (HA) containing more aromatic groups was easily associated with antibiotics. In the HA-OTC, with the increase of the concentration of OTC, there were obvious absorption peaks in the 230–260 nm and 330–360 nm range, and the absorption band of the HA ultraviolet spectrum underwent a slight blue shift and the absorption intensity increased, demonstrating that a new ground state complex was generated. In the HA-SD, with the increase of SD concentration, an aromatic structure absorption peak appeared in the 190–220 nm range, and the peak value increased and the absorption band underwent a red shift, and the aromatization of HA decreased, which enhanced the interaction between the antibiotics and HA. With the increase of pH, the absorption band of HA, HA-OTC and HA-SD ultraviolet spectrum suffered a blue shift, the degree of polymerization of HA molecules decreased, and the number of adsorption binding sites increased, which resulted in the interaction of HA with antibiotics being enhanced. The absorption band of HA, HA-OTC and HA-SD displayed a red shift with the increase of ionic strength, which indicated that the repulsion within HA particles was weakened, and the molecular polymerization was strengthened and therefore, the interaction between antibiotics and HA was inhibited. The UV characteristics of the HA, HA-OTC and HA-SD systems were insensitive to the temperature. This study lays the foundation for better studying the effect of humus on the distribution of antibiotic residues in the environment.

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