Gaussian analysis of Raman spectroscopy of acetic acid reveals a significant amount of monomers that effectively cooperate with hydrogen bonded linear chains

2014 ◽  
Vol 16 (41) ◽  
pp. 22458-22461 ◽  
Author(s):  
Jianping Wu
Keyword(s):  
Raman Spectroscopy ◽  
Hydrogen Bonding ◽  
Acetic Acid ◽  
Polymer Chains ◽  
Linear Chains ◽  
Gaussian Analysis ◽  
Hydrogen Bonded

Gaussian analysis of Raman spectroscopy reveals three hydrogen bonding structures in the liquid acetic acid (AA): linear chains, cyclic dimers and dissociated monomers that effectively cooperate with hydrogen bonded stacks of linear AA or polymer chains.

Infrared Spectra of Crystalline Acetic Acid, a Hydrogen-Bonded Polymer

1977 ◽  
Vol 31 (2) ◽  
pp. 110-115 ◽  
Author(s):  
P. F. Krause ◽  
J. E. Katon ◽  
J. M. Rogers ◽  
D. B. Phillips
Keyword(s):  
Hydrogen Bonding ◽  
Acetic Acid ◽  
Infrared Spectra ◽  
Group Analysis ◽  
Structural Models ◽  
Factor Group ◽  
Vibrational Modes ◽  
Cryogenic Temperatures ◽  
Polymeric Chains ◽  
Hydrogen Bonded

The polarized infrared spectra of crystalline acetic acid and two of its deuterated derivatives, CH3COOD and CD3COOD, have been recorded from 400 to 4000 cm−1 at cryogenic temperatures. The spectroscopic results have been interpreted on the basis of a factor group analysis based on two structural models: a crystallographic cell composed of four interacting monomer units some of whose vibrational modes are highly perturbed by hydrogen bonding and a unit cell composed of two noninteracting acetic acid chains. The results are discussed in terms of possible interactions between the hydrogen-bonded acetic acid polymeric chains.

Direct observation of the cyclic dimer in liquid acetic acid by probing the CO vibration with ultrafast coherent Raman spectroscopy

2014 ◽  
Vol 16 (33) ◽  
pp. 18010-18016 ◽  
Author(s):  
Matthias Lütgens ◽  
Frank Friedriszik ◽  
Stefan Lochbrunner
Keyword(s):  
Raman Spectroscopy ◽  
Acetic Acid ◽  
Direct Observation ◽  
Cyclic Dimer ◽  
Vibrational Bands ◽  
Coherent Raman ◽  
Hydrogen Bonded

The coalescing CO vibrational bands of liquid acetic acid, caused by a mixture of hydrogen bonded aggregates, are decomposed via time and frequency resolved CARS in the specific structural contributions.

scholarly journals Two-dimensional hydrogen-bonded polymers in the crystal structures of the ammonium salts of phenoxyacetic acid, (4-fluorophenoxy)acetic acid and (4-chloro-2-methylphenoxy)acetic acid

2014 ◽  
Vol 70 (12) ◽  
pp. 528-532 ◽  
Author(s):  
Graham Smith
Keyword(s):  
Hydrogen Bonding ◽  
Acetic Acid ◽  
Water Molecule ◽  
Rotation Axis ◽  
Ammonium Salts ◽  
Phenoxyacetic Acid ◽  
Two Dimensional ◽  
The Core ◽  
Ammonium N ◽  
Hydrogen Bonded

The structures of the ammonium salts of phenoxyacetic acid, NH4+·C8H6O3−, (I), (4-fluorophenoxy)acetic acid, NH4+·C8H5FO3−, (II), and the herbicidally active (4-chloro-2-methylphenoxy)acetic acid (MCPA), NH4+·C9H8ClO3−·0.5H2O, (III) have been determined. All have two-dimensional layered structures based on inter-species ammonium N—H...O hydrogen-bonding associations, which give core substructures consisting primarily of conjoined cyclic motifs. The crystals of (I) and (II) are isomorphous with the core comprisingR12(5),R12(4) and centrosymmetricR42(8) ring motifs, giving two-dimensional layers lying parallel to (100). In (III), the water molecule of solvation lies on a crystallographic twofold rotation axis and bridges two carboxyl O atoms in anR44(12) hydrogen-bonded motif, creating twoR43(10) rings, which together with a conjoined centrosymmetricR42(8) ring incorporating both ammonium cations, generate two-dimensional layers lying parallel to (100). No π–π ring associations are present in any of the structures.

scholarly journals Raman Spectroscopy for the Competition of Hydrogen Bonds in Ternary (H2O–THF–DMSO) Aqueous Solutions

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3666
Author(s):  
Liu ◽  
Zhang ◽  
Huang ◽  
Wu ◽  
Ouyang
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bond ◽  
Raman Spectroscopy ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Aqueous Solutions ◽  
Dimethyl Sulfoxide ◽  
Water Molecules ◽  
Bonding Theory ◽  
Hydrogen Bonded

The effects of hydrogen bonds on the molecular structure of water-tetrahydrofuran (H2O–THF), water-dimethyl sulfoxide (H2O–DMSO), and water-tetrahydrofuran-dimethyl sulfoxide (H2O–THF–DMSO) in binary aqueous solutions and ternary aqueous solutions were studied using Raman spectroscopy. The results indicate that in the binary aqueous solution, the addition of THF and DMSO will generate hydrogen bonds with water molecules, resulting in changes in the peak positions of S=O bonds and C–O bonds. Compared with the binary aqueous solutions, the hydrogen bonds between DMSO and THF, and the hydrogen bonds between DMSO and H2O in the ternary aqueous solutions are competitive, and the hydrogen bond competition is susceptible to water content. In addition, the formation of hydrogen bonds will destroy the fully hydrogen-bonded water and make it change to the partially hydrogen-bonded water. By fitting the spectra into the three Gaussian components assigned to water molecules with different hydrogen bonding (HB) environments, these spectral features are interpreted by a mechanism that H2O in different solution systems has equal types of water molecules with similar HB degrees-fully hydrogen-bonded H2O (FHW) and partially hydrogen-bonded H2O (PHW). The ratio of the intensity transition from FHW to PHW is determined based on Gaussian fitting. Therefore, the variation of hydrogen bond competition can be supplemented by the intensity ratio of PHW/FHW ((IC2 + IC3)/IC1). This study provides an experimental basis for enriching the hydrogen bonding theory of multivariate aqueous solution systems.

Electrogeneration of Conducting Poly(α-tetrathiophene). Effect of Solution Stirring and Detection of Linear Oligomers

2003 ◽  
Vol 68 (7) ◽  
pp. 1326-1344 ◽  
Author(s):  
Francesc Estrany ◽  
Ramon Oliver ◽  
Esther García ◽  
Esther Gualba ◽  
Pere-Lluís Cabot ◽  
...  
Keyword(s):  
Ion Pairs ◽  
Polymer Chains ◽  
Polymerization Process ◽  
Anodic Process ◽  
Cathodic Peak ◽  
Linear Chains ◽  
Monomer Solution ◽  
Ir Analysis ◽  
Microscopy Images ◽  
Tof Ms

The anodic oxidation of α-tetrathiophene on Pt was studied in a 1.0 mM monomer solution in 0.1 M LiClO4 in 45:35:20 acetonitrile/ethanol/DMF. Three consecutive oxidation peaks were detected by cyclic voltammetry, along with a cathodic peak related to the reduction of electroactive polarons formed during the first anodic process. Uniform, adherent, insoluble and black polymer films were obtained by chronoamperometry at 1.000 V vs Ag|AgCl corresponding to the first oxidation-polymerization process. Stirring of monomer solution promotes the production of polymer, favoring the oxidation of polymer chains with the incorporation of more doping ClO4- ions and ion pairs of Li+ClO4- in their monomeric units. The conductivity of the polymer obtained under stirring was three orders of magnitude higher than that synthesized from a quiescent solution. The scanning electron microscopy images also showed much more uniform films under stirring. This behavior points to the existence of less crosslinking in the polymer and the production of longer linear chains when the solution is stirred. IR analysis of these materials confirmed the formation of crosslinked chains with predominance of β-β linkages. Short linear oligomers such as the dimer, trimer and tetramer were detected in all polymers by MALDI-TOF-MS, thus showing a radical polycondensation as initial electropolymerization mechanism. A larger proportion of linear oligomers is formed under solution stirring.

Tuning of Electronic Properties in Conducting Polymers

2001 ◽  
Vol 66 (8) ◽  
pp. 1208-1218 ◽  
Author(s):  
Guofeng Li ◽  
Mira Josowicz ◽  
Jiří Janata
Keyword(s):  
Hydrogen Bonding ◽  
Binding Site ◽  
Binding Sites ◽  
Polymer Chains ◽  
Electronic Transitions ◽  
Weakly Bound ◽  
Ordered Structures ◽  
Doped Polymer ◽  
Positively Charged ◽  
Repeated Cycling

Structural and electronic transitions in poly(thiophenyleneiminophenylene), usually referred to as poly(phenylenesulfidephenyleneamine) (PPSA) upon electrochemical doping with LiClO4 have been investigated. The unusual electrochemical behavior of PPSA indicates that the dopant anions are bound in two energetically different sites. In the so-called "binding site", the ClO4- anion is Coulombically attracted to the positively charged S or N sites on one chain and simultaneously hydrogen-bonded with the N-H group on a neighboring polymer chain. This strong interaction causes a re-organization of the polymer chains, resulting in the formation of a networked structure linked together by these ClO4- Coulombic/hydrogen bonding "bridges". However, in the "non-binding site", the ClO4- anion is very weakly bound, involves only the electrostatic interaction and can be reversibly exchanged when the doped polymer is reduced. In the repeated cycling, the continuous and alternating influx and expulsion of ClO4- ions serves as a self-organizing process for such networked structures, giving rise to a diminishing number of available "non-binding" sites. The occurrence of these ordered structures has a major impact on the electrochemical activity and the morphology of the doped polymer. Also due to stabilization of the dopant ions, the doped polymer can be kept in a stable and desirable oxidation state, thus both work function and conductivity of the polymer can be electrochemically controlled.

Theoretical study of hydrogen bonding interactions in substituted nitroxide radicals

2021 ◽  
Author(s):  
Thufail M. Ismail ◽  
Neetha Mohan ◽  
P. K. Sajith
Keyword(s):  
Hydrogen Bonding ◽  
Interaction Energy ◽  
Electrostatic Potential ◽  
Molecular Electrostatic Potential ◽  
Theoretical Study ◽  
Nitroxide Radicals ◽  
Hydrogen Bonding Interactions ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Interaction energy (Eint) of hydrogen bonded complexes of nitroxide radicals can be assessed in terms of the deepest minimum of molecular electrostatic potential (Vmin).

Understanding water structure from Raman spectra of isotopic substitution H2O/D2O up to 573 K

2017 ◽  
Vol 19 (32) ◽  
pp. 21540-21547 ◽  
Author(s):  
Qingcheng Hu ◽  
Haiwen Zhao ◽  
Shunli Ouyang
Keyword(s):  
Hydrogen Bonding ◽  
Raman Spectra ◽  
Water Structure ◽  
Free Water ◽  
Isotopic Substitution ◽  
Structure Model ◽  
Single Donor ◽  
Hydrogen Bonded

The OH/OD stretch band features on Raman spectra of isotopic substitution H2O/D2O at temperatures up to 573 K are correlated with a multi-structure model that water has five dominant hydrogen bonding configurations: tetrahedral, deformed tetrahedral, single donor, single hydrogen bonded water and free water.

Concomitant polymorphs of 1,3-bis(3-fluorophenyl)urea

2016 ◽  
Vol 72 (9) ◽  
pp. 692-696 ◽  
Author(s):  
Christina A. Capacci-Daniel ◽  
Jeffery A. Bertke ◽  
Shoaleh Dehghan ◽  
Rupa Hiremath-Darji ◽  
Jennifer A. Swift
Keyword(s):  
Hydrogen Bonding ◽  
Crystal Engineering ◽  
Structural Motif ◽  
Parallel Orientation ◽  
One Dimensional ◽  
Monoclinic Form ◽  
Engineering Studies ◽  
Hydrogen Bonded

Hydrogen bonding between urea functionalities is a common structural motif employed in crystal-engineering studies. Crystallization of 1,3-bis(3-fluorophenyl)urea, C13H10F2N2O, from many solvents yielded concomitant mixtures of at least two polymorphs. In the monoclinic form, one-dimensional chains of hydrogen-bonded urea molecules align in an antiparallel orientation, as is typical of many diphenylureas. In the orthorhombic form, one-dimensional chains of hydrogen-bonded urea molecules have a parallel orientation rarely observed in symmetrically substituted diphenylureas.

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