IR Study of ion-molecular interactions in a DMF-HCl system

Maiorov, V. D.; Sysoeva, S. G.; Темкин, О. Н.; Kislina, L. S.

doi:10.1007/bf00699185

Cited by 17 publications

(7 citation statements)

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“…Such species are most likely uncharged complexes of HCl with one alcohol molecule, namely, Et(H)O···H + ···Cl − . Formation of similar uncharged complexes was observed in solutions of HCl in N , N ‐dimethylformamide (Me 2 NC(H)O) by means of vibrational spectroscopy and quantum chemical calculations . The structure of the neutral Me 2 NC(H)O···H + ···Cl − complex was established by X‐ray study of the cocrystals of HCl with N , N ‐dimethylformamide .…”

Section: Resultsmentioning

confidence: 82%

“…With an excess of solvent, OH terminal groups of these species form H‐bonds with the solvent molecules (Scheme ). Partial solvation of these species leads to a decrease in the CA coefficient . On the other hand, solvation slightly affects vibrational frequencies of the (quasi)symmetrical O···H + ···O unit, because they are highly characteristic …”

Section: Resultsmentioning

confidence: 99%

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The structure and vibrational features of proton disolvates in water-ethanol solutions of HCl: the combined spectroscopic and theoretical study

Maiorov

Кислина

Rykounov

et al. 2013

J. Phys. Org. Chem.

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The infrared (IR) spectra of water–ethanol (EtOH) solutions of HCl are measured over a wide range of acid concentration at fixed H2O―EtOH ratios (1 : 1, 1 : 2, and 1 : 40). In these systems, different proton disolvates with (quasi)symmetrical H‐bonds are formed. Their structure and vibrational features are revealed by the density functional theory method coupled with the polarizable continuum model of solvation. In dilute acidic solutions, the Zundel‐type H5O2+ ion is mainly formed. In concentrated HCl solutions, the ions (H2O···H···O(H)Et)+ and (Et(H)O···H···O(H)Et)+ with the quasi‐symmetrical O···H+···O unit having O···O separation <2.45 Å appear. The first ion characterized by the IR‐intensive band around 1800 cm−1 is mainly formed in the 1 : 1 water–ethanol systems. The second ion exists in the 1 : 2 and 1 : 40 water–ethanol systems. Its spectroscopic signatures are the groups of the IR‐intensive bands around 800 and 1050 cm−1. In highly concentrated HCl solutions with the 1 : 40 water–ethanol ratio, a neutral Et(H)O···H+···Cl− complex exists. Copyright © 2013 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 82%

Section: Resultsmentioning

confidence: 99%

The structure and vibrational features of proton disolvates in water-ethanol solutions of HCl: the combined spectroscopic and theoretical study

Maiorov

Кислина

Rykounov

et al. 2013

J. Phys. Org. Chem.

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“…3 that the HC1 molecule is bound to the O atom of the DMF molecule. Changes in the p values for the lines corresponding to the vibrations of the N atom and the C atoms of the methyl groups are insignificant.…”

Section: Resultsmentioning

confidence: 98%

The structure of complexes of HCl withN,N-dimethylformamide based on polarization measurements in the Raman spectra

et al. 1998

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The Raman spectra of solutions of HCI in DMF were studied and the degree of depolarization of spectral lines was measured. Complexes of three types, 2DMF-HCI, DMF-HCI, and DMF-2HCI, are formed depending on the ratio of the components. Examination of the structure of the contour of the v(C=O) line showed that the acid-base interactions in the complexes occur through the O atom of the DMF molecule. On the basis of polarization measurements it was established that two DMF molecules in the 2DMF 9 HC1 complex are nonequivalent.Key words: dimethylformamide, hydrogen chloride, complexes; Raman spectra, degree of depolarization; solutions, acid-base interactions.Solutions of HCI in DMF are used as catalytic systems for a number of chemical reactions.l The efficiency of catalytic systems of such a type is determined by composition and structure of the DMF complexes with HC1. Previously, z the binary systems DMF--acid have been considered as solutions in which weak donoracceptor interactions play a significant role. Later, complexes 2DMF-HCI and DMF" HCI (1) with a strong quasi-symmetric H-bond as well as ionic pairs of composition DMF-2HCI (2) have been found 3 in solutions of HCI in DMF using the Multiple Attenuated Total Reflection (MATR) IR spectroscopy.Complex 1 is a quasi-ionic pair formed due to a strong quasi-symmetric H-bond between the O atom of the carbonyl group and the C1 atom. The formation of complex 2DMF" HCI (3) upon addition of one additional DMF molecule to complex 1 does not result in the cleavage of the strong quasi-symmetric H-bond between DMF and HCI. The two DMF molecules in 3 are nonequivalent. Previously, 4 the Raman spectra of complexes of such a type have been obtained for the first time and it was established that the formation of the complexes is accompanied by considerable changes in the frequencies and intensities of almost all lines of DMF molecules constituting them. In this work, Rarnan spectra of solutions of HCI in DMF were studied in a wider range of concentrations of the components and polarization measurements in the spectra were performed. ExperimentalThe procedures for purifying the reagents and preparing the solutions have been described previously)The Raman spectra of solutions of HCI in DMF were recorded on a DFS-24 spectrophotometer equipped with a double monochromator and an improved registration system. The 488 nm line of an LG-106M argon ion laser was used as the source of excitation; the other lines of the laser were suppressed by an interference filter. The polarization plane of linearly polarized laser light was rotated by 90 ~ with respect to the optical axis using a X/2 plate. In all experiments, the optical widths of the slits were 3 to 10 cm -t. To determine the relative degrees of depolarization of the lines (0) equal to the ratios of the line intensities obtained in the transversely and longitudinally polarized light, the spectrum of each solution was recorded 3 to 5 times in the correspondingly polarized light. The reproducibility of the intensity values was 10 to ...

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“…With optimal addition of HCl (up to 0.6 mM), the reaction essentially proceeds in a similar fashion, except for the delayed induction time (50 min), with peaks at around 590 and 905 nm (Figures b and S1), implying that both the proton and the chloride ion of HCl play a significant role. The proton is preferentially solvated by DMF, − whereas the chloride ions maintain the equilibrium concentration of AuCl 4 – ions, thus decreasing the net nucleation rate. To separate the roles played by proton and chloride, we replace HCl with equimolar amounts of HNO 3 and KCl (Figures S2 and S3).…”

Section: Resultsmentioning

confidence: 99%

Precursor-Driven Nucleation and Growth Kinetics of Gold Nanostars

Kedia

Kumar

2012

J. Phys. Chem. C

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Recently, seed-mediated approach has been widely utilized for synthesizing monodisperse gold nanostars well-known for plasmonic and sensing applications. Herein, we report a single step seedless/templateless organic synthesis procedure for the complex 3D gold nanostars with a high degree of size/shape control, involving the complexation of polyvinylpyrrolidone (PVP) in polar solvent N,N-dimethylformamide (DMF) and their reduction of AuCl4 – ions along with hydrochloric acid (HCl) as an effective mediator. On the basis of the kinetic optical absorption and Fourier transform infrared (FTIR) spectroscopy measurements, a convenient ligand exchange mechanism has been proposed for the first time to the best of our knowledge to understand the evolution of these complex shaped gold nanostructures. The coordination interaction among PVP and DMF as well as PVP–DMF–AuCl4 has been identified as the major driving factors influencing the temporal evolution of the size/shape-controlled gold nanostars.

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IR Study of ion-molecular interactions in a DMF-HCl system

Cited by 17 publications

References 4 publications

The structure and vibrational features of proton disolvates in water-ethanol solutions of HCl: the combined spectroscopic and theoretical study

The structure and vibrational features of proton disolvates in water-ethanol solutions of HCl: the combined spectroscopic and theoretical study

The structure of complexes of HCl withN,N-dimethylformamide based on polarization measurements in the Raman spectra

Precursor-Driven Nucleation and Growth Kinetics of Gold Nanostars

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