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Haddad B, Pandey DK, Singh DK, Paolone A, Drai M, Villemin D, Bresson S. Effect of isopropyl side chain branching and different anions on electronic structure, vibrational spectra, and hydrogen bonding of isopropyl-imidazolium-based ionic liquids: Experimental and theoretical investigations. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 291:122325. [PMID: 36634492 DOI: 10.1016/j.saa.2023.122325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 12/10/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
In the present work, four branched methylated, 1,2-dimethyl-3-isopropyl-imidazolium (i-[C3Dmim+]) and protonated,1-methyl-3-isopropyl-imidazolium (i-[C3mim+])-based ionic liquids (ILs) with varying anion (Br-, BF4-, PF6-, and NTf2-) were synthesized and investigated by NMR, infrared (IR) and Raman spectroscopy. Based on infrared and Raman spectroscopy, complete vibrational assignments have been performed. The IR and Raman analysis revealed that the vibrational spectra are virtually unaffected upon methylation, while significant frequency changes were observed by changing anion. Furthermore, to determine the electronic structure, energetic stability, and vibrational properties of these i-[C3Dmim]Y, i-[C3mim]Y (Y = Br, BF4, PF6, and NTf2) ion pairs, quantum chemical calculations including the dispersion correction method are performed both on single ions and on ionic couples. The calculated electron density was analyzed to expose non-covalent intra- and interionic interactions by the quantum theory of atoms in molecules (AIM) and interpreted in terms of both anion dependence and type of interaction. Computational results suggest that for all ionic couples the most energetically stable configuration is obtained with the anions located close to the C2 position of the imidazolium cation. However, in the case of i-[C3mim]NTf2 and i-[C3Dmim]BF4, similar energies were obtained in configurations 2 and 3 where the anion is located above the imidazolium ring. For i-[C3mim]Br a stronger hydrogen bond is predicted than for other studied ILs. Calculations indicate that a red shift of the CH stretching bands should occur due to hydrogen bonding; indeed, such displacement of bands is experimentally observed.
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Affiliation(s)
- Boumediene Haddad
- Department of Chemistry, Dr. Moulay Tahar University of Saida, 20000 Saida, Algeria; Chemistry Laboratory of Synthesis, Properties, and Applications (CLSPA-Saida), 20000 Saida, Algeria; Laboratoire de Chimie Moléculaire et Thio-organique, ENSICAEN, University of Caen, 6 Boulevard Maréchal Juin, 14050 Caen, France.
| | - Deepak K Pandey
- Department of Basic Sciences, Institute of Infrastructure Technology Research and Management, Ahmedabad 380026, India
| | - Dheeraj K Singh
- Department of Basic Sciences, Institute of Infrastructure Technology Research and Management, Ahmedabad 380026, India
| | - Annalisa Paolone
- Consiglio Nazionale delle Ricerche, Istituto dei SistemiComplessi, U.O.S. La Sapienza, Piazzale A. Moro 5, 00185 Roma, Italy
| | - Mokhtar Drai
- Chemistry Laboratory of Synthesis, Properties, and Applications (CLSPA-Saida), 20000 Saida, Algeria; Université DjillaliLiabes, BP 89, 22000 Sidi-Bel-Abbes, Algeria
| | - Didier Villemin
- Laboratoire de Chimie Moléculaire et Thio-organique, ENSICAEN, University of Caen, 6 Boulevard Maréchal Juin, 14050 Caen, France
| | - Serge Bresson
- Laboratoire de Physique des Systèmes Complexes, Université Picardie Jules Verne, 33 rue St Leu, 80039 Amiens cedex, France
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Das R, Pandey DK, Soumyashree S, P M, Nimma V, Bhardwaj P, K M MS, Singh DK, Kushawaha RK. Strong-field ionization of CH 3Cl: proton migration and association. Phys Chem Chem Phys 2022; 24:18306-18320. [PMID: 35880610 DOI: 10.1039/d2cp02494b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Strong-field ionization of CH3Cl using femtosecond laser pulses, and the subsequent two-body dissociation of CH3Cl2+ along Hn+ (n = 1-3) and HCl+ forming pathways, have been experimentally studied in a home-built COLTRIMS (cold target recoil ion momentum spectrometer) setup. The single ionization rate of CH3Cl was obtained experimentally by varying the laser intensity from 1.6 × 1013 W cm-2 to 2.4 × 1014 W cm-2 and fitted with the rate obtained using the MO-ADK model. Additionally, the yield of Hn+ ions resulting from the dissociation of all charge states of CH3Cl was determined as a function of intensity and pulse duration (and chirp). Next, we identified four two-body breakup pathways of CH3Cl2+, which are H+ + CH2Cl+, H2+ + CHCl+, H3+ + CCl+, and CH2+ + HCl+, using photoion-photoion coincidence. The yields of the four pathways were found to decrease on increasing the intensity from I = 4.2 × 1013 W cm-2 to 2I = 8.5 × 1013 W cm-2, which was attributed to enhanced ionization of the dication before it can dissociate. As a function of pulse duration (and chirp), the Hn+ forming pathways were suppressed, while the HCl+ forming pathway was enhanced. To understand the excited state dynamics of the CH3Cl dication, which controls the outcome of dissociation, we obtained the total kinetic energy release distributions of the pathways and the two-dimensional coincidence momentum images and angular distributions of the fragments. We inferred that the Hn+ forming pathways originate from the dissociation of CH3Cl dications from weakly attractive metastable excited states having a long dissociation time, while for the HCl+ forming pathway, the dication dissociates from repulsive states and therefore, undergoes rapid dissociation. Finally, quantum chemical calculations have been performed to understand the intramolecular proton migration and dissociation of the CH3Cl dication along the pathways mentioned above. Our study explains the mechanism of Hn+ and HCl+ formation and confirms that intensity and pulse duration can serve as parameters to influence the excited state dynamics and hence, the outcome of the two-body dissociation of CH3Cl2+.
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Affiliation(s)
- Rituparna Das
- Physical Research Laboratory Ahmedabad, Gujarat 380009, India.
| | - Deepak K Pandey
- Department of Basic Sciences, Institute of Infrastructure Technology Research And Management, Ahmedabad-380026, India.
| | | | - Madhusudhan P
- Physical Research Laboratory Ahmedabad, Gujarat 380009, India.
| | - Vinitha Nimma
- Physical Research Laboratory Ahmedabad, Gujarat 380009, India.
| | - Pranav Bhardwaj
- Physical Research Laboratory Ahmedabad, Gujarat 380009, India.
| | | | - Dheeraj K Singh
- Department of Basic Sciences, Institute of Infrastructure Technology Research And Management, Ahmedabad-380026, India.
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Pandey DK, Kuddushi M, Kumar A, Singh DK. Iron Oxide Nanoparticles Loaded Smart Hybrid Hydrogel for Anti-Inflammatory Drug Delivery: Preparation and Characterizations. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Jochim B, DeJesus L, Dantus M. Ultrafast disruptive probing: Simultaneously keeping track of tens of reaction pathways. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:033003. [PMID: 35365005 DOI: 10.1063/5.0084837] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Ultrafast science depends on different implementations of the well-known pump-probe method. Here, we provide a formal description of ultrafast disruptive probing, a method in which the probe pulse disrupts a transient species that may be a metastable ion or a transient state of matter. Disruptive probing has the advantage of allowing for simultaneous tracking of the yield of tens of different processes. Our presentation includes a numerical model and experimental data on multiple products resulting from the strong-field ionization of two different molecules, partially deuterated methanol and norbornene. The correlated enhancement and depletion signals between all the different fragmentation channels offer comprehensive information on photochemical reaction pathways. In combination with ion imaging and/or coincidence momentum imaging or as complementary to atom-specific probing or ultrafast diffraction methods, disruptive probing is a particularly powerful tool for the study of strong-field laser-matter interactions.
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Affiliation(s)
- Bethany Jochim
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Lindsey DeJesus
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Marcos Dantus
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
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