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Rajani P, Chandra S, Ramanathan N, Sundararajan K, Rao CB. Exploring the conformations of Dibutyl Phosphonate (DBP): A matrix isolation infrared spectroscopic and density functional theory studies. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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2
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Sarkar S, Chandra S, Suneesh A, Ramanathan N, Sundararajan K, Suresh A, Sivaraman N. Elucidating the extraction behaviour of tri-n-alkyl phosphates and tris(2-methylbutyl) phosphate with nitrates of uranyl and tetravalent metal ions from infrared spectroscopy and dynamic light scattering studies: A distinct correlation from conformational changes and variation in size of aggregates. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.131133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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3
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Sarkar S, Chandra S, Suryaprasad B, Ramanathan N, Sundararajan K, Suresh A. Conformational topography of tris(2-methylbutyl) phosphate and the influence of methyl branching at the non-hyperconjugative carbon on the conformational landscape: insights from matrix isolation infrared spectroscopy and DFT computations. Phys Chem Chem Phys 2020; 22:24372-24392. [PMID: 33084659 DOI: 10.1039/d0cp03403g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The branching of a methyl group in a linear chain has a profound influence on the conformational morphology as it wields a strong control in reducing a large number of conformations. To unravel the effect of branching on the second non-hyperconjugative carbon atom on the conformational landscape, the conformations of tris(2-methylbutyl)phosphate (T2MBP) were studied using Density Functional Theory (DFT) computations and matrix isolation infrared spectroscopy. Experimentally, T2MBP along with N2/Ar/Kr/Xe gases was effusively expanded and deposited at a low temperature of 12 K, which was subsequently probed using infrared spectroscopy. The computations of all the conformations were accomplished using the B3LYP level of theory with the 6-311++G(d,p) basis set. A dimethyl(2-methylbutyl) phosphate (DM2MBP) prototype, a molecule containing a single 2-methylbutyl moiety, was examined for its conformations. Computations predicted 18 and 9 conformations each for the 'gauche' and 'trans' families, respectively, in which the third branched carbon completely influences the orientation of the fourth carbon, which simplifies the conformational problem of DM2MBP. Of the 18 and 9 bunches each in the 'gauche' and 'trans' families, only 7 and 3 conformations, respectively, became energetically important, which when extrapolated to T2MBP resulted in 343 and 147 conformational possibilities. The factor of degeneracy further reduced these numbers and a total of 168 conformations effectively contribute to the conformational composition of T2MBP in the gas phase. The role of stereo electronic and steric factors prevalent in the conformational clusters of T2MBP was unravelled respectively using natural bond orbital and non-covalent interaction analyses.
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Affiliation(s)
- Subramee Sarkar
- Homi Bhabha National Institute, Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India.
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Gopi R, Ramanathan N, Sundararajan K. The structure of benzonitrile-water complex as unveiled by matrix isolation infrared spectroscopy: Is it linear or cyclic at low temperatures? J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Ramanathan N, Sarkar S, Sundararajan K. Prototypical cyclohexane dimers: spectroscopic evidence for σ stacking at low temperatures. Phys Chem Chem Phys 2020; 22:905-913. [DOI: 10.1039/c9cp05237b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In this work, the first unambiguous spectroscopic evidence for the existence of σ stacking interactions in cyclohexane dimers has been provided using matrix isolation infrared spectroscopy.
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Affiliation(s)
- N. Ramanathan
- Materials Chemistry and Metal Fuel Cycle Group
- Homi Bhabha National Institute
- Indira Gandhi Centre for Atomic Research
- Kalpakkam 603 102
- India
| | - Shubhra Sarkar
- Materials Chemistry and Metal Fuel Cycle Group
- Homi Bhabha National Institute
- Indira Gandhi Centre for Atomic Research
- Kalpakkam 603 102
- India
| | - K. Sundararajan
- Materials Chemistry and Metal Fuel Cycle Group
- Homi Bhabha National Institute
- Indira Gandhi Centre for Atomic Research
- Kalpakkam 603 102
- India
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Sarkar S, Ramanathan N, Sruthi PK, Sundararajan K. Conformations of diethyl ether and its interaction with pyrrole at low temperatures. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 213:361-369. [PMID: 30721851 DOI: 10.1016/j.saa.2019.01.076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/25/2019] [Accepted: 01/26/2019] [Indexed: 06/09/2023]
Abstract
Conformations of diethyl ether (DEE) were studied at low temperatures in N2 and Ar matrixes. Computations performed at B3LYP/aug-cc-pVDZ level of theory yielded three minima corresponding to tt, tg± and g±g± conformers of DEE. Of the three, the tt and tg± conformers of DEE were experimentally identified in N2 and Ar matrixes. Furthermore, hydrogen bonded complexes of pyrrole (py) with DEE have been investigated using Density Functional Theory (DFT) and matrix isolation infrared spectroscopy. Computations performed at B3LYP level of theory using aug-cc-pVDZ basis set on pyrrole with tt and tg± conformers of DEE gave py-DEE-tt and py-DEE-tg± complexes, both characterized by NH⋯O interaction. Experimental evidence for the formation of py-DEE-tt and py-DEE-tg± complexes was affirmed from the shifts in the NH stretching, NH bending regions of pyrrole and COC and CH stretching regions of DEE. NBO analysis was carried out to understand the charge-transfer delocalization interactions in the conformers of DEE and its hydrogen bonded complexes.
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Affiliation(s)
- Shubhra Sarkar
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam 603 102, India
| | - N Ramanathan
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam 603 102, India
| | - P K Sruthi
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam 603 102, India
| | - K Sundararajan
- Materials Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute, Kalpakkam 603 102, India.
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Ramanathan N, Sarkar S, Sankaran K, Sundararajan K. Photolysis of PCl 3
/POCl 3
with Oxygen Dopant Using 193 nm ArF Excimer at Low Temperatures: Oxygen Insertion through ‘Phosphadioxirane’ Pathway. ChemistrySelect 2019. [DOI: 10.1002/slct.201803318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Nagarajan Ramanathan
- Materials Chemistry and Metal Fuel Cycle group; Homi Bhabha National Institute; Indira Gandhi Centre for Atomic Research; Kalpkkam- 603102 India
| | - Shubhra Sarkar
- Materials Chemistry and Metal Fuel Cycle group; Homi Bhabha National Institute; Indira Gandhi Centre for Atomic Research; Kalpkkam- 603102 India
| | - Kannan Sankaran
- Materials Chemistry and Metal Fuel Cycle group; Homi Bhabha National Institute; Indira Gandhi Centre for Atomic Research; Kalpkkam- 603102 India
| | - Kalyanasundaram Sundararajan
- Materials Chemistry and Metal Fuel Cycle group; Homi Bhabha National Institute; Indira Gandhi Centre for Atomic Research; Kalpkkam- 603102 India
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Ramanathan N, Sarkar S, Sundararajan K, Chandrasekar A, Sankaran K, Suresh A. Influence of Branching on the Conformational Space: Case Study of Tri-sec-butyl Phosphate Using Matrix Isolation Infrared Spectroscopy and DFT Computations. J Phys Chem A 2018; 122:8229-8242. [DOI: 10.1021/acs.jpca.8b08157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- N. Ramanathan
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - Shubhra Sarkar
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - K. Sundararajan
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - Aditi Chandrasekar
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - K. Sankaran
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - A. Suresh
- Materials Chemistry & Metal Fuel Cycle Group, Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
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Ramanathan N, Sundararajan K, Viswanathan KS. Conformational Landscape of Tri-n-butyl Phosphate: Matrix Isolation Infrared Spectroscopy and Systematic Computational Analysis. J Phys Chem A 2017; 121:6108-6121. [DOI: 10.1021/acs.jpca.7b05006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- N. Ramanathan
- Materials
Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
| | - K. Sundararajan
- Materials
Chemistry and Metal Fuel Cycle Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu, India
| | - K. S. Viswanathan
- Department of Chemical Sciences, Indian Institute of Science Education & Research, Sector 81, Mohali 140306, Punjab, India
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Ramanathan N, Sundararajan K, Gopi R, Sankaran K. Photooxidation of Trimethyl Phosphite in Nitrogen, Oxygen, and para-Hydrogen Matrixes at Low Temperatures. J Phys Chem A 2017; 121:2121-2131. [DOI: 10.1021/acs.jpca.6b12296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- N. Ramanathan
- Materials
Chemistry and Metal Fuel Cycle Group and ‡Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, India
| | - K. Sundararajan
- Materials
Chemistry and Metal Fuel Cycle Group and ‡Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, India
| | - R. Gopi
- Materials
Chemistry and Metal Fuel Cycle Group and ‡Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, India
| | - K. Sankaran
- Materials
Chemistry and Metal Fuel Cycle Group and ‡Homi Bhabha National Institute, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102, India
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Sundararajan K, Gopi R, Ramanathan N. Conformations of propargyl alcohol and its interaction with acetylene: A matrix isolation infrared and DFT computations. J Mol Struct 2016. [DOI: 10.1016/j.molstruc.2016.05.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ramanathan N, Sundararajan K, Vidya K, Jemmis ED. Non-covalent C-Cl…π interaction in acetylene-carbon tetrachloride adducts: Matrix isolation infrared and ab initio computational studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2016; 157:69-78. [PMID: 26722673 DOI: 10.1016/j.saa.2015.12.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 11/23/2015] [Accepted: 12/14/2015] [Indexed: 06/05/2023]
Abstract
Non-covalent halogen-bonding interactions between π cloud of acetylene (C2H2) and chlorine atom of carbon tetrachloride (CCl4) have been investigated using matrix isolation infrared spectroscopy and quantum chemical computations. The structure and the energies of the 1:1 C2H2-CCl4 adducts were computed at the B3LYP, MP2 and M05-2X levels of theory using 6-311++G(d,p) basis set. The computations indicated two minima for the 1:1 C2H2-CCl4 adducts; with the C-Cl…π adduct being the global minimum, where π cloud of C2H2 is the electron donor. The second minimum corresponded to a C-H…Cl adduct, in which C2H2 is the proton donor. The interaction energies for the adducts A and B were found to be nearly identical. Experimentally, both C-Cl…π and C-H…Cl adducts were generated in Ar and N2 matrixes and characterized using infrared spectroscopy. This is the first report on halogen bonded adduct, stabilized through C-Cl…π interaction being identified at low temperatures using matrix isolation infrared spectroscopy. Atoms in Molecules (AIM) and Natural Bond Orbital (NBO) analyses were performed to support the experimental results. The structures of 2:1 ((C2H2)2-CCl4) and 1:2 (C2H2-(CCl4)2) multimers and their identification in the low temperature matrixes were also discussed.
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Affiliation(s)
- N Ramanathan
- Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India
| | - K Sundararajan
- Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, India.
| | - K Vidya
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695016, India
| | - Eluvathingal D Jemmis
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India.
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Gas phase reaction of phosphorus trichloride and methanol: Matrix isolation infrared and DFT studies. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2015.07.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Ramanathan N, Brahmmananda Rao CVS, Sankaran K, Sundararajan K. Unraveling the Conformational Landscape of Triallyl Phosphate: Matrix Isolation Infrared Spectroscopy and Density Functional Theory Computations. J Phys Chem A 2015; 119:4017-31. [DOI: 10.1021/acs.jpca.5b00889] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- N. Ramanathan
- Chemistry
Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | | | - K. Sankaran
- Chemistry
Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - K. Sundararajan
- Chemistry
Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
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15
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Ramanathan N, Sundararajan K, Sankaran K. Conformations of n-butyl imidazole: matrix isolation infrared and DFT studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 139:75-85. [PMID: 25554955 DOI: 10.1016/j.saa.2014.12.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 11/28/2014] [Accepted: 12/10/2014] [Indexed: 06/04/2023]
Abstract
Conformations of n-butyl imidazole (B-IMID) were studied using matrix isolation infrared spectroscopy by trapping in argon, xenon and nitrogen matrixes using an effusive nozzle source. The experimental studies were supported by DFT computations performed at the B3LYP/6-311++G(d,p) level. Computations identified nine unique minima for B-IMID, corresponding to conformers with tg(±)tt, tg(±)g(∓)t, tg(±)g(±)t, tg(±)tg(±), tg(±)tg(∓), tg(±)g(∓)g(∓), tg(±)g(±)g(±), tg(±)g(∓)g(±) and tg(±)g(±)g(∓) structures, given in order of increasing energy. Computations of the transition state structures connecting the higher energy conformers to the global minimum, tg(±)tt structure were carried out. The barriers for the conformer inter-conversion were found to be ∼2 kcal/mol. Natural Bond Orbital (NBO) analysis was performed to understand the reasons for conformational preferences in B-IMID.
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Affiliation(s)
- N Ramanathan
- Analytical Chemistry and Spectroscopy Section, Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - K Sundararajan
- Analytical Chemistry and Spectroscopy Section, Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India
| | - K Sankaran
- Analytical Chemistry and Spectroscopy Section, Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu, India.
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Kar BP, Ramanathan N, Sundararajan K, Viswanathan K. Matrix isolation and DFT study of the conformations of diethylcarbonate. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2014.04.044] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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17
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Ramanathan N, Kar BP, Sundararajan K, Viswanathan KS. Matrix Isolation Infrared and DFT Study of the Trimethyl Phosphite–Hydrogen Chloride Interaction: Hydrogen Bonding versus Nucleophilic Substitution. J Phys Chem A 2012; 116:12014-23. [DOI: 10.1021/jp306961m] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- N. Ramanathan
- Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu,
India
| | - Bishnu Prasad Kar
- Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu,
India
| | - K. Sundararajan
- Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu,
India
| | - K. S. Viswanathan
- Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu,
India
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18
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Conformations of dimethyl carbonate and its complexes with water: A matrix isolation infrared and ab initio study. J Mol Struct 2012. [DOI: 10.1016/j.molstruc.2012.05.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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