76
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Leach S, Schwell M, Garcia GA, Bénilan Y, Fray N, Gazeau MC, Gaie-Levrel F, Champion N, Guillemin JC. Ionization photophysics and spectroscopy of dicyanoacetylene. J Chem Phys 2013; 139:184304. [PMID: 24320271 DOI: 10.1063/1.4826467] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photoionization of dicyanoacetylene was studied using synchrotron radiation over the excitation range 8-25 eV, with photoelectron-photoion coincidence techniques. The absolute ionization cross-section and detailed spectroscopic aspects of the parent ion were recorded. The adiabatic ionization energy of dicyanoacetylene was measured as 11.80 ± 0.01 eV. A detailed analysis of the cation spectroscopy involves new aspects and new assignments of the vibrational components to excitation of the quasi-degenerate A(2)Πg, B(2)Σg(+) states as well as the C(2)Σu(+) and D(2)Πu states of the cation. Some of the structured autoionization features observed in the 12.4-15 eV region of the total ion yield spectrum were assigned to vibrational components of valence shell transitions and to two previously unknown Rydberg series converging to the D(2)Πu state of C4N2(+). The appearance energies of the fragment ions C4N(+), C3N(+), C4(+), C2N(+), and C2(+) were measured and their heats of formation were determined and compared with existing literature values. Thermochemical calculations of the appearance potentials of these and other weaker ions were used to infer aspects of dissociative ionization pathways.
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77
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Samdal S, Møllendal H, Guillemin JC. Microwave spectrum and conformational properties of 4-isocyano-1-butyne (HC≡CCH2CH2N≡C). J Phys Chem A 2013; 117:10304-10. [PMID: 24003874 DOI: 10.1021/jp407126x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The microwave spectrum of 4-isocyano-1-butyne (HC≡CCH2CH2N≡C) has been investigated in the 12.4-77.6 GHz spectral region. The spectra of two rotamers denoted ap and sc were assigned. ap has an antiperiplanar arrangement for the C-C-C-N chain of atoms, whereas sc has synclinal conformation for this link. The ground state spectrum and three vibrationally excited state spectra of the lowest torsional vibration were assigned for ap, while the ground vibrational state spectrum was assigned for sc. The C-C-C-N dihedral angle was found to be 64.5(30)° in sc and exactly 180° in ap. ap was determined to be 2.9(6) kJ/mol lower in energy than sc from relative intensity measurements. The microwave study has been augmented with ab initio and DFT calculations employing the CCSD(T), MP2, and B3LYP methods with the cc-pVTZ basis set. A Natural Bond Order analysis has also been performed. Most, but not all, of the quantum chemical predictions agree satisfactorily with the experimental results.
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78
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Cheikh Sid Ely S, Morales SB, Guillemin JC, Klippenstein SJ, Sims IR. Low Temperature Rate Coefficients for the Reaction CN + HC3N. J Phys Chem A 2013; 117:12155-64. [DOI: 10.1021/jp406842q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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79
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Tarasevych AV, Sorochinsky AE, Kukhar VP, Chollet A, Daniellou R, Guillemin JC. Partial sublimation of enantioenriched amino acids at low temperature. Is it coming from the formation of a euatmotic composition of the gaseous phase? J Org Chem 2013; 78:10530-3. [PMID: 24067155 DOI: 10.1021/jo4017474] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The partial sublimation of enantioenriched amino acids was performed slowly at low temperature with the aim to determine the rules of sublimation of these compounds. Although the formation of a euatmotic composition of the gaseous phase starting from DL + L mixtures of Leu, Pro, and Phe can be deduced from the enantiomeric excess of sublimates, the behavior of the kinetic conglomerate explains the results for D + L mixtures of Ala, Leu, Val, and Pro. Consequently, the enantiomeric excess of the partial sublimate is dependent not only on the studied compound but also on the composition of the starting mixture.
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80
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Samdal S, Møllendal H, Guillemin JC. Microwave Spectrum, Conformational Properties, and Dipole Moment of Cyclopropylmethyl Isocyanide (C3H5CH2NC). J Phys Chem A 2013; 117:5073-81. [DOI: 10.1021/jp403374k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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81
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Tarasevych AV, Sorochinsky AE, Kukhar VP, Guillemin JC. Deracemization of amino acids by partial sublimation and via homochiral self-organization. ORIGINS LIFE EVOL B 2013; 43:129-35. [PMID: 23690241 DOI: 10.1007/s11084-013-9333-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/24/2013] [Indexed: 10/26/2022]
Abstract
Deracemization of a 50/50 mixture of enantiomers of aliphatic amino acids (Ala, Leu, Pro, Val) can be achieved by a simple sublimation of a pre-solubilized solid mixture of the racemates with a huge amount of a less-volatile optically active amino acid (Asn, Asp, Glu, Ser, Thr). The choice of chirality correlates with the handedness of the enantiopure amino acids--Asn, Asp, Glu, Ser, and Thr. The deracemization, enantioenrichment and enantiodepletion observed in these experiments clearly demonstrate the preferential homochiral interactions and a tendency of natural amino acids to homochiral self-organization. These data may contribute toward an ultimate understanding of the pathways by which prebiological homochirality might have emerged.
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82
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Samdal S, Møllendal H, Guillemin JC. Synthesis, microwave spectrum, and conformational properties of 2-fluoroethyl azide (FCH2CH2N3). J Phys Chem A 2013; 117:1935-40. [PMID: 23379369 DOI: 10.1021/jp312227t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A novel synthesis producing neat 2-fluoroethyl azide (FCH2CH2N3) is described. A conformational analysis using microwave spectroscopy augmented by quantum chemical calculations at the CCSD(T)/cc-pVTZ, B3LYP/aug-cc-pVTZ, and B3LYP/cc-pVTZ levels of theory has been performed for this compound. The spectra of the ground vibrational state and two vibrationally excited states of one rotameric form were assigned. A large number of transitions was assigned, and very accurate values were obtained for the rotational and quartic centrifugal distortion constants. The identified conformer has synclinal orientations for the F-C-C-N and C-C-N-N chains of atoms bringing the fluorine atom and the azido group into close proximity. It is concluded from consideration of absolute intensities that this conformer is indeed the preferred form of the molecule in accord with the theoretical calculations. The experimental and CCSD(T) rotational constants are in very good agreement, whereas much larger discrepancies were seen for the experimental and B3LYP quartic centrifugal distortion constants.
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83
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Demaison J, Jahn MK, Cocinero EJ, Lesarri A, Grabow JU, Guillemin JC, Rudolph HD. Accurate Semiexperimental Structure of 1,3,4-Oxadiazole by the Mixed Estimation Method. J Phys Chem A 2013; 117:2278-84. [DOI: 10.1021/jp400505v] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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84
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Lamsabhi AM, Mó O, Yáñez M, Guillemin JC. Conformational preferences of RCH2CH2CN (R = CH3, F, Cl) cyanides and their corresponding isocyanides. Struct Chem 2013. [DOI: 10.1007/s11224-013-0209-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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85
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Németh B, Guégan JP, Veszprémi T, Guillemin JC. Trimethylaluminum and Borane Complexes of Primary Amines. Inorg Chem 2012; 52:346-54. [DOI: 10.1021/ic302091t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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86
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Martín-Sómer A, Lamsabhi AM, Yáñez M, Dávalos JZ, González J, Ramos R, Guillemin JC. Can an Amine Be a Stronger Acid than a Carboxylic Acid? The Surprisingly High Acidity of Amine-Borane Complexes. Chemistry 2012; 18:15699-705. [DOI: 10.1002/chem.201202192] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Indexed: 11/08/2022]
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87
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88
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Samdal S, Møllendal H, Guillemin JC. Microwave spectra and barriers to internal rotation of Z- and E-1-propenyl isocyanide. J Phys Chem A 2012; 116:8833-9. [PMID: 22839412 DOI: 10.1021/jp304227u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A synthetic procedure yielding a mixture of Z- and E-1-propenyl isocyanide (CH(3)CH═CHNC) is described. The microwave spectrum of this mixture has been recorded in the 12-100 GHz spectral range, and the spectra of the Z and E isomers have been assigned for the first time. Most transitions of the Z form were split into two components of equal intensity due to tunneling of the methyl group, which allowed the barrier to internal rotation of this group to be determined as 4.0124(12) kJ/mol by fitting 568 transitions with a maximum value of J = 46 using the computer program Xiam. This fit had a root-mean-square deviation as large as 4.325. The same transitions were therefore fitted anew using the more sophisticated program Erham. This fit has a rms deviation marginally better (4.136) than the Xiam fit. No split MW lines were found for E-1-propenyl isocyanide. The absence of splittings is ascribed to a barrier to internal rotation of the methyl group that is significantly higher than the barrier of the Z isomer. It is concluded that the barrier must be larger than 6 kJ/mol for the E form. The experimental work was augmented by quantum chemical calculations at CCSD/cc-pVTZ, B3LYP/cc-pVTZ, and MP2/cc-pVTZ levels of theory. The CCSD method predicts rotational constants of the Z and E forms well. The B3LYP barriers to internal rotation of a series of substituted propenes were calculated and found to be in good agreement with experiments. Calculations of the quartic centrifugal distortion constants of the two 1-propenyl isocyanides by the B3LYP and MP2 methods were less successful.
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89
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Goubet M, Motiyenko RA, Margulès L, Guillemin JC. Synthesis, High-Resolution Millimeter-Wave Spectroscopy, and Ab Initio Calculations of Ethylmercury Hydride. J Phys Chem A 2012; 116:5405-9. [DOI: 10.1021/jp302617y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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90
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Møllendal H, Samdal S, Bunkan AJC, Guillemin JC. Synthesis and Microwave Spectrum of Vinyl Isoselenocyanate (H2C═CHNCSe), a Compound with a Quasilinear CNCSe Chain. J Phys Chem A 2012; 116:4074-81. [DOI: 10.1021/jp301803z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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91
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Møllendal H, Margulès L, Motiyenko RA, Larsen NW, Guillemin JC. Rotational Spectrum and Conformational Composition of Cyanoacetaldehyde, a Compound of Potential Prebiotic and Astrochemical Interest. J Phys Chem A 2012; 116:4047-56. [DOI: 10.1021/jp212306z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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92
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Hurtado M, Lamsabhi AM, Mó O, Yáñez M, Guillemin JC. Inside Cover: On the Origin of the Enhanced Acidity of Chalcocyclopentadienes (Cyclopentadiene Chalcogenols) in the Gas Phase (ChemPhysChem 5/2012). Chemphyschem 2012. [DOI: 10.1002/cphc.201290020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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93
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Hurtado M, Lamsabhi AM, Mó O, Yáñez M, Guillemin JC. On the Origin of the Enhanced Acidity of Chalcocyclopentadienes (Cyclopentadiene Chalcogenols) in the Gas Phase. Chemphyschem 2012; 13:1167-72. [DOI: 10.1002/cphc.201101021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Indexed: 11/08/2022]
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94
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Abboud JLM, Németh B, Guillemin JC, Burk P, Adamson A, Nerut ER. Dihydrogen Generation from Amine/Boranes: Synthesis, FT-ICR, and Computational Studies. Chemistry 2012; 18:3981-91. [DOI: 10.1002/chem.201102611] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 11/20/2011] [Indexed: 11/06/2022]
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95
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Begue D, Pouchan C, Guillemin JC, Benidar A. Anharmonic treatment of vibrational resonance polyads—the diborane: a critical case for numerical methods. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1122-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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96
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Motiyenko RA, Margulès L, Guillemin JC. High Resolution Millimeter-Wave Spectroscopy of Cyclopropylphosphine–Borane. J Phys Chem A 2012; 116:1565-70. [DOI: 10.1021/jp211611t] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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97
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Møllendal H, Samdal S, Guillemin JC. Microwave spectrum and conformational composition of 3-fluoropropionitrile (FCH2CH2CN). J Phys Chem A 2012; 116:1015-22. [PMID: 22171601 DOI: 10.1021/jp210932k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The microwave spectrum of 3-fluoropropionitrile, FCH(2)CH(2)C≡N, has been investigated in the whole 17-75 GHz spectral region. Selected portions of the spectrum in the 75-95 GHz have also been recorded. The microwave spectra of the ground state as well as of three vibrationally excited states of each of two conformers have been assigned. The spectra of the vibrationally excited states belong to the lowest torsional and bending vibrations. The F-C-C-C chain of atoms is exactly antiperiplanar in one of these rotamers and synclinal in the second conformer. The F-C-C-C dihedral angle is 65(2)° in the synclinal form. The energy difference between the two forms has been obtained from relative intensity measurements performed on microwave transitions. It was found that the antiperiplanar conformer is more stable than the synclinal form by 1.4(5) kJ/mol. It is argued that the gauche effect is a significant force in this compound. Quantum chemical calculations at the high CCSD(full)/cc-pVTZ, MP2(full)/cc-pVTZ, and B3LYP/cc-pVTZ levels of theory have been performed. Most, but not all, of the theoretical predictions are in good agreement with experiment.
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98
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Chrostowska A, Matrane A, Maki D, Khayar S, Ushiki H, Graciaa A, Belachemi L, Guillemin JC. Are Unsaturated Isocyanides so Different from the Corresponding Nitriles? Chemphyschem 2011; 13:226-36. [DOI: 10.1002/cphc.201100672] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Indexed: 11/11/2022]
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99
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Møllendal H, Samdal S, Guillemin JC. Microwave Spectrum and Conformational Composition of 2-Chloroethylisocyanide. J Phys Chem A 2011; 115:13474-81. [DOI: 10.1021/jp208580m] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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100
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Samdal S, Møllendal H, Guillemin JC. Microwave spectrum and conformational composition of 2-fluoroethylisocyanide. J Phys Chem A 2011; 115:9192-8. [PMID: 21718075 DOI: 10.1021/jp205024s] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The microwave spectrum of 2-fluoroethylisocyanide, FCH(2)CH(2)N≡C, has been investigated in the whole 50-120 GHz spectral region. Selected portions of the spectrum in the range of 18-50 GHz have also been recorded. The microwave spectra of the ground state and vibrationally excited states of two conformers have been assigned. Accurate spectroscopic constants have been derived from a large number of microwave transitions. The F-C-C-N chain of atoms is antiperiplanar in one of these rotamers and synclinal in the second conformer. The energy difference between the two forms was obtained from relative intensity measurements. It was found that the synclinal conformer is favored over the antiperiplanar form by 0.7(5) kJ/mol. Quantum chemical calculations at the high CCSD/cc-pVTZ and B3LYP/cc-pVTZ levels of theory were performed. Most, but not all, of the spectroscopic constants predicted in these calculations are in good agreement with the experimental counterparts. The theoretical calculations correctly indicate that the F-C-C-N dihedral angle in the synclinal form is about 67° but underestimate the magnitude of the gauche effect and erroneously predict the antiperiplanar rotamer to be 1.3-1.6 kJ/mol more stable than the synclinal conformer.
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