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Møllendal H, Samdal S, Matrane A, Guillemin JC. Synthesis, microwave spectrum, and dipole moment of allenylisocyanide (H2C═C═CHNC), a compound of potential astrochemical interest. J Phys Chem A 2011; 115:7978-83. [PMID: 21644586 DOI: 10.1021/jp204296n] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
An improved synthesis of a compound of potential astrochemical interest, allenylisocyanide (H(2)C═C═CHNC), is reported together with its microwave spectrum, which has been investigated in the 8-120 GHz spectral range to facilitate a potential identification in interstellar space. The spectra of the ground vibrational state and of five vibrationally excited states belonging to three different vibrational modes have been assigned for the parent species. A total of 658 transitions with a maximum value of J = 71 were assigned for the ground state and accurate values obtained for the rotational and quartic centrifugal distortion constants. The spectra of five heavy-atom ((13)C and (15)N) isotopologues were also assigned. The dipole moment was determined to be μ(a) = 11.93(16) × 10(-30) C m, μ(b) = 4.393(44) × 10(-30) C m, and μ(tot) = 12.71(16) × 10(-30) C m. The spectroscopic work has been augmented by theoretical calculations at the CCSD/cc-pVTZ and B3LYP/cc-pVTZ levels of theory. The theoretical calculations are generally in good agreement with the experimental results.
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102
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Guillemin JC. Organic Selenocyanates: Synthesis, Characterization and Uses in Chemistry and Biology. CURR ORG CHEM 2011. [DOI: 10.2174/138527211795656642] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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103
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Møllendal H, Samdal S, Guillemin JC. Microwave spectrum, conformational composition, and intramolecular hydrogen bonding of (2-chloroethyl)amine (ClCH2CH2NH2). J Phys Chem A 2011; 115:4334-41. [PMID: 21456567 DOI: 10.1021/jp201263c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The microwave spectrum of (2-chloroethyl)amine, ClCH(2)CH(2)NH(2), has been investigated in the 22-120 GHz region. Five rotameric forms are possible for this compound. In two of these conformers, denoted I and II, the Cl-C-C-N chain of atoms is antiperiplanar, with different orientations of the amino group. The link of the said atoms is synclinal in the three remaining forms, III-V, which differ with respect to the orientation of the amino group. The microwave spectra of four of these conformers, I-IV, have been assigned. In two of these rotamers, III and IV, the amino group is oriented in such a manner that rare and weak five-membered N-H···Cl intramolecular hydrogen bonds are formed. The geometries of conformers I and II preclude a stabilization by this interaction. The energy differences between the conformers were obtained from relative intensity measurements of spectral lines. The hydrogen-bonded conformer IV represents the global energy minimum. This rotamer is 0.3(7) kJ/mol more stable than the other hydrogen-bonded conformer III, 4.1(11) kJ/mol more stable than II, and 5.5(15) kJ/mol more stable than I. The spectroscopic work has been augmented by quantum chemical calculations at the CCSD/cc-pVTZ and MP2/6-311++G(3df,3pd) levels of theory. The CCSD rotational constants and energy differences are in good agreement with their experimental counterparts.
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104
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Hurtado M, Lamsabhi AM, Mó O, Yáñez M, Guillemin JC. Stability trends and tautomerization of chalcocyclopentadienes. The role of aromaticity. NEW J CHEM 2011. [DOI: 10.1039/c1nj20604d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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105
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Motiyenko RA, Margulès L, Goubet M, Møllendal H, Guillemin JC. High resolution millimeter-wave spectroscopy of vinyltellurol. J Phys Chem A 2010; 114:12202-7. [PMID: 21033752 DOI: 10.1021/jp108312w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The millimeter-wave rotational spectrum of vinyltellurol has been recorded and assigned for the first time. To support the spectrum assignment, high level ab initio calculations have been carried out. Geometries, total electronic energies, and harmonic vibrational frequencies have been determined at the MP2 level. A small-core relativistic pseudopotential basis set (cc-pVTZ-PP) was employed to describe the tellurium atom. Two stable conformers, synperiplanar (sp) and anticlinal (ac), have been identified. The sp conformer is planar with a small negative inertia defect of -0.025 u Å(2). The ac conformer was found to be nonplanar with a C-C-Te-H dihedral angle of about 140° from sp. This conformer exhibits a large amplitude motion associated with the torsion about the C-Te bond. The barrier to internal rotation is about 1 kJ/mol, according to the theoretical calculations. For the ac conformation, a torsional potential function consisting of quartic and quadratic terms of the torsional angle has been partially determined from the observed rotational constants.
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106
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Møllendal H, Konovalov A, Guillemin JC. Microwave spectrum, and conformational composition of (chloromethyl)phosphine (ClCH2PH2). J Phys Chem A 2010; 114:10612-8. [PMID: 20836524 DOI: 10.1021/jp106315u] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
(Chloromethyl)phosphine, (ClCH(2)PH(2)) has been studied by microwave spectroscopy at -30 °C in the 22-80 GHz spectral interval. The experimental study has been augmented by quantum chemical calculations at the MP2/aug-cc-pVQZ and B3LYP/aug-cc-pVTZ levels of theory. The spectra of the ground as well as of several vibrationally excited states of the (35)ClCH(2)PH(2) and (37)ClCH(2)PH(2) isotopologues of two rotameric forms, denoted I and II, have been assigned. These conformers have different orientations of the phosphino group. I has a symmetry plane, consisting of the Cl-C-P link of atoms, whereas the phosphino group is rotated out of this symmetry plane in II. Conformer I was found to be 4.3(5) kJ/mol more stable than II by relative intensity measurements. The rotational and quartic centrifugal distortion constants calculated using the MP2/aug-cc-pVQZ procedure are in very good agreement with their experimental counterparts. Less good agreement is found in the B3LYP/aug-cc-pVTZ calculations. Both computational procedures predict energy differences between I and II that are close to the experimental energy difference. It is suggested that I is the preferred form of this molecule because it is stabilized by weak intramolecular hydrogen bonding between the chlorine atom and the hydrogen atoms of the phosphino group. Repulsion between the lone electron pair of the phosphorus atom and the chlorine atom also stabilizes I relative to II.
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107
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González-Castrillo A, Hurtado M, Mó O, Yáñez M, Guillemin JC. The role of hyperconjugative π-aromaticity in the enhanced acidity of methyl-, silyl and germylcyclopentadienes. Mol Phys 2010. [DOI: 10.1080/00268976.2010.502138] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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108
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Turowski M, Crépin C, Gronowski M, Guillemin JC, Coupeaud A, Couturier-Tamburelli I, Piétri N, Kołos R. Electronic absorption and phosphorescence of cyanodiacetylene. J Chem Phys 2010; 133:074310. [DOI: 10.1063/1.3472978] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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109
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Bénidar A, Georges R, Guillemin JC, Mó O, Yáñez M. Infrared Spectra of a Species of Potential Prebiotic and Astrochemical Interest: Cyanoethenethiol (NC−CH═CH−SH). J Phys Chem A 2010; 114:9583-8. [DOI: 10.1021/jp105650e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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110
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Samdal S, Guillemin JC, Gundersen S. Molecular structure of trichloroethenylgermane, CH2=CH-GeCl3, as studied by gas-phase electron diffraction. experimental determination of the barrier of internal rotation of the trichlorogermyl group supplemented with quantum chemical calculations on CH2=CH-MX3 (M = C, Si, Ge, Sn, and X = H, Cl). J Phys Chem A 2010; 114:6331-5. [PMID: 20459079 DOI: 10.1021/jp101706z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The molecular structure of trichloroethenylgermane, CH(2)=CH-GeCl(3), has been determined by electron diffraction and supported by quantum chemical calculations on CH(2)=CH-MX(3) (M = C, Si, Ge, Sn and X = H, Cl). An equilibrium syn conformation with C(s) symmetry is obtained both experimentally and theoretically where one of the Ge-Cl bonds eclipses the C=C bond. The barrier of internal rotation about the C-Ge bond is determined to be V(3) = 5.3(7) kJ mol(-1) using a dynamic model to simulate the internal motion. The most important structure parameters (estimated r(e)/A and angle/degree) are: r(C-Ge) = 1.911(5), r(C=C) = 1.345(5), r(Ge-Cl7) = 2.122(2), <C=C-Ge = 120.4(5), <C-Ge-Cl7 = 111.0(2), and <Cl7-Ge-Cl8) = 109.4(5) where the Cl7 atom is in the C=C-Ge plane and the Cl8 atom is out of the C=C-Ge plane. Uncertainties are estimated total standard deviations (sigma(tot)) given as: sigma(tot) = [sigma(2)(scale) + (2sigma(lsq))(2)](1/2) for bond lengths where sigma(scale) = 0.001r and sigma(lsq) is the least-squares standard deviation using a diagonal weight matrix and sigma(tot) = 2sigma(lsq) for the other parameters. The assignment of some of the fundamental frequencies has been discussed. The internal agreement between the calculated molecular geometry obtained from B3LYP and MP2(F) using the cc-pVQZ basis set and to the experimental geometry is not good, whereas the molecular geometry obtained from a CCSD/cc-pVTZ calculation is in very good agreement with experimental geometry. This investigation shows that the gas electron-diffraction method is capable of determining the rotational barrier for small suitable molecules with acceptable accuracy.
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Németh B, Khater B, Guillemin JC, Veszprémi T. Differences Between Amine- and Phosphine-Boranes: Synthesis, Photoelectron Spectroscopy, and Quantum Chemical Study of the Cyclopropylic Derivatives. Inorg Chem 2010; 49:4854-64. [DOI: 10.1021/ic902180p] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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112
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Møllendal H, Konovalov A, Guillemin JC. Microwave Spectrum and Intramolecular Hydrogen Bonding of Propargyl Selenol (HC≡CCH2SeH). J Phys Chem A 2010; 114:5537-43. [DOI: 10.1021/jp101245f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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113
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Bellec A, Guillemin JC. Attempts to explain the self-disproportionation observed in the partial sublimation of enantiomerically enriched carboxylic acids. J Fluor Chem 2010. [DOI: 10.1016/j.jfluchem.2009.12.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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114
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Møllendal H, Konovalov A, Guillemin JC. Microwave and quantum chemical study of propargyl thiocyanate (HC[triple bond]CCH2SC[triple bond]N). J Phys Chem A 2010; 114:2300-5. [PMID: 20102176 DOI: 10.1021/jp9115244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The MW spectrum of propargyl thiocyanate (HC[triple bond]CCH(2)SC[triple bond]N) has been investigated for the first time in the 25-80 GHz spectral region at room temperature or at 0 degrees C. The spectra of the ground vibrational state and of the first excited state of the C-S torsional vibration have been assigned for one conformer. This rotamer, denoted ap, has a symmetry plane (C(s) symmetry) and an antiperiplanar arrangement for the C-C-S-C link of atoms. It has previously been claimed that a conformer that has a synclinal conformation for this chain of atoms is present in the gas in approximately the same concentration as ap (approximately 50% of the gas), but this is not supported by the present experiments, where it is shown that the synclinal rotamer, denoted sc, cannot be present in a concentration exceeding 1/3 of the total. It is therefore concluded that ap must be at least 3.0 kJ/mol more stable than sc. The spectroscopic work has been augmented by quantum chemical calculations at advanced B3LYP/aug-cc-pVQZ, B3LYP/6-311++G(3df,3pd), and MP2/aug-cc-pVTZ levels of theory. These theoretical calculations underestimate the energy difference between ap and sc and predict values for the conformationally important C-C-S-C dihedral angle of the hypothetical synclinal form that deviates by approximately 10 degrees.
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Motiyenko RA, Margulès L, Goubet M, Møllendal H, Konovalov A, Guillemin JC. First High Resolution Spectroscopic Studies and Ab Initio Calculations of Ethanetellurol. J Phys Chem A 2010; 114:2794-8. [DOI: 10.1021/jp912082b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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116
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Bellec A, Guillemin JC. A simple explanation of the enhancement or depletion of the enantiomeric excess in the partial sublimation of enantiomerically enriched amino acids. Chem Commun (Camb) 2010; 46:1482-4. [PMID: 20162155 DOI: 10.1039/b915610k] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the partial sublimation of three enantiomerically enriched amino acids, the ee of the sublimates can be explained by the ratio between the saturated vapor pressures of the racemate and the pure enantiomers.
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Hurtado M, Lamsabhi AM, Mó O, Yáñez M, Guillemin JC. Are cyclopentadienylberyllium, magnesium and calcium hydrides carbon or metal acids in the gas phase? Dalton Trans 2010; 39:4593-601. [DOI: 10.1039/b926653d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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118
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Hurtado M, Yáñez M, Guillemin JC. Enhanced acidity of cyclopenta-2,4-dienylborane and its Al and Ga analogues. The role of aromatization. Phys Chem Chem Phys 2009; 11:8759-66. [PMID: 20449020 DOI: 10.1039/b906045f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The intrinsic acidity of cyclopenta-2,4-dienylborane and its Al and Ga analogues has been compared to that of cyclopentadiene by means of B3LYP/6-311+G(3df,2p)//CCSD/6-311+G(d,p) calculations. Substitution of one of the H atoms of the C(sp(3))H(2) group of cyclopentadiene by an XH(2) (X = B, Al, Ga) leads to an acidity enhancement which is significantly large for the boron derivative (95 kJ mol(-1)); but much smaller for the Al and Ga containing analogues. This acidity enhancement reflects the stabilization of the anion, in the substituted derivatives, due to a significant reinforcement of the C-X bond. This enhancement is however smaller than expected because, although XH(2) (X = B, Al, Ga) substitution leads to a significant aromatization of the neutral compounds, the aromaticity significantly decreases upon deprotonation, whereas for the unsubstituted parent compound is the other way around. Cyclopenta-2,4-dienylborane and its Al and Ga analogues behave as highly fluxional systems.
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119
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Møllendal H, Konovalov A, Guillemin JC. Synthesis and Microwave Spectrum of (2-Chloroethyl)phosphine (ClCH2CH2PH2). J Phys Chem A 2009; 113:12904-10. [DOI: 10.1021/jp907199h] [Citation(s) in RCA: 9] [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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120
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Benidar A, Khater B, Guillemin JC, Gámez JA, Yáñez M. Gas-Phase Infrared Spectra of Vinyl Selenol and Vinyl Tellurol. J Phys Chem A 2009; 113:12857-63. [DOI: 10.1021/jp906075j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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121
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Noble-Eddy R, Masters SL, Rankin DWH, Wann DA, Robertson HE, Khater B, Guillemin JC. Primary Phosphines Studied by Gas-Phase Electron Diffraction and Quantum Chemical Calculations. Are They Different from Amines? Inorg Chem 2009; 48:8603-12. [DOI: 10.1021/ic901018s] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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122
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Marchal R, Bégué D, Pouchan C, Guillemin JC, Benidar A. Vibrational spectra of vinylarsine: A joint IR experimental and anharmonic theoretical study. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.08.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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123
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Konovalov A, Møllendal H, Guillemin JC. Microwave Spectrum, Structure, Barrier to Internal Rotation, and Dipole Moment of the Aziridine−Borane Complex (C2H5N−BH3). J Phys Chem A 2009; 113:8337-42. [DOI: 10.1021/jp904492u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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124
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125
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Hurtado M, Yánez M, Herrero R, Guerrero A, Dávalos JZ, Abboud JLM, Khater B, Guillemin JC. The ever-surprising chemistry of boron: enhanced acidity of phosphine.boranes. Chemistry 2009; 15:4622-9. [PMID: 19274692 DOI: 10.1002/chem.200802307] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The acidity-enhancing effect of BH(3) in gas-phase phosphineboranes compared to the corresponding free phosphines is enormous, between 13 and 18 orders of magnitude in terms of ionization constants. Thus, the enhancement of the acidity of protic acids by Lewis acids usually observed in solution is also observed in the gas phase. For example, the gas-phase acidities (GA) of MePH(2) and MePH(2)BH(3) differ by about 118 kJ mol(-1) (see picture).The gas-phase acidity of a series of phosphines and their corresponding phosphineborane derivatives was measured by FT-ICR techniques. BH(3) attachment leads to a substantial increase of the intrinsic acidity of the system (from 80 to 110 kJ mol(-1)). This acidity-enhancing effect of BH(3) is enormous, between 13 and 18 orders of magnitude in terms of ionization constants. This indicates that the enhancement of the acidity of protic acids by Lewis acids usually observed in solution also occurs in the gas phase. High-level DFT calculations reveal that this acidity enhancement is essentially due to stronger stabilization of the anion with respect to the neutral species on BH(3) association, due to a stronger electron donor ability of P in the anion and better dispersion of the negative charge in the system when the BH(3) group is present. Our study also shows that deprotonation of ClCH(2)PH(2) and ClCH(2)PH(2)BH(3) is followed by chloride departure. For the latter compound deprotonation at the BH(3) group is found to be more favorable than PH(2) deprotonation, and the subsequent loss of Cl(-) is kinetically favored with respect to loss of Cl(-) in a typical S(N)2 process. Hence, ClCH(2)PH(2)BH(3) is the only phosphineborane adduct included in this study which behaves as a boron acid rather than as a phosphorus acid.
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