The silicon-carbon double bond: a healthy rivalry between theory and experiment

Schaefer, Henry F.

doi:10.1021/ar00081a003

Cited by 127 publications

(31 citation statements)

References 49 publications

(18 reference statements)

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“…The early electron diffraction measurement 66 has been strongly criticized by Schaefer. 11 We agree with this critizism. The microwave-based structure of DMSE cannot be used as a reference for the SivC double bond length because only the parameters of the planar C 2 SiC skeleton were determined from the three rotational constants while all other structural parameters were constrained to their ab initio predictions.…”

Section: Discussionmentioning

confidence: 59%

“…3 In this last case, the variation is probably due to the bulky 1-adamantyl substituent which twists the double bond by 14.6°and thereby lengthens it. 11,65 Two measurements of the SivC double bond length have been made on DMSE ͑1,1-dimethylsilaethylene͒, one by microwave spectroscopy which led to a value of 1.692͑3͒ Å, 19 which is 0.012 Å less than our value in silene, and another one obtained by electron diffraction yielding a surprisingly large value of r g (SivC) ϭ 1.83(4) Å. 66 This difference cannot be explained only by the fact that electron diffraction does not lead to the true r e structure but to the r g one, which corresponds to bond lengths and angles at thermal equilibrium; the r e bond length should be smaller than r g by only 0.01-0.02 Å.…”

Section: Discussionmentioning

confidence: 99%

“…[7][8][9][10][11][12][13][14][15][16][17][18] In 1980, Goddard et al 8 calculated the structures and the energy separation for methylsilylene, CH 3 SiH, I and silylmethylene, H 3 SiCH, at the SCF/DZ(ϩd) level of theory. They found that methylsilylene was the most stable form by few kcal/mol.…”

Section: Introductionmentioning

confidence: 99%

“…In 1981, Hanamura et al 10 found for the first time that 1,1-dimethylsilene, Me 2 SivCH 2 , was more stable than MeSi-CH 2 Me. In 1982, Schaefer 11 details the silicon-carbon double bond compounds. Colvin et al 12 determined the optimized geometry and harmonic frequencies at the SCF and CISD level of theory with a DZϩP basis set.…”

Section: Introductionmentioning

confidence: 99%

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The equilibrium structure of silene H2C=SiH2 from millimeter wave spectra and from ab initio calculations

Bailleux

Bogey

Demaison

et al. 1997

The Journal of Chemical Physics

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Articles you may be interested inDistortion of ethyne on coordination to silver acetylide, C2H2AgCCH, characterised by broadband rotational spectroscopy and ab initio calculations Distortion of ethyne on formation of a π complex with silver chloride: C2H2Ag-Cl characterised by rotational spectroscopy and ab initio calculations Millimeter-wave spectroscopy and coupled cluster calculations for a new phosphorus-carbon chain: HC 5 P Silene, H 2 CSiH 2 , has been efficiently produced by pyrolysis of 5,6-bis͑trifluoromethyl͒-2-silabicyclo͓2.2.2͔octa-5,7-diene ͑SBO͒. Seven isotopomers have been observed by millimeterand submillimeter-wave spectroscopy. From the different sets of experimental molecular parameters and from ab initio calculations of the rovibrational interaction parameters, the equilibrium structure has been obtained by a least squares analysis of the rotational constants. The results are: r e (SivC) ϭ 1.7039(18) Å, r e (C-H) ϭ 1.0819(12) Å, r e (Si-H) ϭ 1.4671(9) Å, ЄHCSi ϭ 122.00(4)°, and ЄHSiC ϭ 122.39(3)°. This experimental structure is in excellent agreement with the equilibrium geometry calculated at the CCSD͑T͒ level of theory with a cc-pV͑Q,T͒Z basis set. This is the first experimental determination without any constraint of the SivC double bond length in the parent compound of the silaalkene family. A lifetime of 30 ms has been observed for this molecule in the gas phase at low pressure.

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Section: Discussionmentioning

confidence: 59%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The equilibrium structure of silene H2C=SiH2 from millimeter wave spectra and from ab initio calculations

Bailleux

Bogey

Demaison

et al. 1997

The Journal of Chemical Physics

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“…Ortho, meta, and para structures of nitrenophenylmethylene (C&CHN) and that of benzoazacyclobutene (benz [b]azete) and numbering of atomic positions. structures of the lowest singlet, triplet and quintet states of each isomer were fully optimized by means of this computational method (referred to as MCSCF (6,5)). At every optimized geometry, vibrational analyses were also performed numerically and the infrared (IR) absorption intensities of vibrational modes predicted theoretically l9 for comparison with the experimental re~u1ts.l~ For more reliable predictions of the relative stabilities of the isomers, MCSCF energy calculations using a larger active space are performed at the MCSCF(6,5) optimized geometries.…”

Section: Methods Of Calculationmentioning

confidence: 99%

FORS MCSCF Study on Nitrenophenylmethylene (C6H4CHN)

Koseki¹,

Tomioka²,

Toyota³

1994

J. Phys. Chem.

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Electronic structure calculations for the ortho, meta, and para isomers of nitrenophenylmethylene (c6H4-CHN) are carried out by using the full-optimized-reaction-space (FORS) multiconfiguration self-consistentfield (MCSCF) method with the STO-3G basis set. The ortho isomer is predicted to possess a singlet ground state with a bond-alternated structure. However, since the energy barrier for the isomerization reaction of the ortho structure to a bicyclic one (benzoazacyclobutene or benz[b]azete) is less than 10 kcaymol, the ortho isomer is considered to have a relatively short lifetime and hence to exist in the stable bicyclic form. The para isomer also has a singlet ground state with a bond-alternated structure, but it may easily react with molecular oxygen, as suggested experimentally, because the lowest triplet state is very close in energy to the singlet ground state. In marked contrast, the meta isomer has a quintet ground state, and this aspect is well reflected in the bonding, which shows no appreciable n conjugation between a benzene nucleus and two radical substituents.

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Silaacetylene: A possible target for experimental studies

Stegmann

Frenking

1996

J. Comput. Chem.

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The equilibrium geometries and transition states for interconversion of the CSiH2 isomers in the singlet electronic ground state are optimized at the MP2 and CCSD(T) levels of theory using a TZ2P basis set. The heats of formation, vibrational frequencies, infrared intensities, and rotational constants are also predicted. There are three energy minima on the CSiH2 potential energy surface. Energy calculations at CCSD(T)/TZ2P(fd) + ZPE predict that the global energy minimum is silavinylidene (1), which is 34.1 kcal mol−1 lower in energy than trans‐bent silaacetylene (2) and 84.1 kcal mol−1 more stable than the vinylidene isomer (3). The barrier for rearrangement 2→1 is calculated at the same level of theory to be 5.1 kcal mol−1, while for the rearrangement 3→2 a barrier of 2.7 kcal mol−1 is predicted. The natural bond orbital (NBO) population scheme indicates a clear polarization of the C(SINGLE BOND)Si bonds toward the carbon end. A significant ionic contribution to the C(SINGLE BOND)Si bonds of 1 and 2 is suggested by the NBO analysis. The C(SINGLE BOND)Si bond length of trans‐bent silaacetylene (2) is longer than previously calculated [1.665 Å at CCSD(T)/TZ2P)]. The calculated carbon‐silicon bond length of 2 is in the middle between the C(SINGLE BOND)Si double bond length of 1 (1.721 Å) and the C(SINGLE BOND)Si triple bond of the linear form HCSiH (4), which is 1.604 Å. Structure 4 is a higher‐order saddle point on the potential energy surface. © 1996 by John Wiley & Sons, Inc.

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The silicon-carbon double bond: a healthy rivalry between theory and experiment

Cited by 127 publications

References 49 publications

The equilibrium structure of silene H2C=SiH2 from millimeter wave spectra and from ab initio calculations

The equilibrium structure of silene H2C=SiH2 from millimeter wave spectra and from ab initio calculations

FORS MCSCF Study on Nitrenophenylmethylene (C6H4CHN)

Silaacetylene: A possible target for experimental studies

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