Infrared Spectroscopic and dielectrometric investigation of the molecular geometry of isocyanato- and isothiocyanato-silane derivatives

Veszprémi, Tamás; Nagy, József; Barta, I.; Zsombok, G.

doi:10.1016/s0022-328x(00)83504-4

Cited by 18 publications

(5 citation statements)

References 24 publications

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“…[7] A similar quasi-linearity was found for the SiNCO skeleton of the trimethylisocyanate molecule from a microwave investigation, [6] which is consistent with the vibrational data. [9,10] Therefore, the conclusion for the dimethylsilylisocyanate that the SiNC bend is linear or near linear is consistent with the structural determination for the corresponding linkage for similar molecules. Further support for the quasi-linearity for the SiNCO moiety is provided from the MP2 ab initio predictions (Table 4) from the calculation with relatively large basis set such as the 6-311G(2df,2pd) both with and without diffuse function, in which case the optimization of the gauche and cis conformers lead to a linear form with the SiNCO skeleton 180 • .…”

Section: Discussionsupporting

confidence: 82%

Raman and infrared spectra, conformational stability, ab initio calculations and vibrational assignment of dimethylsilylisocyanate

Guirgis

Zhou

Durig

2009

J Raman Spectroscopy

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The Raman (3200-30 cm −1 ) and/or infrared spectra (3500 to 400 cm −1 ) of gaseous, liquid and solid dimethylsilylisocyanate, (CH 3 ) 2 Si(H)NCO, have been recorded. The MP2(full) calculations, employing a variety of basis sets with and without diffusion functions, have been used to predict the structural parameters, conformational stability, vibrational fundamental wavenumbers, Raman activities, depolarization values and infrared intensities to support the vibrational assignment. The low wavenumber Raman spectrum of the gas with a significant number of Q-branches for the SiNC(O) bend is consistent with an essentially linear SiNCO moiety. The ab initio calculations supported this conclusion as all possible orientations of the NCO moiety lead to nearly the same energy. This result is at variance with the conclusion from the electron diffraction study that the heavy atom skeleton was bent with an angle of 152(5) • with one stable cis conformer. It is believed that this reported angle difference from 180 • is due to the shrinkage effect. The SiH distance of 1.486 Å has been obtained from the isolated SiH stretching wavenumber. From the adjustment of the ab initio MP2(full)/6-311+G(d,p) predicted structural parameters, a proposed structure is reported, which is expected to give rotational constants within a few megahertz of the actual ones. These experimental and theoretical results are compared with the corresponding quantities of similar molecules.

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Section: Discussionsupporting

confidence: 82%

Raman and infrared spectra, conformational stability, ab initio calculations and vibrational assignment of dimethylsilylisocyanate

Guirgis

Zhou

Durig

2009

J Raman Spectroscopy

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“…On the high-vacuum line, the tube was degassed and 1 atm of carbon monoxide was added. The tube was thawed and shaken, and the products were identified as (η 5 -C 5 H 3 -1,3-(SiMe 3 ) 2 ) 2 Ti(CO) 2 and Me 3 SiNCO on the basis of comparison to literature data . (η 5 -C 5 H 3 -1,3-(SiMe 3 ) 2 ) 2 Ti(CO) 2 : 1 H NMR (benzene- d 6 ): δ 0.21 (s, 36H, Si Me 3 ), 5.14 (s, 4H, Cp), 5.37 (s, 2H, Cp).…”

Section: Methodsmentioning

confidence: 99%

Synthesis of a Base-Free Titanium Imido and a Transient Alkylidene from a Titanocene Dinitrogen Complex. Studies on TiNR Hydrogenation, Nitrene Group Transfer, and Comparison of 1,2-Addition Rates

et al. 2004

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The synthesis and reactivity of the end-on bound dinitrogen complex [(η 5 -C 5 H 3 -1,3-(SiMe 3 ) 2 ) 2 Ti] 2 (µ 2 ,η 1 ,η 1 -N 2 ) is described. The solid state structure of the dinitrogen compound reveals a weakly activated end-on bound N 2 ligand with an N-N bond length of 1.164(5) Å. Displacement of the N 2 ligand by organic azides has been used to prepare monomeric, basefree titanocene imido complexes, (η 5 -C 5 H 3 -1,3-(SiMe 3 ) 2 ) 2 TidNR (R ) SiMe 3 , 2,4,6-Me 3 -C 6 H 2 ). While unreactive toward C-H bonds, the Ti-N linkage is readily hydrogenated and participates in group transfer reactions with unsaturated organic molecules such as carbon monoxide and benzophenone. Reaction of the N 2 complex with Ph 2 CN 2 allowed isolation of (η 5 -C 5 H 3 -1,3-(SiMe 3 ) 2 ) 2 Ti(N 2 CPh 2 ), which exists as a mixture of interconverting η 2 and η 1 isomers in solution. The diazoalkane complex also participates in "imido-like" reactivity, producing (η 5 -C 5 H 3 -1,3-(SiMe 3 ) 2 ) 2 Ti(NHNdCPh 2 )H upon addition of H 2 . Changing the diazoalkane to Me 3 SiCHN 2 resulted in isolation of the double cyclometalated titanocene (η 5 -C 5 H 3 -η 1 -1-SiMe 2 CH 2 -3-SiMe 3 ) 2 Ti, arising from facile intramolecular C-H activation of the cyclopentadienyl substituent by a transient titanocene alkylidene.

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“…In the broadband scan, characteristic 14 N nuclear quadrupole hyperfine structure gave rise to easily recognizable splitting patterns allowing relatively straightforward initial identification of the J = 1 10 0 00 and J = 2 11 1 01 c-type transitions. The experimental A rotational constant was significantly higher than originally predicted for the trans-HSiNC conformer, which of course has marginally poorer energy.…”

Section: The Rotational Spectrummentioning

confidence: 99%

“…Owing to the differing types of vibrational averaging, electron diffraction (ED) results can lead to considerably different structures to those from high resolution (MW and IR) spectroscopy. Some simple cases where this is exemplified are MeNCS [6], H 3 SiNCO [6][7][8][9][10], H 3 SiNCS [7,8,[10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

The molecular structure of difluoroisocyanato silane: A combined microwave spectral and theoretical study

Guirgis

Wang

Lirjoni

et al. 2010

Journal of Molecular Structure

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Infrared Spectroscopic and dielectrometric investigation of the molecular geometry of isocyanato- and isothiocyanato-silane derivatives

Cited by 18 publications

References 24 publications

Raman and infrared spectra, conformational stability, ab initio calculations and vibrational assignment of dimethylsilylisocyanate

Raman and infrared spectra, conformational stability, ab initio calculations and vibrational assignment of dimethylsilylisocyanate

Synthesis of a Base-Free Titanium Imido and a Transient Alkylidene from a Titanocene Dinitrogen Complex. Studies on TiNR Hydrogenation, Nitrene Group Transfer, and Comparison of 1,2-Addition Rates

The molecular structure of difluoroisocyanato silane: A combined microwave spectral and theoretical study

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