AM1 and PM3 semiempirical molecular orbital study of silatranes.

Csonka, Gábor I.; Hencsei, P.

doi:10.1016/0166-1280(93)87135-z

Cited by 18 publications

(7 citation statements)

References 19 publications

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“…Frequency analysis predicts that a separate Si N vibration frequency should not exist. For 1-methylsilatrane, the Si N stretching vibration (in the region of 280 cm 1 ) should be combined with the C N (at about 450 cm 1 ), Si O and Si C (at about 720 cm 1 ) vibrations 191 whereas for 1-chlorosilatrane a combined Cl Si N vibration should appear at 364 cm 1 192 .…”

Section: Quantum Mechanical Studiesmentioning

confidence: 98%

“…Most of them, together with results of frequency analyses based on semiempirical calculations 191,192 , show that no pure Si N vibration frequency exists. Thus, calculations of vibration spectra of 1-hydrosilatrane revealed that at least two completely symmetric vibrations of silatrane molecules should include the Si N vibration.…”

Section: Vibrational Spectramentioning

confidence: 98%

“…Calculations of the potential functions governing the Si N bond stretching motion made it possible to trace regularities in the variation of the atomic charges and stereoelectronic and orbital structure of silatranes with the change in the coordination number of the silicon atom and the degree of the Si N bonding 180,188,191,192,196 . It was found that the main changes in atomic charges upon variation in the Si N bond length occur on the O, N and X atoms, rather than on silicon.…”

Section: Quantum Mechanical Studiesmentioning

confidence: 99%

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Silatranes and Their Tricyclic Analogs

Pestunovich

Kirpichenko

Воронков

1998

PATAI'S Chemistry of Functional Groups

143

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Section: Quantum Mechanical Studiesmentioning

confidence: 98%

Section: Vibrational Spectramentioning

confidence: 98%

Section: Quantum Mechanical Studiesmentioning

confidence: 99%

See 1 more Smart Citation

Silatranes and Their Tricyclic Analogs

Pestunovich

Kirpichenko

Воронков

1998

PATAI'S Chemistry of Functional Groups

143

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“…Several theoretical studies, which focus on pentacoordinated silicon compounds, have been published. [21][22][23][24][25][26][27][28][29][30][31][32][33] The results reported by Schmidt and co-workers 29 show that the Hartree-Fock calculated structures for 3b and 3c have much longer Si r N bond distances than the gas-phase structures. Schmidt et al 29 suggest that the electron correlation energy treatments are important if discrepancies between theory and gas-phase experiments are to be removed.…”

Section: Introductionmentioning

confidence: 99%

Inductive Effects in Neutral Pentacoordinated Silicon Compounds Containing a Si ← N Dative Bond. A Theoretical Study

et al. 1999

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Using ab initio MP2 and DFT calculations, we have studied the structure of a series of pentacoordinated silicon compounds containing a Si r N dative bond and the influence of inductive effects on the Si r N bond. The study includes two series of model systems, namely, Si(NH 3 )X n Y 4-n (X ) OH, Y ) H or CH 3 ; n ranging from 0 to 4) and Si(NH 3 )(NH 2 )H 2 X (X ) Cl or H), methyl(2,2′,2′′-nitrilotriethoxy)silane, methyl(2,2′,3-nitrilodiethoxypropyl)silane, 8-(trifluorosilylamino)quinoline, 8-(trimethylsilylamino)quinoline, a dimer of Me 2 NSiH 2 Cl, and a pentamer of Me 2 NSiH 3 . All these structures have dative Si r N bonds. The nature of the bonds was analyzed using the Laplacian of the charge density distribution and the natural bond orbital (NBO) partitioning scheme. The calculations show that the dissociation energy of the Si r N dative bond in the model systems is always lower than 9 kcal mol -1 and that the Si r N bond length gets shorter as the number of electron-withdrawing groups linked to silicon increases. The different aggregation mode between the dimer of Me 2 NSiH 2 Cl and the pentamer of Me 2 NSiH 3 is also analyzed.

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“…Many theoretical studies have been reported on the equilibrium geometries of the 1-fluoro, 1-chloro, 1-methyl, hydroxysilatrane and 1-isothiocyatosilatrane. [9][10][11][12][13][14][15][16][17][18] The geometries of these molecules have been optimized by semiempirical (MNDO, PM3 and AM1), restricted Hartree-Fock (RHF), and density functional theory (DFT) calculations. The calculated N→Si bond lengths were much longer than the experimental values in all these studies.…”

Section: Introductionmentioning

confidence: 99%

Structures and N→Si Bond Characters of 1-Fluorosilatrane and the Silatranyl Cation

Lee

Bae²,

Do³

et al. 2002

Bulletin of the Korean Chemical Society

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The structures of 1-fluorosilatrane and the silatranyl cation were calculated by Hartree-Fock (HF), Mφller-Plesset second order (MP2), and various density functional theory (DFT) methods using many different basis sets, demonstrating that the SiN bonds in two species are quite different. The N→Si bond distance of 1fluorosilatrane from the hybrid DFT calculations (~2.32 Å) using the Perdew-Wang correlation functional agrees with the gas phase experimental value (2.324 Å), while other functionals yield larger distances. The MP2 bond distance (2.287 Å with 6-311G*) is shorter, and the HF one (2.544 Å with 6-311G*) larger than those of DFT calculations. The MP2 bond distance is in good agreement with experiment indicating that the electron correlations are crucial for the correct description of the N→Si interaction. The silatranyl cation is a stable local minimum on the potential energy surface in all methods employed suggesting that the cation could be a reaction intermediate. The SiN bond length for the cation is about 1.87 Å for all calculations tested implying that the SiN bond is mainly conventional. Bonding characteristics of the SiN bond in two species derived from the natural bond orbital analysis support the above argument based on calculated bond lengths.

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AM1 and PM3 semiempirical molecular orbital study of silatranes.

Cited by 18 publications

References 19 publications

Silatranes and Their Tricyclic Analogs

Silatranes and Their Tricyclic Analogs

Inductive Effects in Neutral Pentacoordinated Silicon Compounds Containing a Si ← N Dative Bond. A Theoretical Study

Structures and N→Si Bond Characters of 1-Fluorosilatrane and the Silatranyl Cation

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