ESCA investigations of Group 4 derivatives. 4. Binding energies of hydrido(methyl)germanes and -silanes and of hydrido(halo)methylgermanes and -silanes

Drake, John E.; Riddle, Chris; Glavinčevski, Boris M.; Gorzelska, Krystyana; Henderson, H. E.

doi:10.1021/ic50186a071

Cited by 22 publications

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“…20 The most convenient route to form molecular organosilylcarbodiimides in high yields is the transamination of cyanamide with hexaorganodisilazanes as published by Vostokov et al in 1977: 21 It was found by Drake et al, 22 Reischmann et al, 23 and several other authors 17 that bis(trimethylsily)carbodiimide (R 3 SisNdCdNsSiR 3 , with R ) CH 3 ) itself is a very efficient starting material for the synthesis of other element carbodiimides. Thus, organoelement halides as well as pure element halides can be reacted with bis(trimethylsily)carbodiimide to form novel carbodiimides: 1,17,[23][24][25][26][27][28][29] The driving force of reaction 7 is the formation of stable (CH 3 ) 3 SiX, which can be easily separated from the formed element carbodiimide by distillation.…”

Section: Introductionmentioning

confidence: 99%

Inorganic Solid-State Chemistry with Main Group Element Carbodiimides

et al. 1998

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Organosilicon carbodiimides have been successfully applied as single-source precursor compounds for the synthesis of novel ternary Si-, C-, and N-containing solid phases. Their thermally induced decomposition gives either amorphous silicon carbonitrides or polycrystalline silicon nitride and silicon carbide mixtures, materials that are presently of technological interest for their exceptional hardness, strength, toughness, and high temperature resistance even in corrosive environments. This review is concerned with the synthesis, characterization, and thermal stability of element carbodiimides. The main part of this paper is focused on polymeric silicon-based carbodiimides obtained by the reaction of chloro(organo)silanes with bis(trimethylsilyl)carbodiimide. In the case of RSiCl 3 , novel poly(silylcarbodiimide) gels are formed. Starting from silicon tetrachloride, new crystalline SiCN phases (namely, SiC 2 N 4 and Si 2 CN 4 ), have been isolated. Their crystal structures as well as their thermal behavior in the range between room temperature and 1600 °C are discussed. Moreover, preliminary results on the synthesis of germanium-and boron-containing carbodiimides are reported. It is also shown that carbon-based carbodiimides can be obtained by the reaction of cyanuric halides with bis(trimethylsilyl)carbodiimide. These materials are investigated as precursors for the synthesis of new carbon nitrides with high hardness.

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Section: Introductionmentioning

confidence: 99%

Inorganic Solid-State Chemistry with Main Group Element Carbodiimides

et al. 1998

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“…Actually it follows from numerous publications [1][2][3][4][5][6][7][8][9][10] that the energies of the core electrone of the invariable atom A depend on X. This seeming paradox was analyzed in detail [1,6,11] in the literature on the X-ray electron spectroscopy and can be considered on the qualitative level by an example of the molecule AX 4 .…”

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confidence: 99%

“…Abundant data [1,3,4,[6][7][8][9]11] show that the experimental E values are directly proportional to the calculated values of the charge Q.…”

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“…The rapproachment of R C and X on a short distance induces in the cation-radicals R C ·+ ΒX and R C ·+ X a special interaction between the reaction center and the substituents: the polarization effect. Therefore for nonclassic series expression (9) transforms into the equation:…”

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“…It is seen from Table 4 that for all series (I-XV) in going from the two-parametric equations of the type (9) to three-parametric of the type (10) the statistic indices improve: the standard approximation error S Y decreases, and the correlation factor r grows. It means that, firstly, parameters σ I , σ R , and σ R + are suitable for the quantitative estimation of the inductive and resonance effects of substituents X in the cation-radicals Si ·+ X 4 arising on 2p-electron elimination from the Si atom.…”

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Binding energy of 2p-electrons of silicon atom. Substituents effects in Si-centered cation-radicals

2010

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The substituent effect was analyzed on the binding energy of 2p-electrons of the silicon atoms estimated by the X-ray electron spectroscopy or calculated by quantum chemistry method for 15 series of organosilicon compounds. It was established for the first time that the binding energy depended not only on the inductive and resonance effects of the substituents, but also on the polarization effect consisting in the electrostatic interaction of the positive charge on the silicon atom with the dipoles which this charge induced in the substituents. The contribution of the polarization effect reached 35%.X-ray electron spectropscopy is extensively used in the study of the energies binding the internal (core) electrons with the atomic nuclei in versatile molecules [1][2][3][4]. Let us consider the process occurring in the gas phase:Here AX n is a neutral molecule, A ·+ X n is a cationradical formed from AX n by the elimination of an internal electron from the central atom A under the action of an X-ray quantum hν, X are substituents not involved directly into the reaction, e is an electron.By definition [1, 5] the binding energy E of the internal electron is the following difference:Here E(A ·+ X n ) and E(AX n ) are total energies of the cation-radical and the molecule.Depending on the nature of the A atom (C, N, O, Br, …) and on the type of the internal electron (1s, 2p, 3d, …) the energy E varies in a wide range, from tens to thousands eV [2]. The investigation of the influence of the intramolecular interactions on the energy E provides the best information at the use of the so-called narrow series of compounds, for instance, CX 4 , OX 2 , BrX etc.In these series the central atom A is invariable, and the substituents X, on the contrary, change the donor-acceptor properties.At the first site the X substituents in the narrow series AX n should not affect the energy of the internal electrons of the A atom since these electrons virtually are not involved in the formation of the chemical bonds A-X. Actually it follows from numerous publications [1-10] that the energies of the core electrone of the invariable atom A depend on X. This seeming paradox was analyzed in detail [1,6,11] in the literature on the X-ray electron spectroscopy and can be considered on the qualitative level by an example of the molecule AX 4 .According to a simplified model in the molecule AX 4 the valence electrones of the A atom and X substituents are charged spheres of the radii R A and R X respectively, and R X > R A . The effective charge Q of the atom A creates within the sphere a potential Q/(4πε O R A ) affecting the core electrons of atom A. The charge Q is not localized on the A atom, but is partially transferred to the acceptor substituents X. Therefore the effect of the valence electrons of atom A and substituents X on the binding energy E of the core electrons is described by the equation:

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ChemInform Abstract: ESCA INVESTIGATIONS OF GROUP 4 DERIVATIVES. 4. BINDING ENERGIES OF HYDRIDO(METHYL)GERMANES AND ‐SILANES AND OF HYDRIDO(HALO)METHYLGERMANES AND ‐SILANES

Drake¹,

Riddle²,

Glavinčevski³

et al. 1978

Chemischer Informationsdienst

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ESCA investigations of Group 4 derivatives. 4. Binding energies of hydrido(methyl)germanes and -silanes and of hydrido(halo)methylgermanes and -silanes

Abstract: A steric effect of substituents in planar and tetrahedral NiX2L2 complexes has been attributed respectively to Ni-X16 and Ni-P17 bond lengthening.

Cited by 22 publications

References 3 publications

Inorganic Solid-State Chemistry with Main Group Element Carbodiimides

Inorganic Solid-State Chemistry with Main Group Element Carbodiimides

Binding energy of 2p-electrons of silicon atom. Substituents effects in Si-centered cation-radicals

ChemInform Abstract: ESCA INVESTIGATIONS OF GROUP 4 DERIVATIVES. 4. BINDING ENERGIES OF HYDRIDO(METHYL)GERMANES AND ‐SILANES AND OF HYDRIDO(HALO)METHYLGERMANES AND ‐SILANES

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