Theoretical Aspects of Compounds Containing<scp>Si</scp>,<scp>Ge</scp>,<scp>Sn</scp>and<scp>Pb</scp>

Karni, Miriam; Apeloig, Yitzhak; Kapp, Jürgen; Schleyer, Paul von Ragué

doi:10.1002/9780470682531.pat0235

Cited by 4 publications

(3 citation statements)

References 624 publications

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“…This is consistent with the previouh conclusion that because of the large size and the inner-shell electron's shielding in silicon atoms, the overlap between p z -orbitals in the relevant molecules is negligibly small, and thus tends to not form π-bonds preferentially [27]. This feature greatly influences the valence electrons' hybridization, changing it from sp 2 for carbon atoms to sp 3 -like for silicon [28] when p z electrons become effectively unpaired.…”

Section: Peculiarities Of the N D (R) Graphs Of C=c Si=c And Si=si supporting

confidence: 88%

Silicene is a phantom material

Sheka¹

2016

Nanosystems: Phys. Chem. Math.

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The paper presents a comparative consideration of sp 2 nanocarbons and their silicon and higher tetrels analogues from the viewpoint of the spin molecular theory taking into account the electron correlation in open-shell molecules. High radicalization of silicene and quantum instability of flat honeycomb 2D structures of germanene and stanene make all the species phantom materials leaving graphene the only one-atom thick 2D solid free of the crucial restrictions.

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Section: Peculiarities Of the N D (R) Graphs Of C=c Si=c And Si=si supporting

confidence: 88%

Silicene is a phantom material

Sheka¹

2016

Nanosystems: Phys. Chem. Math.

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“…Synthesis and structure of stable unsaturated compounds of heavy group-14 elements is one of the primary subjects of both experimental and theoretical main-group element chemistry; see reviews of experimental [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and theoretical aspects [20][21][22][23][24]. Since the first synthesis of stable digermenes and distannenes by Lappert et al [25][26][27] and a stable disilene by West et al [28], a number of heavy alkenes (R 2 E=ER 2 , E, E' = Si, Ge, Sn, and Pb) have been synthesized and their unusual structures and properties have been revealed.…”

Section: Introductionmentioning

confidence: 99%

Structure and Reactions of an Isolable Ge=Si Doubly Bonded Compound, Tetra(t-butyldimethylsilyl)germasilene

Iwamoto

Okita

Yoshida

et al. 2010

Silicon

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Tetra(t-butyldimethylsilyl)germasilene (8b) was synthesized using di(t-butyldimethylsilyl)hydridogermyllithium prepared by the germa-metallation of the corresponding dihydridogermane. Tetrasilylgermasilene 8b was obtained as single crystals by recrystallization from hexane at room temperature. The molecular structure of 8b is similar to those of the corresponding disilene 8a and digermene 8c but with an intermediate unsaturated bond length and twist angle between those of 8a and 8c. The reactions of 8b with methanol and 2,3-dimethylbutadiene gave the corresponding adducts. Equilibrium between 8b and the corresponding (trisilylsilyl)(silyl)germylene is suggested by the reaction of 8b with triethylsilane giving the germylene insertion product into the Si-H bond.

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“…Elemental boron and silicon have similar electronegativities, 1.84−2.05 for boron and 1.64−2.44 for silicon, depending on the estimation method. , Their respective covalent radii and first ionization enthalpies are 83 and 117 pm and 191.3 and 187.9 kcal/mol . Boron and silicon compounds in which each is covalently bound to carbon are common, as is electron- deficient bonding in many of their compounds. − Both elements are electrophilic, each able to expand its valence shell, boron generally to four from three and silicon to five or six from four. The resulting hypervalent species are a reflection of boron's electron deficiency (lacking an octet in its valence shell, empty 2p orbital), on the one hand, and of silicon's tendency to hypervalency caused either by accessible d orbital participation and/or σ* orbital participation and/or three-center molecular orbital involvement, on the other. − …”

Section: Introductionmentioning

confidence: 99%

Computational Studies of Electron Affinities, Acidities, and Bond Dissociation Energies of Boron-Containing Species: The CH₃(CH₂)_n_-1BH₂, CH₂F(CH₂)_n_-1BH₂, and CH₃(CH₂)_n_-1BHF Series

2007

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Computational studies of three series of boron-containing compounds, CH 3 (CH 2 ) n-1 BH 2 , CH 2 F(CH 2 ) n-1 BH 2 , and CH 3 (CH 2 ) n-1 BHF, have been carried out to probe the structural characteristics of the parent compounds and the radicals and anions derived by loss of their terminal C-H. The energies of these species yield electron affinities, acidities, and bond dissociation energies that are explained in terms of the structural characteristics, which vary with the value of n. One-carbon species are considered in terms of hyperconjugative effects. The radical species with n > 1 reveal important structures with strong tendencies for termini to interact. Carbon 2p radicals and empty 2p boron centers interact to give a cyclic radical species for BH 2 CH 2 CH 2 and BH 2 CH 2 CHF and bent radicals with short distances between the termini for larger values of n. The bent and zigzag BH 2 (CH 2 ) n-1 CH 2 radicals for n g 3 are quite close in energy. All anions with n g 2 are cyclic and considerably lower in energy than zigzag species. Single-point energies of parent, radical, and anionic species allow the determination of electron affinities (EA), acidities (∆H acid ), and bond dissociation energies (BDE). The EAs have a noticeable break between n ) 3 and 4, a consequence of the strain energy of the n ) 2 and 3 anions. The ∆H acid values exhibit trends also related to the strained nature of the n ) 2 and 3 anions. The values of the terminal C-H BDEs are typical of C-H bonds with the exception of the CF-substituted series, where the somewhat smaller values indicate the C-H bond-weakening effect of fluorine substitution.

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Theoretical Aspects of Compounds ContainingSi,Ge,SnandPb

Abstract: For Abstract see ChemInform Abstract in Full Text.

Cited by 4 publications

References 624 publications

Silicene is a phantom material

Silicene is a phantom material

Structure and Reactions of an Isolable Ge=Si Doubly Bonded Compound, Tetra(t-butyldimethylsilyl)germasilene

Computational Studies of Electron Affinities, Acidities, and Bond Dissociation Energies of Boron-Containing Species: The CH₃(CH₂)_n_-1BH₂, CH₂F(CH₂)_n_-1BH₂, and CH₃(CH₂)_n_-1BHF Series

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Theoretical Aspects of Compounds ContainingSi,Ge,SnandPb

Abstract: For Abstract see ChemInform Abstract in Full Text.

Cited by 4 publications

References 624 publications

Silicene is a phantom material

Silicene is a phantom material

Structure and Reactions of an Isolable Ge=Si Doubly Bonded Compound, Tetra(t-butyldimethylsilyl)germasilene

Computational Studies of Electron Affinities, Acidities, and Bond Dissociation Energies of Boron-Containing Species: The CH3(CH2)n-1BH2, CH2F(CH2)n-1BH2, and CH3(CH2)n-1BHF Series

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Computational Studies of Electron Affinities, Acidities, and Bond Dissociation Energies of Boron-Containing Species: The CH₃(CH₂)_n_-1BH₂, CH₂F(CH₂)_n_-1BH₂, and CH₃(CH₂)_n_-1BHF Series