Synthesis and Properties of an Overcrowded Silabenzene Stable at Ambient Temperature

Wakita, Keiji; Tokitoh, Norihiro; Okazaki, Renji; Nagase, Shigeru

doi:10.1002/(sici)1521-3773(20000204)39:3<634::aid-anie634>3.3.co;2-r

Cited by 52 publications

(95 citation statements)

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“…Gel permeation liquid chromatography (GPLC) was performed (LC-908 and LC-918 Systems; Japan Analytical Industry Co., Ltd.) with JAIGEL 1H and 2H columns (eluent: CHCl 3 ). 1-Silacyclohexadienes 3-5 were prepared according to the reported procedures [15]. Scaling up of the reactions described in this text might be possible, even though all reactions were performed at milligram scale.…”

Section: General Experimental Detailssupporting

confidence: 84%

Novel silacyclohexadienyl chromium and iron complexes bearing a bulky substituent on the central silicon atom

Tanabe

Mizuhata

Tokitoh

2010

Pure and Applied Chemistry

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Novel hydrido(silacyclohexadienyl)chromium complexes bearing a bulky substituent, Tbt (2,4,6-tris[bis(trimethylsilyl)methyl]phenyl), were synthesized using formal insertion reactions of Cr(0) into C-H or Si-H bond. When the reactions of 1-silacyclohexa-2,4-dienes bearing a hydroxy or chloro group on the silicon atom with [Cr(CH 3 CN) 3 (CO) 3 ] were performed, the corresponding hydrido(1-silacyclohexa-2,4-dienyl) complexes were obtained as the sole product. A similar reaction of a hydrosilane having a similar skeleton with [Cr(CH 3 CN) 3 (CO) 3 ] gave an unprecedented type of silacyclohexadienyl complex, hydrido(1-silacyclohexa-1,3-dienyl)chromium bearing a three-center bonding interaction among the silicon, hydrogen, and chromium atoms. These are the first syntheses of silacyclohexadienyl complexes by the formal insertion reaction toward the corresponding silacyclohexadienes. Furthermore, the isolation of the silacyclohexadienyl anion was achieved; it was applied to synthesis of the corresponding sandwich-type iron complex. Structures of the newly obtained complexes were revealed based on their NMR and IR spectroscopic data and X-ray diffraction study.

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Section: General Experimental Detailssupporting

confidence: 84%

Novel silacyclohexadienyl chromium and iron complexes bearing a bulky substituent on the central silicon atom

Tanabe

Mizuhata

Tokitoh

2010

Pure and Applied Chemistry

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“…53,54 This causes significant problems for their experimental investigation. However, spectral data and structural analysis 55,56 suggest significant aromatic character of the cyclic conjugated system in these compounds in agreement with early theoretical studies. 57 Later calculations of NICS, HOMA and ASE indices demonstrated 58,59 that sila-and germabenzenes are highly aromatic.…”

Section: Distinguish I)mentioning

confidence: 99%

Aromaticity in heterocyclic analogues of benzene: comprehensive analysis of structural aspects, electron delocalization and magnetic characteristics

Omelchenko

Шишкин

Gorb

et al. 2011

Phys. Chem. Chem. Phys.

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The degree of aromaticity of six-membered monoheterocycles with IV -VI group heteroatoms (C 6 H 5 X, where X=SiH, GeH, N, P, As, O + , S + , Se + ) was analyzed using the results of ab initio calculations at the MP2/cc-pvtz level. Values of common aromaticity indices including those based on electronic delocalization properties, structural-dynamic features and magnetic properties all indicate high aromaticity of all considered heterocycles.A decrease in aromaticity is observed with increasing atomic number of the heteroatom, except in the case of the pyrylium cation. However, not all types of indices or even different indices within the same type correlate well among each other. Ring currents have been obtained at the HF/cc-pvdz level using the ipsocentric formulation. Ring current maps indicate that in the case of cationic heterocycles the ring current persists in all molecules under consideration. The different conclusions reached depending on the type of index used, are a manifestation of the fact that when not dealing with hydrocarbons, aromaticity is illdefined. One should always express explicitly which property of the molecules is considered to establish a degree of "aromaticity".

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“…Subsequently, silicene has also been synthesized over zirconium diboride and iridium surfaces . Although silicon prefers to be in an sp 3 hybridized state, there are several examples of silicon–silicon multiple bonds in the literature . As reported by Tamao et al, SiSi units has a smaller energy gap between HOMO and LUMO compared to their carbon counterparts and therefore can be employed for different applications in electronic devices …”

Section: Introductionmentioning

confidence: 99%

Analysis of pseudo jahn–teller distortion based on natural bond orbital theory: Case study for silicene

2019

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Ground state (GS) instability of nondegenerate molecules in high symmetric structures is understood through Pseudo Jahn–Teller mixing of the electronic states through the vibronic coupling. The general approach involves setting up of a Pseudo Jahn–Teller (PJT) problem wherein one or more symmetry allowed excited states couple to the GS to create vibrational instability along a normal mode. This faces two major complications namely (1) estimating the adiabatic potential energy surfaces for the excited states which are often difficult to describe in case the excited states have charge‐transfer or multi‐excitonic (ME) character and (2) finding out how many such excited states (all satisfying the symmetry requirements for vibronic coupling) of increasing energies need to be coupled with the GS for a particular PJT problem. An analogous alternative approach presented here for the well‐known case of symmetry breaking of planar (D6h) hexasilabenzene (Si6H6) to the buckled (D3d) structure involves identifying the second‐order donor–acceptor, hyperconjugative interactions (E2i → j) that stabilize the distorted structure. Following the recent work of Nori‐Shargh and Weinhold, one observes that the orbitals involved in the vibronic coupling between the S0/Sn states and those for the donor (filled)–acceptor (empty) interactions are identical. In fact, deletion of any particular pair of E2i → j interaction creates vibrational instability in the buckled structure and as a corollary, deleting it for the planar structure removes its instability. The one‐to‐one correlation between the natural bond orbital theory and PJT theory assists in an intuitive identification of the relevant (few) excited states from a manifold of computed ones that cause symmetry breaking by vibronic coupling. © 2019 Wiley Periodicals, Inc.

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Synthesis and Properties of an Overcrowded Silabenzene Stable at Ambient Temperature

Cited by 52 publications

References 0 publications

Novel silacyclohexadienyl chromium and iron complexes bearing a bulky substituent on the central silicon atom

Novel silacyclohexadienyl chromium and iron complexes bearing a bulky substituent on the central silicon atom

Aromaticity in heterocyclic analogues of benzene: comprehensive analysis of structural aspects, electron delocalization and magnetic characteristics

Analysis of pseudo jahn–teller distortion based on natural bond orbital theory: Case study for silicene

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