The tri–μ–hydrido–bis[(η5–C5Me5)aluminum(III)] theoretical study, the assets of sandwiched M2H3 (M of 13th group elements) stability

Guermoune, Abdeladim; Lamsabhi, Al Mokhtar; Cherqaoui, Driss; Jarid, Abdellah; Anane, Hafid; Merino, Gabriel

doi:10.1007/s00894-009-0562-6

Cited by 2 publications

(1 citation statement)

References 41 publications

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“…[30][31][32][33][34][35][36] Among these complexes the so-called metallocenes are a paradigmatic example. 13,23,[25][26][27][37][38][39][40][41] Another aspect which renders the chemistry of cyclopentadiene particularly rich is that it can be functionalized by introducing different kinds of substituents containing main group elements to its C 5 perimeter. 8,[42][43][44][45][46][47][48][49][50] Depending on the range of electronegativities of the main element the bonding characteristics of the system and its structure may vary dramatically from an almost purely ionic interaction to a covalent one.…”

Section: Introductionmentioning

confidence: 99%

Stability trends and tautomerization of chalcocyclopentadienes. The role of aromaticity

et al. 2011

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International audienceThe stability trends and tautomerization processes within the family of chalcocyclopentadienes (CpXH, X = O, S, Se, Te) have been investigated through the use of high-level G3B3 and G2 ab initio, as well as B3LYP density functional theory calculations. All methods predict the 5-substituted derivative to be the least stable tautomer, with the only exception of the Te derivative. For X = O, Se the dominant forms are the 2- and the 1-substituted derivatives, respectively, whereas for S, an equal distribution of the two forms is predicted. The enhanced stability of the 5-substituted compound on going from O to Te is due to a parallel increase of the aromaticity of the system, through a charge donation from the C-X bond toward the five membered ring. Independently of the nature of the chalcogen heteroatom, the global minimum of the PES is the asymmetric keto structure 2-cyclopenten-1-one. Its enhanced stability with respect to the symmetric keto form 3-cyclopenten-1-one is due to a more favorable conjugation between the C[double bond, length as m-dash]X and the C[double bond, length as m-dash]C π-systems. This interaction steadily increases on going from O to Te. The barriers connecting the keto and the enolic forms are rather high, as those connecting the enolic forms among each other. Hence, an important conclusion is that, in the gas-phase, if the 5-substituted derivative is formed, it should be observable no matter the nature of the chalcogen heteroatom

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Section: Introductionmentioning

confidence: 99%

Stability trends and tautomerization of chalcocyclopentadienes. The role of aromaticity

et al. 2011

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Are cyclopentadienylberyllium, magnesium and calcium hydrides carbon or metal acids in the gas phase?

et al. 2010

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The structure and bonding of cyclopentadienylberyllium (CpBeH), magnesium (CpMgH), and calcium (CpCaH) hydrides as well as those of their deprotonated species have been investigated by means of B3LYP/6-311+G(3df,2p)//B3LYP/6-311+G(d,p) and B3LYP/6-311+G(3df,2p)//QCISD/6-311+G(d,p) density functional theory (DFT) calculations. The three compounds exhibit C(5v) equilibrium conformations in their ground states. For CpBeH the agreement between the calculated geometry and that determined by MW spectroscopy is excellent. CpMgH and CpCaH can be viewed almost as the result of the interaction between a C₅H₅⁻ anion and a XH(+) (X = Mg, Ca) cation. Conversely, for CpBeH the interaction between the C₅H₅ and the BeH subunits is significantly covalent. These compounds exhibit a significant aromaticity, usually named three-dimension aromaticity, in contrast with the unsubstituted cyclopentadiene compound. The CpBeH derivative behaves as a C acid in the gas phase and is less acidic than cyclopentadiene. More importantly, CpMgH and CpCaH, in spite of the X(+δ)H(-δ) polarity exhibited by the X-H bond in the neutral systems, are predicted to be metal acids in the gas phase. Also surprisingly, both the Mg and the Ca derivatives are stronger acids than the Be analogue, and only slightly weaker acids than cyclopentadiene. This somewhat unexpected result is the consequence of two concomitant facts: the lower dissociation energy of the X-H (X = Mg, Ca) bonds with respect to the C-H bonds, and the significantly high electron affinity of the C₅H₅X* (X = Mg, Ca) radicals.

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The tri–μ–hydrido–bis[(η5–C5Me5)aluminum(III)] theoretical study, the assets of sandwiched M2H3 (M of 13th group elements) stability

Cited by 2 publications

References 41 publications

Stability trends and tautomerization of chalcocyclopentadienes. The role of aromaticity

Stability trends and tautomerization of chalcocyclopentadienes. The role of aromaticity

Are cyclopentadienylberyllium, magnesium and calcium hydrides carbon or metal acids in the gas phase?

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