- Turkish Journal of Chemistry
- Vol: 42 Issue: 4
- New triplet silylenes M–Si–M′–X along with some unusual cyclic forms (M = Li, Na, and K; M′ = Be, Mg...
New triplet silylenes M–Si–M′–X along with some unusual cyclic forms (M = Li, Na, and K; M′ = Be, Mg, and Ca; X = F, Cl, and Br)
Authors : Samaneh Ashenagar, Mohamad Zaman Kassaee
Pages : 974-987
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Publication Date : 9999-12-31
Article Type : Makaleler
Abstract :Comparison of 54 M-Si--M ′ ′ -X species is carried out using quantum mechanical ab initio and DFT computations at B3LYP/6-311 + + ++ G**, QCISD(T)/6-311 + + ++ G**, and CCSD(T)/6-311 + + ++ G** levels of theory (M = Li, Na, K; M ′ ′ = Be, Mg, Ca, and X = F, Cl, Br). All triplet species with M = K appear more linear than their corresponding ones with Li and Na. The electronegativity reactivity descriptor for each halogen (X = F, Cl, Br) is used as a tool to evaluate the interrelated properties of these silylenes. Stability, assumed as singlet-triplet energy difference ( Δ E S − T ) ΔES−T) for each series depends on the substituent's electropositivity, analyzed by applying appropriate isodesmic reactions. Stability of triplet M--Si-M ′ ′ -X silylenes increases as functions of electropositivity of α α -substituents and of β β -substituents. The purpose of the present work was therefore to assess the influence of different di-alkaline metals with different β β -substituents on the singlet--triplet energy gaps.Keywords : Triplet silylene, electropositivity, energy gaps, and substituent effects, multiplicity