Halogenated isomers of the interstellar C3H2: an ab initio comparative study

A quest for triplet silylenes XHSi3 at ab initio and DFT levels (X=H, F, Cl and Br)

“…This is in consistent with the other reports, on many related acyclic carbenic and silylenic systems, while it is in contrast to the results of the corresponding cyclic carbenic and/or silylenic systems [8,[29][30][31][32][33][34][35]. This discrepancy may be rationalized by considering the electronic structures and hybridizations of the corresponding bonds, attached to the divalent center.…”

“…Interestingly, the stability order of FHSi 3 silylenes appears quite different from the above stability trend of H 2 Si 3 , and is in clear contrast to analogues C 3 FH carbenes [29]. Moreover, with the most electronegative halogen, singlet species of 1 s-F and 3 s-F are more stable than their corresponding triplet states (1 t-F and 3 t-F , respectively).…”

“…Apparently, the aromatic character, the large size of Si atoms, and/or the longer Si-Si bonds reduce the strain in these cyclic structures [20]. This is in contrast to the analogous, highly energetic, cyclic triplet carbenic C 3 HX, and/or the silylenic C 2 HXSi species, where the originally adopted cyclic structures may even rupture during the optimizations [29,32]. Interestingly the minimum 1 s-H has a C 2v point group, while all the other cyclic species have merely a plane of symmetry with a C s point group (Figs.…”

“…Following up on our studies on divalent species of group 14 elements [3,[28][29][30][31][32][33][34], as well as the specific studies of Maier et al on the small and matrix isolable silylenes C 2 HXSi [35]; a quest is made for triplet silylenes XHSi 3 at ab initio and DFT levels (X = H, F, Cl and Br) (see Fig. 1).…”

Novel quintet and triplet (nitrenoethynyl)halomethylenes at theoretical levels

“…Hence, following our related studies [20][21][22][23][24][25], in this work, we are taking up (nitrenoethynyl)halomethylene, N-C:C-C-X, at theoretical levels (X = H, F, Cl, and Br). In spite of their anticipated instability and experimental inaccessibility, the significance of these species justifies our theoretical scrutiny.…”