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Full-Text Articles in Physical Sciences and Mathematics
Comparison Of Bifurcated Halogen With Hydrogen Bonds, Steve Scheiner
Comparison Of Bifurcated Halogen With Hydrogen Bonds, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Bifurcated halogen bonds are constructed with FBr and FI as Lewis acids, paired with NH3 and NCH bases. The first type considered places two bases together with a single acid, while the reverse case of two acids sharing a single base constitutes the second type. These bifurcated systems are compared with the analogous H-bonds wherein FH serves as the acid. In most cases, a bifurcated system is energetically inferior to a single linear bond. There is a larger energetic cost to forcing the single σ-hole of an acid to interact with a pair of bases, than the other way …
Comparison Of Ch∙∙O, Sh∙∙O, Chalcogen, And Tetrel Bonds Formed By Neutral And Cationic Sulfur-Containing Compounds, Steve Scheiner
Comparison Of Ch∙∙O, Sh∙∙O, Chalcogen, And Tetrel Bonds Formed By Neutral And Cationic Sulfur-Containing Compounds, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
The ability of neutral and charged S-compounds to form different sorts of noncovalent bonds is examined by ab initio calculations. Neutrals are represented by CH3SH and fluoro substituted FSCH3; cations are (CH3)3S+, CH3SH2+, and FHSCH3+. Each is paired with N-methylacetamide (NMA) whose O atom serves as common electron donor. Charged species engage in much stronger noncovalent bonds than do the neutral molecules, by as much as an order of magnitude. The strongest noncovalent bond for any system is a O∙∙SF chalcogen bond wherein the O lies directly opposite a S-F covalent bond, amounting to as much as 39 kcal/mol. Second …