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Full-Text Articles in Physical Sciences and Mathematics
Coordination Of Anions By Noncovalently Bonded Σ-Hole Ligands, Steve Scheiner, Mariusz Michalczyk, Wiktor Zierkiewicz
Coordination Of Anions By Noncovalently Bonded Σ-Hole Ligands, Steve Scheiner, Mariusz Michalczyk, Wiktor Zierkiewicz
Chemistry and Biochemistry Faculty Publications
Research on σ-hole interactions that include halogen, chalcogen, pnicogen, and tetrel bonding has been accelerating in recent years. These cousins of the H-bond have many similar properties, including geometric preferences and energetics. Most of the work to date has focused on neutral complexes, with less known about these bonds to anions. This review summarizes the current state of knowledge about the complexes of anions with ligands that engage in these sorts of noncovalent bonds. Of particular interest are comparisons with H-bonds, and how the geometry of the fully coordinated complex varies as the number of surrounding ligands increases. A specific …
The Hydrogen Bond: A Hundred Years And Counting, Steve Scheiner
The Hydrogen Bond: A Hundred Years And Counting, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Since its original inception, a great deal has been learned about the nature, properties, and applications of the H-bond. This review summarizes some of the unexpected paths that inquiry into this phenomenon has taken researchers. The transfer of the bridging proton from one molecule to another can occur not only in the ground electronic state, but in various excited states as well. Study of the latter process has developed insights into the relationships between the nature of the state, the strength of the H-bond, and the height of the transfer barrier. The enormous broadening of the range of atoms that …
Comparison Of Halogen With Proton Transfer. Symmetric And Asymmetric Systems, Jia Lu, Steve Scheiner
Comparison Of Halogen With Proton Transfer. Symmetric And Asymmetric Systems, Jia Lu, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
The transfer of the halogen atom X within (A⸳⸳X⸳⸳A)+ systems was calculated for A = NH3, OH2, and CH3, and where X=Cl, Br, and I. These potentials are similar to those computed for equivalent proton transfers. Each contains a single symmetric well for short R(A⸳⸳A) distances. As R is stretched a second minimum appears, separated from the first by a transfer barrier E† which climbs quickly as R is elongated. The central X prefers association with the N in asymmetric systems (H3NX⸳⸳OH2)+, but a second (H3N⸳⸳XOH2)+ minimum, albeit less stable than the first, can appear if R(N⸳⸳O) is stretched.