Inter/Intramolecular Bonds in TH5+ (T = C/Si/Ge): H-2 as Tetrel Bond Acceptor and the Uniqueness of Carbon Bonds

Gnanasekar, Sharon Priya and Arunan, Elangannan (2019) Inter/Intramolecular Bonds in TH5+ (T = C/Si/Ge): H-2 as Tetrel Bond Acceptor and the Uniqueness of Carbon Bonds. In: JOURNAL OF PHYSICAL CHEMISTRY A, 123 (6). pp. 1168-1176.

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Abstract

Atoms in molecules (AIM), natural bond orbital (NBO), and normal coordinate analysis have been carried out at the global minimum structures of TH5+ (T = C/Si/Ge). All these analyses lead to a consistent structure for these three protonated TH4 molecules. The CH5+ has a structure with three short and two long C-H covalent bonds and no H-H bond. Hence, the popular characterization of protonated methane as a weakly bound CH3+ and H-2 is inconsistent with these results. However, SiH5+ and GeH5+ are both indeed a complex formed between TH3+ and H-2 stabilized by a tetrel bond, with the H-2 being the tetrel bond acceptor. The three-center-two-electron bond (3c-2e) in CH5+ has an open structure, which can be characterized as a V-type 3c-2e bond and that found in SiH5+ and GeH5+ is a T-type 3c-2e bond. This difference could be understood based on the typical C-H, Si-H, Ge-H, and H-H bond and the tetrel bond energies. This analysis explains the trend observed in proton affinity of TH4 which appears counterintuitive, GeH4 > SiH4 > CH4. Carbon is selective in forming a ``tetrel bond'' and when it does, it might be worthwhile to highlight it as a ``carbon bond''.

Item Type:	Journal Article
Publication:	JOURNAL OF PHYSICAL CHEMISTRY A
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copyright of this article belongs to AMER CHEMICAL SOC
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	26 Mar 2019 07:48
Last Modified:	26 Mar 2019 07:48
URI:	http://eprints.iisc.ac.in/id/eprint/61935

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