Bonding Rearrangements of Hydrogen Bonded Complexes involving Alkynes

Authors

E. S. Kryachko
Steve Scheiner, Utah State UniversityFollow

Document Type

Article

Journal/Book Title

Journal of Physical Chemistry A

Publication Date

2008

Publisher

American Chemical Society

Volume

112

Issue

9

First Page

1940

Last Page

1945

Abstract

Molecules containing a C−C triple bond, such as HCCH, FCCF, and the CCH radical, are allowed to interact with a partner molecule of H₂O, NH₃, or HF. Quantum chemical calculations show that these CCH···X H-bonded complexes are bound by up to 4 kcal·mol^-1. More importantly, they can rearrange in such a way that the partner molecule adds to the triple bond so as to form a double CC bond. Whereas this process is strongly exoergic, there is a high-energy barrier to this rearrangement process. On the other hand, when a second water molecule is added to the complex, it can shuttle protons from the donor part of the complex to the acceptor, and thereby greatly reduce the rearrangement energy barrier. In the case of CCH + 2H₂O, this barrier is computed to be less than 4 kcal·mol^-1.

Comments

Originally published by American Chemical Society in the Journal of Physical Chemistry.

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Recommended Citation

Bonding Rearrangements of Hydrogen Bonded Complexes involving Alkynes E. S. Kryachko, S. Scheiner J. Phys. Chem. A 2008 112 1940-1945