An Exploration of the Hydrogen Bond Donor Ability of Ammonia

Ammonia is an important molecule due to its wide use in the fertiliser industry. It is also used in aminolysis reactions. Theoretical studies of the reaction mechanism predict that in reactive complexes and transition states, ammonia acts as a hydrogen bond donor forming N-H center dot center dot center dot O hydrogen bond. Experimental reports of N-H center dot center dot center dot O hydrogen bond, where ammonia acts as a hydrogen bond donor are scarce. Herein, the hydrogen bond donor ability of ammonia is investigated with three chalcogen atoms i. e. O, S, and Se using matrix isolation infrared spectroscopy and electronic structure calculations. In addition, the chalcogen bond acceptor ability of ammonia has also been investigated. The hydrogen bond acceptor molecules used here are O(CH3)(2), S(CH3)(2), and Se(CH3)(2). The formation of the 1 : 1 complex has been monitored in the N-H symmetric and anti-symmetric stretching modes of ammonia. The nature of the complex has been delineated using Atoms in Molecules analysis, Natural Bond Orbital analysis, and Energy Decomposition Analysis. This work presents the first comparison of the hydrogen bond donor ability of ammonia with O, S, and Se.

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In this study, the hydrogen bond donor ability of ammonia with O, S, and Se was investigated using matrix isolation infrared spectroscopy and electronic structure calculations. The formation of 1:1 complexes was monitored through the N-H symmetric and anti-symmetric stretching modes of ammonia. The nature of the complexes was analyzed using Atoms in Molecules analysis, Natural Bond Orbital analysis, and Energy Decomposition Analysis. This work provides the first comparison of the hydrogen bond donor ability of ammonia with O, S, and Se.