Binary Complexes of Ammonia with Phenylacetylenes: A Combined Experimental and Computational Approach to Explore Multiple Minima on Intermolecular Potentials. Issue 4 (20th December 2012)

• Record Type: Journal Article
• Authors: Dey, Arghya; Mondal, Sohidul Islam; Patwari, G. Naresh
• Is Part Of: Chemphyschem. Volume 14:Issue 4(2013)
• Page Start: 746
• Page End: 753
• Publication Date: 2012-12-20
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201200797
• Languages: English
• ISSNs: 1439-4235

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The hydrogen‐bonded complexes of phenylacetylene, 4‐fluorophenylacetylene, 2‐fluorophenylacetylene, and 2, 6‐difluorophenylacetylene with ammonia are investigated using IR–UV double resonance spectroscopy in combination with high‐level ab initio calculations at the CCSD(T)/CBS level of theory. The CH⋅⋅⋅N hydrogen‐bonded complex, which involves an interaction of ammonia with the acetylenic CH group is the global minimum and is observed in all four cases investigated. In addition, phenylacetylene and 4‐fluorophenylacetylene form a quasi‐planar cyclic complexes with ammonia incorporating NH⋅⋅⋅π and CH⋅⋅⋅N hydrogen bonds, wherein the π‐electron density of the acetylenic CC bond acts as an acceptor to the NH group of ammonia. A third ammonia complex is observed for 4‐fluorophenylacetylene in which ammonia interacts with the fluorine atom once again, leading to the formation of a quasi‐planar cyclic complex. The substitution of the fluorine atom on the phenyl ring of phenylacetylene modulates the intermolecular potentials, which are dependent on the position of the substitution.</p> </abstract>