Matrix Isolation Infrared Spectroscopic and Density Functional Theory Study of the 1:1 Complex of Bromocyclohexane with NH₃: Evidence for a Weak C–H–N Hydrogen Bond

Abstract

The hydrogen-bonded bromocyclohexane-ammonia complex has been isolated and characterized for the first time in argon matrices at 16 K. Coordination of the proton adjacent to the Br substituent on the cyclohexane ring to the amino nitrogen was evidenced by distinct blue shifts of bending modes involving the H-C 1 -Br unit. In particular, C-C 1 -Br, H-C 1 -Br, and C-C 1 -H bending modes produced blue shifts ranging from 2.8 to 12.2 cm À1 . Density Functional Theory (DFT) calculations at the B3LYP=6-31 þ G(d, p) level yield an essentially linear Br-C 1 -H-NH 3 hydrogen bond with a C-H-N distance of 2.412 Å and a hydrogen bond energy of 2.95 kcal=mol.

Polymer Soft-Landing Isolation of Acetylene on Polystyrene and Poly(vinylpyridine): A Novel Approach to Probing Hydrogen Bonding in Polymers

“…The work in our laboratory has focused on nonconventional C−H---N, C−H---O, and C−H---π hydrogen bonds in matrix isolated complexes such as those formed when bromocyclopropane, 3 cyclopentadiene, 4 bromocyclohexane, 5 and pentachlorocylcopropane 6 are codeposited with a variety of nitrogen and oxygen bases. More recently, in an attempt to find ways to use the matrix isolation laboratory to probe the building of nanostructures, we developed a technique in which we deposit our gaseous "guest" species diluted with "host" argon onto a cold surface that is coated with a polymer film at room temperature prior to the start of the experiment.…”