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.