Hydrogen-bonded complexes of bromocyclopropane with the strong bases ammonia and trimethylamine have 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 cyclopropane ring to the nitrogen of the base was evidenced by distinct blue shifts of the C−H(Br) bending modes in the infrared spectrum. These shifts (∼12 cm-1 for the in-plane bend and ∼6 cm-1 for the out-of-plane bend) are much smaller than those observed for alkenes and alkynes, suggesting a distinct but extremely weak interaction. Ab initio calculations yield an essentially linear BrC−H···NH3 hydrogen bond with a C−H···N distance of 2.301 Å and a hydrogen bond energy of 2.35 kcal/mol, thus supporting that this hydrogen bond is one of the weakest observed thus far in a matrix. This study represents the first example of a (substituted) cyclopropane acting as a proton donor and only the second example of an alkane taking part in a C−H···N hydrogen bond.

The large number of biology majors and prehealth students enrolled in Organic Chemistry makes it desirable to have laboratories that involve biologically interesting molecules. Although many laboratory manuals contain sections on carbohydrate chemistry, the experiments are typically limited to esterification or hydrolysis reactions. A recent publication (Toshima, K.; Ishizuka, T.; Matsuo, G.; Nakata, M. Synlett. 1995, 306. ) on the glycosidation of glycals offered a different possibility.

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