Weak hydrogen bonding. Part 3. A benzyl group accepting equally strong hydrogen bonds from O–H and C–H donors: 5-ethynyl-5H-dibenzo[a,d]cyclohepten-5-ol

Abstract

In the crystal structure of the title compound, one of the benzyl groups accepts hydrogen bonds from a hydroxy and an ethynyl group, one to each face of the ring. For both hydrogen bonds, energies around –1.3 kcal mol^–1 have been calculated. The bond donated by the hydroxy group has unusual geometry and is directed almost linearly at a C atom with H C = 2.36 Å.