HYBRIDE INTERACTIONS (STACKING PLUS H-BONDS) BETWEEN MOLECULES BEARING BENZYL GROUPS

In this paper, the crystal structure of the ne-5,6-dideoxy-alpha-D-rib o-hex-5-yno-1,4-furanose is presented. This is the first noticed examp le in which weak hydrogen bonds prevail over the pi-pi stacking intera ctions of the aromatic rings. As a result, the hybride interactions an formed by the pi-sigma stacking and the C-H...pi hydrogen bonds. The analysis of molecular packing of crystal structures collected in the C ambridge Crystallographic Database shows that hybride interactions occ ur in infinite columns of benzyl groups or in binary complexes of orga nic molecules. Semiempirical calculations suggest that the pi-sigma st acking interactions and the C-H...pi hydrogen bonds have a synergic ch aracter. Probably they are the key factor which stimulates the growth of crystals. (C) 1998 Elsevier Science B.V.