Simultaneous electrophile–nucleophile Cl⋯π interactions stabilizing solid state inclusions: a new tool for supramolecular crystal engineering

Abstract

The crystalline inclusions of the host compound trans-11,12-bis[bis(p-chlorophenyl)hydroxymethyl]-9,10-ethanoanthracene, with guests such as pentan-2-ol[1·pentan-2-ol(1:1), 1a], 1,4-dioxane [1·1,4-dioxane (2:5), 1b] and o-xylene [1·o-xylene (1:2), 1c] were shown by X-ray analysis to have host matrices mainly determined by directional ‘electrophile–nucleophile pairing’ interactions, involving a chloro substituent and the adjacent aryl π electrons of a neighbouring molecule. The observed shorter Cl⋯centroid distances in 1a–c are between 3.33 and 3.75 Å. On the other hand, the versatility of host–guest interactions due to the different proton donor–acceptor abilities and polarities of the guests yielded various packing relations with different symmetries and conformations of the host hydroxy functions. Although compounds 1a and 1b contain H-bonded 1·pentanol and 1·dioxane aggregates, respectively, the realized packing arrangements seem to be a compromise between close packing on the one hand and hydrogen bonding on the other. Compound 1c is a lattice-type inclusion in which the o-xylene guests are trapped in tunnels formed by the bulky host molecules.