Crystalline inclusion compounds of hosts composed of anthracene, ethylene and crowded alcoholic building blocks

A series of new clathrate host molecules 1–3 (a, b) have been synthesized, which contain two bulky alcoholic groups attached via an acetylene connection element to different positions (1,5, 1,8 or 9,10) of a basic anthracene construction unit. Their clathrate formation properties with organic guests, including amines, dipolar aprotic and apolar compounds, are reported (78 examples of clathrates); these demonstrate a characteristic level of selectivity. The crystal structures of three selected clathrates, containing acetone or tetrahydrofuran as the guest, have been determined by X-ray diffraction. H-bonded 1∶2 host–guest associates are formed in these clathrates, where each of the host hydroxy groups binds to a guest oxygen, although the host–guest arrangements in the acetone and tetrahydrofuran complexes are different in orientation, being in endo- and exo-mode relative to the anthracene unit, respectively.