Crystalline inclusion compounds derived from derivatives of mandelic acid.Host synthesis, inclusion formation, and X-ray structures of a free host compound and of DMSO inclusion complexes in both racemic and optically resolved forms

New chiral host compounds based on mandelic acid derivatives having methyl (6a, b and 8a, b) or bromo substituents (7a, b) attached to the phenyl ring of mandelic acid and involving additional aromatic groups were synthesized . The inclusion properties of both the racemic and the optically resolved h ost species are reported, including solvent co-crystallization as well as c hiroselective and vapour sorptive inclusion. The structures of the free rac emic host compound 6b and of the DMSO inclusion compounds of optically reso lved and racemic 8 (8a and 8b, respectively) have been determined by X-ray analysis. Enantiomeric pairs of molecules in 6b form centro-symmetric dimer s by mutual hydrogen bonding of one hydroxyl group while the other is invol ved in O-H ... pi interactions. The guest molecules in the DMSO complexes o f 8a and 8b are bound via hydrogen bonds to two host molecules related by t ranslation along crystallographic axes. Parallels to previous hosts of this type are drawn.