Crystal structure of a host–guest complex between mephedrone hydrochloride and a tetraphosphonate cavitand

Abstract

A new supramolecular complex (I) between the tetraphosphonate cavitand Tiiii[C3H7,CH3,C6H5] [systematic name: 2,8,14,20-tetrapropyl-5,11,17,23-tetramethyl-6,10:12,16:18,22:24,4-tetrakis(phenylphosphonato-O,O′)resorcin[4]arene] and mephedrone hydrochoride {C11H16NO+·Cl−; systematic name: methyl[1-(4-methylphenyl)-1-oxopropan-2-yl]azanium chloride} has been obtained and characterized both in solution and in the solid state. The complex of general formula (C11H16NO)@Tiiii[C3H7,CH3,C6H5]Cl·CH3OH or C11H16NO+·Cl−·C68H68O12P4·CH3OH, crystallizes in the monoclinic space group P21/c with one lattice methanol molecule per cavitand, disordered over two positions with occupancy factors of 0.665 (6) and 0.335 (6). The mephedrone guest interacts with the P=O groups at the upper rim of the cavitand through two charge-assisted N—H...O hydrogen bonds, while the methyl group directly bound to the amino moiety is stabilized inside the π basic cavity via cation...π interactions. The chloride counter-anion is located between the alkyl legs of the cavitand, forming C—H...Cl interactions with the aromatic and methylenic H atoms of the lower rim. The chloride anion is also responsible for the formation of a supramolecular chain along the b-axis direction through C—H...Cl interactions involving the phenyl substituent of one phosphonate group. C—H...O and C—H...π interactions between the guest and adjacent cavitands contribute to the formation of the crystal structure.