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

A new supramolecular complex (I) between the tetraphosphonate cavitand Tiiii[C 3 H 7,CH 3,C 6 H 5 ] [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 C 11 H 16 NO + ·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 (C 11 H 16 NO)@Tiiii[C 3 H 7,CH 3,C 6 H 5 ]Cl·CH 3 OH or C 11 H 16 NO + ·Cl - ·C 68 H 68 O 12 P 4 ·CH 3 OH, crystallizes in the monoclinic space group P2 1 /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.