Mechanochemical synthesis and crystal structure of a 1: 2 co-crystal of 1,3,6,8-tetraazatricyclo[4.3.1.13,8] undecane (TATU) and 4-chloro-3,5-dimethylphenol

Solvent-free treatment of 1,3,6,8-tetraazatricyclo[4.3.1.1 (3,8)] undecano (TATU) with 4-chloro-3,5-dimethylphenol led to the formation of the title co-crystal, C7H14N4 center dot 2C(8)H(9)ClO. The asymmetric unit contains one aminal cage molecule and two phenol molecules linked via two O-H center dot center dot center dot N hydrogen bonds. In the aminal cage, the N-CH2-CH2-N unit is slightly distorted from a syn periplanar geometry. Aromatic pi-pi stacking between the benzene rings from two different neighbouring phenol molecules [centroid-centroid distance = 4.0570 (11) angstrom] consolidates the crystal packing.