Synthesis, characterization and intermolecular interactions in crystals of two p-tert-butylthiacalix[4]arene diisocyanide and diamine derivatives

The synthesis, the spectral characterization and the crystal structure of 25,27-bis(2-isocyanoethoxy)-5,11,17,23-tetra-tert-butyl-26,28-dihydroxythiacalix[4]arene and of the reaction intermediate 25,27-bis(2-aminoethoxy)-5,11,17,23-tetra-tert-butyl-26,28-dihydroxythiacalix[4]arene are here described. The target diisonitrile compound crystallizes in the triclinic system with space group P-1 while the diamine intermediate is trigonal with space group R-3. In both structures, the thiacalix[4]arene units adopt a broadly similar pinched cone conformation, where two aromatic rings bearing an ethereal group are almost parallel while two phenolic rings lie near-vertically. In the supramolecular structure of both molecules, various intermolecular interactions involving C-H center dot center dot center dot O, C-H center dot center dot center dot C, C-H center dot center dot center dot pi and weak C-H center dot center dot center dot S interactions were found. Moreover, the Hirshfeld surface analysis of the target compound was made to further confirm the crystal packing driving forces. (C) 2016 Elsevier B.V. All rights reserved.