SYNTHESIS AND X-RAY STRUCTURAL INVESTIGATION OF 1,3,5-TRIS[4-(2-PROPYNYLOXY)PHENYL]BENZENE

Synthesis and X-ray structural investigation of 1,3,5-tris[4-(2-propyn yloxy)phenyl]benzene (1) were carried out. Compound 1 is a trifunction al monomer for the synthesis of cross-linked polymers and a model of a section of polymeric network of this kind. In a crystal, the molecule of 1 is located on the threefold symmetry axis and has a propeller-li ke conformation (the dihedral angle between the central and peripheral benzene rings is approximately 35-degrees). An essential feature of t he crystal structure of 1 is the proximity of the ethynyl groups of th e neighboring molecules, which may be favorable to cyclotrimerization in the crystal. The spatial prerequisite to this process is the simult aneous rotation of the neighboring molecules 1 about their symmetry ax es by approximately 10-degrees. The displacements of the atoms in the reacting groups should amount to approximately 1.6-1.8 angstrom.