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-propynyloxy)phenyl]benzene (1) were carried out. Compound1 is a trifunctional 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 of1 is located on the threefold symmetry axis and has a propeller-like conformation (the dihedral angle between the central and peripheral benzene rings is ∼35°). An essential feature of the crystal structure of1 is the proximity of the ethynyl groups of the neighboring molecules, which may be favorable to cyclotrimerization in the crystal. The spatial prerequisite to this process is the simultaneous rotation of the neighboring molecules1 about their symmetry axes by ∼10°. The displacements of the atoms in the reacting groups should amount to ∼1.6–1.8 Å