Tris(2,4-pentanedionato)vanadium-catalysed cyclotrimerization and polymerization of 4-(N,N-dimethylamino)phenylethyne: X-ray structure of 1,2,4-tris[4-(N,N-dimethylamino)phenyl]benzene

Tris(pentane-2,4-dionato)vanadium-catalysed polymerization of 4-(N,N-dimethylamino)phenylethyne gave a polyene with pi-conjugated donor substituents. Similarly, cyclotrimerization of the acetylene derivative gave a mixture of 1,2,4- and 1,3,5-tris[4-(N,N-dimethylamino)phenyl]benzene in variable yield, depending on the reaction conditions employed. The molecular structure of the main 1,2,4- isomer was determined by X-ray diffraction methods.