Tuning Topochemical Polymerization of Diacetylenes: A Joint Synthetic, Structural, Photophysical, and Theoretical Study of a Series of Analogues of a Known Reactive Monomer, 1,6-Bis(diphenylamino)-2,4-hexadiyne (THD)

Several analogues of 1,6-bis(diphenylamino)-2,4-hexadiyne (THD) have been prepared and their thermal and photochemical solid-state polymerization reactivity assessed. The compounds involved in this investigation are 1,6-bis(dibenzylamino)-2,4-hexadiyne (1), 1,6-bis(di-p-tolylamino)-2,4-hexadiyne (2), 1,6-bis(dipentafluorophenylamino)-2,4-hexadiyne (3), 1,6-bis((N-pentafluorophenyl)phenylamino)-2,4-hexadiyne (4), 1,12-bis(diphenylamino)-5,7-dodecadiyne (5), and 1,10-bis(diphenylamino)-4,6-decadiyne (6). Compound 6 is the only diacetylene that showed measurable polymerization reactivity, and this behavior was rationalized on the basis of X-ray crystallographic results. Yet, diyne 6 is much less reactive than THD, so the preparation of weakly polymerized single crystals of 6 proved to be possible and the study of the spectroscopic properties of “diluted” poly-6 chains feasible. Unlike poly-THD, poly-6 is quite soluble in organic solvents such as chloroform and THF, so determination by SEC of the molecular we...