Synthesis and Solid-State Polymerization of 5-(Pyren-1-yl)penta-2,4-diyn-1-ol Derivatives with an N-Phenylurethane or N-Benzylurethane Group

Abstract

A series of 5-(pyren-1-yl)penta-2,4-diyn-1-yl N-phenylcarbamates and N-benzylcarbamates were synthesized. Phenyl groups in the N-phenyl and N-benzyl moieties were unsubstituted (H-0 and H-1, respectively) and 3,4,5-trialkoxy substituted (C m O-0 and C m O-1, respectively), in which the alkyl groups introduced were methyl (m = 1), octyl (m = 8), dodecyl (m = 12), and hexadecyl (m = 16) groups. Upon UV irradiation, a regular 1,4-addition polymerization to form polydiacetylene was confirmed for H-0, H-1, C 8 O-1, C 12 O-1, and C 16 O-1. For C 1 O-0 and C 1 O-1, the crystal structures were solved, and the reasons the regular polymerization did not occur were clarified. From the powder X-ray diffraction study, crystallinities of C m O-1 were found to be lower than those of C m O-0, although C m O-1 regularly polymerized. This indicates that the total crystallinity is not directly related to local ordering around one-dimensional arrays for the polymerization direction. Polymerized C m O-1 species were soluble in chloroform. Their processability enabled us to fabricate cast films of polydiacetylene as well as the monomer. The conductivities of C 12 O-1 and the polymer (PC 12 O-1) were evaluated in the pristine and iodine-doped states and in the charge-transfer-complexed states with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane. A conductivity of 1.2 × 10 −2 S m −1 for iodine-doped PC 12 O-1 was achieved. In this case, pyrene moieties seemed to play an important role in realizing the appropriate electron transfer from pyrene moieties to iodine molecules and effective π conjugation between the pyrene moieties and the PDA backbone promoting charge transport.

Topochemical Synthesis of Conducting Radical Polymers

“…Utilizing carbamate chemistry, − we coassembled hexa-2,4-diyne-1,6-diyl bis((2,2,6,6-tetramethylpiperidinyloxyl)carbamate) (di-TEMPO–DA) and hexa-2,4-diyne-1,6-diyl bis(phenylcarbamate) (diphenyl-DA) in various organic solvents, and this led to supramolecular gelation through the N–H–O hydrogen bonding of the carbamate groups. This type of gelation occurs through the formation of a one-dimensional assembly, which is oft-observed for hydrogen bonded mediated supramolecular gelation .…”