title: Palladium-catalyzed cycloisomerizations of diarylacetylenes: synthesis, structures, and physical properties of highly substituted naphthalenes and 8,8 a-dihydrocyclopenta[a]indenes.
abstract: Depending on the electronic properties of their substituents, the major products generated by palladium-catalyzed cycloisomerizations of diarylalkynes are either highly substituted 8,8a-dihydrocyclopenta[a]indenes 3 or naphthalenes 4. The structures of these compounds were verified by X-ray crystallographic analysis. Many functional groups tolerated the reaction conditions evaluated in this study. The isotope-labeled experiments indicated that added water has a critical role in forming both classes of compounds. The photophysical and electrochemical properties of cycloadducts 3 and their analogues were systematically studied and compared with computational predictions based on density functional theory. Dihydrocyclopenta[a]indenes 3 in either solid or liquid form display strong luminescence, whereas cyclopenta[a]indene 11 j is practically nonfluorescent. The functional groups directly attached to the backbone of compound 3 significantly influenced physical properties. The steric effect arising from the aryl substituents caused different luminescence phenomena, including aggregation-induced and -enhanced emission.
authors.affiliation: Department of Chemistry, National Cheng Kung University, No. 1 Ta-Hsueh Rd., 70101 Tainan, Taiwan.
authors.forename: Tsun-Cheng
authors.initials: TC
authors.lastname: Wu
authors.forename: Chia-Cheng
authors.initials: CC
authors.lastname: Tai
authors.forename: Hsin-Chieh
authors.initials: HC
authors.lastname: Tiao
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Chang
authors.forename: Chia-Chun
authors.initials: CC
authors.lastname: Liu
authors.forename: Ching-Hsiu
authors.initials: CH
authors.lastname: Li
authors.forename: Cheng-Hao
authors.initials: CH
authors.lastname: Huang
authors.forename: Ming-Yu
authors.initials: MY
authors.lastname: Kuo
authors.forename: Yao-Ting
authors.initials: YT
authors.lastname: Wu