A Novel One-Step Nickel-Mediated Synthesis of C6Ar6 Conjugated Hydrocarbons, Highly Substituted and Overcrowded Fulvenes and 3,4-Dimethylenecyclobutenes

Abstract

Nickel-catalyzed cyclo-oligomerization of aryl-substituted 1,1-dibromoethylenes in the presence or absence of diarylacety-lenes produces 1,2,3,4,6,6-hexaarylfulvenes and/or 1,2-diaryl-3,4-bis(diarylmethylene)cyclobutenes in moderate yields, providing a new and simple method for C6Ar6 conjugated hydrocarbons, highly overcrowded systems.

Field Effect Studies on Rubrene and Impurities of Rubrene

“…Compound A, C 42 H 30 , has been reported to form by the reaction of diaryl 1,1-dibromoethylene with active metallic nickel, and we found traces of it in the commercial rubrene. The synthetic procedure used for the commercial rubrene is unknown to us and we cannot explain the origin of A, which appears to be an unlikely product of the older preparation method …”

Aggregation-induced and crystallization-enhanced emissions of 1,2-diphenyl-3,4-bis(diphenylmethylene)-1-cyclobutene

“…No change is detected either after it has been put on a shelf under normal laboratory lighting for 1 month or exposed to the irradiation of a UV light of 365 nm for 4 h. A literature search reveals that the molecule can be synthesized from the reaction of diphenyl-1,1-dibromoethylene with active metallic nickel. 8 Field effect activity of the dye has been reported 9 but its luminescence behaviour is virtually unknown. 7 To confirm the AIE nature of HPDMCb, we measured its PL spectra.…”

Diindeno[2,1-b:2′,1′-h]biphenylenes: Syntheses, Structural Analyses, and Properties

“…The cyclobutene-based DFAs diindeno­[2,1- b :2′,1′- h ]­biphenylenes 1 – 4 contain p -QDM moieties, which suffer from a strong geometric perturbation, may have interesting structural features and properties. Although the structures of CS- 1 – 4 contain bis­(methylene)-1-cyclobutenyl (BMC) fragments, such as 1,2-diphenyl-3,4-bis­(diphenylmethylene)-1-cyclobutene, the structural characteristics of biphenylene with the predominant resonance form A could be a driving force for converting them to their singlet biradical forms OS- 1 – 4 . Therefore, the chemistry and properties of these new compounds are investigated herein.…”