title: Synthesis and properties of carborane-appended C(3)-symmetrical extended pi systems.
abstract: A series of C(3)-symmetric pi-conjugated compounds containing three to six o-carborane clusters have been synthesized by employing palladium-catalyzed Suzuki coupling reactions and palladium-catalyzed acetylation reactions, followed by silicon tetrachloride mediated trimerization reactions. Carborane-containing extended trimers were found to emit blue light. Incorporation of o-carborane clusters into extended pi-conjugated systems led to 22-70% enhancement of their relative fluorescence quantum yields. Decapitation of o-carborane clusters made these extended trimers water soluble, and their aqueous solutions were also found to be fluorescent, but with a reduced fluorescence intensity. The carborane-appended pi-conjugated compounds are found to be extremely thermally stable, and for some of these compounds only 10% mass loss occurred at temperatures close to 500 degrees C. The DSC thermograms of smaller C(cage)-appended trimers indicate the occurrence of solid-solid phase transitions.
authors.affiliation: Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115-2862, USA.
authors.forename: Barada Prasanna
authors.initials: BP
authors.lastname: Dash
authors.forename: Rashmirekha
authors.initials: R
authors.lastname: Satapathy
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Gaillard
authors.forename: John A
authors.initials: JA
authors.lastname: Maguire
authors.forename: Narayan S
authors.initials: NS
authors.lastname: Hosmane