title: Calix[2]bispyrrolylarenes: new expanded calix[4]pyrroles for fluorometric sensing of anions via extended π-conjugation.
abstract: Two new expanded calix[4]pyrroles 3 and 4 were synthesized by '2 + 2' cyclocoupling of easily prepared diboryldipyrromethane 7 (by Ir-catalyzed CH-bond activation) with appropriate diiodoarenes using the Suzuki protocol. Owing to the unique design, both macrocycles exhibited extended π-conjugation and enhanced fluorescence. Upon complexation with anions (fluoride and acetate), receptor 3 displayed turn-on sensing of fluorescence, whereas 4 showed turn-off sensing.
authors.affiliation: School of Chemistry, University of Hyderabad, Hyderabad 500 046, India.
authors.forename: Brijesh
authors.initials: B
authors.lastname: Chandra
authors.forename: Sanjeev P
authors.initials: SP
authors.lastname: Mahanta
authors.forename: Narendra N
authors.initials: NN
authors.lastname: Pati
authors.forename: Sambath
authors.initials: S
authors.lastname: Baskaran
authors.forename: Ravi K
authors.initials: RK
authors.lastname: Kanaparthi
authors.forename: Chinnappan
authors.initials: C
authors.lastname: Sivasankar
authors.forename: Pradeepta K
authors.initials: PK
authors.lastname: Panda