title: Optical effects of S-oxidation and M(n+) binding in meso-thienyl dipyrrin systems and of stepwise bromination of 4,4-difluoro-8-(2,5-dibromo-3-thienyl)-4-bora-3a,4a-diaza-s-indacene.
abstract: We report 16 novel species and 8 molecular structures in studying how meso-thienyl-substituted dipyrrole oxidation, bromination, and metal ion binding impart optical changes, as monitored by UV-vis absorption/emission spectroscopy. Treatment of 4,4-difluoro-8-(3-benzothienyl)-4-bora-3a,4a-diaza-s-indacene (varphi(F) = 0.19) with m-CPBA gives selective S-dioxidation (varphi(F) = 0.006). Results of titrations of transition metal- and "scorpionate"-like dipyrrin species varied under room temperature treatment of m-CPBA. Ni-(thienyl-dipyrrin)(n) (n = 2) degraded significantly in the presence of m-CPBA, whereas related species (M = Cu, Fe, Co; n = 2, 3) were inert. meso-Thienyl group properties were revealed through the use of 3,4,4-triphenyl-8-(thienyl)-4-bora-3a,4a-diaza-s-indacene; Cu(2+) addition resulted in smooth absorption decreases which were modeled to support 1:1 substrate:M(2+) binding; for Hg(2+) 1:2 substrate:M(2+) binding was found. Treatment of 4,4-difluoro-8-(2,5-dibromo-3-thienyl)-4-bora-3a,4a-diaza-s-indacene with Br(2) gave red-shifted UV-vis absorption band features that grow with increasing dipyrrin bromination. Structures of the di- and tetra-substituted bromination products were obtained.
authors.affiliation: Molecular Logic Gate Laboratory, Department of Chemistry and School of Molecular Science -BK 21, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guseong-dong, Yuseong-gu, Daejeon, 305-701, Republic of Korea.
authors.forename: Shin Hei
authors.initials: SH
authors.lastname: Choi
authors.forename: Kibong
authors.initials: K
authors.lastname: Kim
authors.forename: June
authors.initials: J
authors.lastname: Jeon
authors.forename: Bhupal
authors.initials: B
authors.lastname: Meka
authors.forename: Daniela
authors.initials: D
authors.lastname: Bucella
authors.forename: Keliang
authors.initials: K
authors.lastname: Pang
authors.forename: Snehadrinarayan
authors.initials: S
authors.lastname: Khatua
authors.forename: Junseong
authors.initials: J
authors.lastname: Lee
authors.forename: David G
authors.initials: DG
authors.lastname: Churchill