Optical Effects of <i>S</i>-Oxidation and M^<i>n</i>+ Binding in <i>meso</i>-Thienyl Dipyrrin Systems and of Stepwise Bromination of 4,4-Difluoro-8-(2,5-dibromo-3-thienyl)-4-bora-3<i>a</i>,4<i>a</i>-diaza-<i>s</i>-indacene

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 (ϕF = 0.19) with m-CPBA gives selective S-dioxidation (ϕF = 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; Cu2+ addition resulted in smooth absorption decreases which were modeled to support 1:1 substrate:M2+ binding; for Hg2+ 1:2 substrate:M2+ binding was found. Treatment of 4,4-difluoro-8-(2,5-dibromo-3-thienyl)-4-bora-3a,4a-diaza-s-indacene with Br2 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.本研究报道了16种全新物种与8种分子结构，旨在探究中位噻吩基取代二吡咯（meso-thienyl-substituted dipyrrole）的氧化、溴化及金属离子结合过程对光学特性的调控机制，相关变化通过紫外-可见吸收/发射光谱（UV−vis absorption/emission spectroscopy）进行监测。将4,4-二氟-8-(3-苯并噻吩基)-4-硼-3a,4a-二氮杂-s-茚省（4,4-difluoro-8-(3-benzothienyl)-4-bora-3a,4a-diaza-s-indacene，荧光量子产率ϕF = 0.19）与间氯过氧苯甲酸（m-CPBA）反应，可实现选择性S-双氧化，产物荧光量子产率ϕF = 0.006。室温下用间氯过氧苯甲酸处理过渡金属类与类蝎型二吡咯啉（dipyrrin）物种的滴定实验结果存在显著差异。当配位聚合度n=2时，Ni-(噻吩基二吡咯啉)配合物在间氯过氧苯甲酸存在下发生显著降解，而中心金属为Cu、Fe、Co且n=2、3的相关配合物则表现出化学惰性。通过3,4,4-三苯基-8-(噻吩基)-4-硼-3a,4a-二氮杂-s-茚省的实验体系，我们揭示了中位噻吩基的结构与反应特性；向该体系中加入Cu²+时，紫外-可见吸收强度平稳降低，通过建模分析证实底物与金属离子以1:1的化学计量比结合；而加入Hg²+时则观测到二者以1:2的化学计量比结合。将4,4-二氟-8-(2,5-二溴-3-噻吩基)-4-硼-3a,4a-二氮杂-s-茚省与溴单质反应，可得到红移的紫外-可见吸收带特征，且该特征随二吡咯啉的溴化程度加深而逐渐增强。本研究成功解析了二取代与四取代溴化产物的分子结构。