Control of On鈥揙ff or Off鈥揙n Fluorescent and Optical [Cu2+] and [Hg2+] Responses via Formal Me/H Substitution in Fully Characterized Thienyl 鈥淪corpionate鈥?like BODIPY Systems

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• 作者：Kibong Kim ; Shin Hei Choi ; June Jeon ; Hyosun Lee ; Jung Oh Huh ; Jaeduk Yoo ; Jong Taek Kim ; Chang-Hee Lee ; Yoon Sup Lee ; David G. Churchill
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：June 20, 2011
• 年：2011
• 卷：50
• 期：12
• 页码：5351-5360
• 全文大小：1171K
• 年卷期：v.50,no.12(June 20, 2011)
• ISSN：1520-510X

文摘

One 8-phenyl and two 8-mesityl-substituted 鈥渟corpionate鈥?like BODIPY-type species of the formula [3,4,4-tris(5-R-(2-thienyl))-8-(2,4,6-R鈥?/i>-phenyl)-4-bora-3a,4a-diaza-s-indacene (R = H, R鈥?= H, 3a; R, = H, R鈥?= Me, 2a; R, = Me, R鈥?= Me, 2b)] have been synthesized and fully characterized. Importantly, differences in their solution (MeCN) optical Cu²⁺ and Hg²⁺ probing capacity via SSS-chelation were investigated. Compounds 2a鈥?b>3a were prepared from the requisite 8-substituted BODIPY complexes. They were characterized first by complete ¹H, ¹¹B and ¹³C NMR spectroscopic assignments (CD₃Cl or CD₃C(O)CD₃); the molecular structures of 2a and 3a were determined by X-ray crystallography. Compounds 2a鈥?b>3a were studied by UV鈥搗is and fluorescence spectroscopy [桅_F = 0.27 卤 0.013 (2a); 0.024 卤 0.0016 (2b); 0.0034 卤 0.00047 (3a)]. Importantly, low [Cu²⁺] with 3a (<3.0 脳 10^鈥? M) gave rise to an increase of fluorescence intensity (off鈥搊n; 6.3-fold), whereas with 2a it decreased (on鈥搊ff). When [Hg²⁺] (<3.0 脳 10^鈥? M) was added to 2b, the 位_em,max value increased (off鈥搊n; 3.2-fold), and for 2a, it decreased (on鈥搊ff). The association constant (K_a) for Hg²⁺路2a was determined to be 3120 卤 307 M^鈥?. An approximate stoichiometric 1:1 binding determined by Job plot analysis is in line with successful DFT modeling of SSS-Cu²⁺ binding for this system type. ¹H NMR spectroscopy also revealed tentative sets of product complex peaks. These simple differences caused by formal ligand Me-group incorporation are the first for any related fluorophores, to the best of our knowledge.