Boron-Dipyrromethene-Functionalized Hemilabile Ligands as 鈥淭urn-On鈥?Fluorescent Probes for Coordination Changes in Weak-Link Approach Complexes

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• 作者：Alejo M. Lifschitz ; Chad M. Shade ; Alexander M. Spokoyny ; Jose Mendez-Arroyo ; Charlotte L. Stern ; Amy A. Sarjeant ; Chad A. Mirkin
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：May 6, 2013
• 年：2013
• 卷：52
• 期：9
• 页码：5484-5492
• 全文大小：402K
• 年卷期：v.52,no.9(May 6, 2013)
• ISSN：1520-510X

文摘

Herein we report a new class of hemilabile ligands with boron-dipyrromethene (Bodipy) fluorophores that, when complexed to Pt(II), can signal changes in coordination mode through changes in their fluorescence. The ligands consist of phosphino-amine or phosphino-thioether coordinating moieties linked to the Bodipy鈥檚 meso carbon via a phenylene spacer. Interestingly, this new class of ligands can be used to signal both ligand displacement and chelation reactions in a fluorescence 鈥渢urn-on鈥?fashion through the choice of weakly binding heteroatom in the hemilabile moiety, generating up to 10-fold fluorescence intensity increases. The Pt(II) center influences the Bodipy emission efficiency by regulating photoinduced electron transfer between the fluorophore and its meso substituent. The rates at which the excited Bodipy-species generate singlet oxygen upon excitation suggest that the heavy Pt(II) center also influences Bodipy鈥檚 emission efficiency by affecting intersystem crossing from the Bodipy excited singlet to excited triplet states. This signaling strategy provides a quantitative read-out for changes in coordination mode and potentially will enable the design of new molecular systems for sensing and signal amplification.