Open AccessCyanine Conformational Restraint in the Far-Red Range
Author(s) -
Megan S. Michie,
Roland Götz,
Christian Franke,
Matthew M. Bowler,
Nikita Kumari,
Valentin Magidson,
Marcia Levitus,
Jadranka Lončarek,
Markus Sauer,
Martin J. Schnermann
Publication year - 2017
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.7b07272
Subject(s) - chemistry , cyanine , quantum yield , molecule , photochemistry , excited state , fluorescence , yield (engineering) , organic chemistry , physics , materials science , quantum mechanics , nuclear physics , metallurgy
Far-red cyanine fluorophores find extensive use in modern microscopy despite modest quantum yields. To improve the photon output of these molecules, we report a synthetic strategy that blocks the major deactivation pathway: excited-state trans-to-cis polyene rotation. In the key transformation, a protected dialdehyde precursor undergoes a cascade reaction to install the requisite tetracyclic ring system. The resulting molecules exhibit the characteristic features of conformational restraint, including improved fluorescence quantum yield and extended lifetime. Moreover, these compounds recover from hydride reduction with dramatically improved efficiency. These observations enable efficient single-molecule localization microscopy in oxygenated buffer without addition of thiols. Enabled by modern organic synthesis, these studies provide a new class of far-red dyes with promising spectroscopic and chemical properties.