4980-19-2Relevant academic research and scientific papers
Twisted Hemithioindigo Photoswitches: Solvent Polarity Determines the Type of Light-Induced Rotations
Wiedbrauk, Sandra,Maerz, Benjamin,Samoylova, Elena,Reiner, Anne,Trommer, Florian,Mayer, Peter,Zinth, Wolfgang,Dube, Henry
supporting information, p. 12219 - 12227 (2016/10/03)
Controlling the internal motions of molecules by outside stimuli is a decisive task for the generation of responsive and complex molecular behavior and functionality. Light-induced structural changes of photoswitches are of special high interest due to the ease of signal application and high repeatability. Typically photoswitches use one reaction coordinate in their switching process and change between two more or less-defined states. Here we report on new twisted hemithioindigo photoswitches enabling two different reaction coordinates to be used for the switching process. Depending on the polarity of the solvent, either complete single bond (in DMSO) or double bond (in cyclohexane) rotation can be induced by visible light. This mutually independent switching establishes an unprecedented two-dimensional control of intramolecular rotations in this class of photoswitches. The mechanistic explanation involves formation of highly polar twisted intramolecular charge-transfer species in the excited state and is based on a large body of experimental quantifications, most notably ultrafast spectroscopy and quantum yield measurements in solvents of different polarity. The concept of pre-twisting in the ground state to open new, independent reaction coordinates in the excited state should be transferable to other photoswitching systems.
A curcumin-based molecular probe for near-infrared fluorescence imaging of tau fibrils in Alzheimer's disease
Park, Kwang-Su,Seo, Yujin,Kim, Mi Kyoung,Kim, Kyungdo,Kim, Yun Kyung,Choo, Hyunah,Chong, Youhoon
supporting information, p. 11194 - 11199 (2015/11/27)
In recent years, there has been growing interest in the near-infrared (NIR) fluorescence imaging of tau fibrils for the early diagnosis of Alzheimer's disease (AD). In order to develop a curcumin-based NIR fluorescent probe for tau fibrils, structural modification of the curcumin scaffold was attempted by combining the following rationales: the curcumin derivative should preserve its binding affinity to tau fibrils, and, upon binding to tau fibrils, the probe should show favorable fluorescence properties. To meet these requirements, we designed a novel curcumin scaffold with various aromatic substituents. Among the series, the curcumin derivative 1c with a (4-dimethylamino-2,6-dimethoxy)phenyl moiety showed a significant change in its fluorescence properties (22.9-fold increase in quantum yield; Kd, 0.77 μM; λem, 620 nm; Φ, 0.32) after binding to tau fibrils. In addition, fluorescence imaging of tau-green fluorescent protein-transfected SHSY-5Y cells with 1c confirmed that 1c detected tau fibrils in live cells.
A study of the effects of subunit pre-orientation for diarylpyrrole esters; design of new aryl-heteroaryl fluorescent sensors
Killoran, John,Gallagher, John F.,Murphy, Paul V.,O'Shea, Donal F.
, p. 1258 - 1265 (2007/10/03)
The synthesis, single crystal X-ray structures, spectroscopic properties and molecular mechanics calculations of three systematically substituted 3,5-diaryl-1H-pyrrole-2-carboxylic acid ethyl esters 1a-c are described. The goal is to develop design princi
