Photoswitchable Magnetic Resonance Imaging Contrast by Improved Light-Driven Coordination-Induced Spin State Switch
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- 作者：Marcel Dommaschk ; Morten Peters ; Florian Gutzeit ; Christian Sch眉tt ; Christian N盲ther ; Frank D. S枚nnichsen ; Sanjay Tiwari ; Christian Riedel ; Susann Boretius ; Rainer Herges
- 刊名：Journal of the American Chemical Society
- 出版年：2015
- 出版时间：June 24, 2015
- 年：2015
- 卷：137
- 期：24
- 页码：7552-7555
- 全文大小：293K
- ISSN：1520-5126
文摘
We present a fully reversible and highly efficient on鈥搊ff photoswitching of magnetic resonance imaging (MRI) contrast with green (500 nm) and violet-blue (435 nm) light. The contrast change is based on intramolecular light-driven coordination-induced spin state switch (LD-CISSS), performed with azopyridine-substituted Ni-porphyrins. The relaxation time of the solvent protons in 3 mM solutions of the azoporphyrins in DMSO was switched between 3.5 and 1.7 s. The relaxivity of the contrast agent changes by a factor of 6.7. No fatigue or side reaction was observed, even after >100鈥?00 switching cycles in air at room temperature. Electron-donating substituents at the pyridine improve the LD-CISSS in two ways: better photostationary states are achieved, and intramolecular binding is enhanced.