Hydrogen Bond Exchange and Ca2+ Binding of Aqueous N-Methylacetamide Revealed by 2DIR Spectroscopy

2020 ◽  
Vol 124 (32) ◽  
pp. 6947-6954 ◽  
Author(s):  
Olivia M. Cracchiolo ◽  
Danielle K. Geremia ◽  
Steven A. Corcelli ◽  
Arnaldo L. Serrano
Keyword(s):  
Hydrogen Bond ◽  
2Dir Spectroscopy

Femtosecond 2DIR spectroscopy of the nitrile stretching vibration of thiocyanate anions in liquid-to-supercritical heavy water. Spectral diffusion and libration-induced hydrogen-bond dynamics

2015 ◽  
Vol 17 (44) ◽  
pp. 29776-29785 ◽  
Author(s):  
Denis Czurlok ◽  
Michael von Domaros ◽  
Martin Thomas ◽  
Jeannine Gleim ◽  
Jörg Lindner ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Heavy Water ◽  
Spectral Diffusion ◽  
Two Dimensional ◽  
Stretching Vibration ◽  
2Dir Spectroscopy ◽  
Hydrogen Bond Dynamics

Femtosecond two-dimensional infrared (2DIR) spectroscopy was carried out to study the dynamics of vibrational spectral diffusion of the nitrile stretching vibration of thiocyanate.

A Hydrogen Bond Between Linear Tetrapyrrole and Conserved Aspartate Causes the Far-Red Shifted Absorption of Phytochrome Photoreceptors

2020 ◽  
Author(s):  
Egle Maximowitsch ◽  
Tatiana Domratcheva
Keyword(s):  
Hydrogen Bond ◽  
Light Adaptation ◽  
Positive Charge ◽  
Pyrrole Ring ◽  
Md Simulations ◽  
Spectral Shift ◽  
Specific Domain ◽  
Study Guides ◽  
Rational Engineering ◽  
Tuning Mechanism

Photoswitching of phytochrome photoreceptors between red-absorbing (Pr) and far-red absorbing (Pfr) states triggers light adaptation of plants, bacteria and other organisms. Using quantum chemistry, we elucidate the color-tuning mechanism of phytochromes and identify the origin of the Pfr-state red-shifted spectrum. Spectral variations are explained by resonance interactions of the protonated linear tetrapyrrole chromophore. In particular, hydrogen bonding of pyrrole ring D with the strictly conserved aspartate shifts the positive charge towards ring D thereby inducing the red spectral shift. Our MD simulations demonstrate that formation of the ring D–aspartate hydrogen bond depends on interactions between the chromophore binding domain (CBD) and phytochrome specific domain (PHY). Our study guides rational engineering of fluorescent phytochromes with a far-red shifted spectrum.

Probing the Structural Features and the Micro-heterogeneity of Various Deep Eutectic Solvents and their Water Dilutions by the Photophysical Behaviour of Two Fluorophores

2020 ◽  
Author(s):  
Matteo Tiecco ◽  
Irene Di Guida ◽  
Pier Luigi Gentili ◽  
Raimondo Germani ◽  
Carmela Bonaccorso ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Deep Eutectic Solvents ◽  
Structural Features ◽  
Solvation Dynamics ◽  
Structured Systems ◽  
Reduced Viscosity ◽  
Bond Network ◽  
Fluorescent Molecules

<div><div><div><p>The structural features of a series of diverse Deep Eutectic Solvents (DESs) have been investigated and characterized by means of two fluorescent probes. The spectral and photophysical properties of the latter are strictly dependent on the experienced environment, so that they can provide insights into the polarity, viscosity, hydrogen-bond network, and micro-heterogeneity of the various DESs.</p><p>In fact, the investigated DESs exhibit a variety of properties with regards to their hydrophilicity, acidity, and hydrogen-bond ability, and these details were deeply probed by the two fluorescent molecules. The effect of the addition of water, which is a key strategy for tuning the properties of these structured systems, was also tested. In particular, the excited state dynamics of the probes, measured by femtosecond-resolved transient absorption, proved instrumental in understanding the changes in the structural properties of the DESs, namely reduced viscosity and enhanced heterogeneity, as the water percentage increases. Differences between the various DESs in terms of both local microheterogeneity and bulk viscosity also emerged from the peculiar multi-exponential solvation dynamics undergone by the excited states of the probes.</p></div></div></div>

Probing the Structural Features and the Micro-heterogeneity of Various Deep Eutectic Solvents and their Water Dilutions by the Photophysical Behaviour of Two Fluorophores

2020 ◽  
Author(s):  
Matteo Tiecco ◽  
Irene Di Guida ◽  
Pier Luigi Gentili ◽  
Raimondo Germani ◽  
Carmela Bonaccorso ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Deep Eutectic Solvents ◽  
Structural Features ◽  
Solvation Dynamics ◽  
Structured Systems ◽  
Reduced Viscosity ◽  
Bond Network ◽  
Fluorescent Molecules

<div><div><div><p>The structural features of a series of diverse Deep Eutectic Solvents (DESs) have been investigated and characterized by means of two fluorescent probes. The spectral and photophysical properties of the latter are strictly dependent on the experienced environment, so that they can provide insights into the polarity, viscosity, hydrogen-bond network, and micro-heterogeneity of the various DESs.</p><p>In fact, the investigated DESs exhibit a variety of properties with regards to their hydrophilicity, acidity, and hydrogen-bond ability, and these details were deeply probed by the two fluorescent molecules. The effect of the addition of water, which is a key strategy for tuning the properties of these structured systems, was also tested. In particular, the excited state dynamics of the probes, measured by femtosecond-resolved transient absorption, proved instrumental in understanding the changes in the structural properties of the DESs, namely reduced viscosity and enhanced heterogeneity, as the water percentage increases. Differences between the various DESs in terms of both local microheterogeneity and bulk viscosity also emerged from the peculiar multi-exponential solvation dynamics undergone by the excited states of the probes.</p></div></div></div>

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