scholarly journals Quantitative prediction and interpretation of spin energy gaps in polyradicals: the virtual magnetic balance

2017 ◽  
Vol 19 (13) ◽  
pp. 9039-9044 ◽  
Author(s):  
Vincenzo Barone ◽  
Ivo Cacelli ◽  
Alessandro Ferretti ◽  
Giacomo Prampolini
Keyword(s):  
Room Temperature ◽  
Organic Molecules ◽  
Open Shell ◽  
Quantitative Prediction ◽  
Energy Gaps ◽  
Sufficient Stability ◽  
Unpaired Electrons ◽  
Magnetic Balance

Open-shell organic molecules possessing more than two unpaired electrons and sufficient stability at room temperature are very unusual, but some of them were recently synthesized and promise a number of fascinating applications.

Room Temperature Alkali Metal Reduction of Carbon Dioxide

2020 ◽  
Author(s):  
Lucas A. Freeman ◽  
Akachukwu D. Obi ◽  
Haleigh R. Machost ◽  
Andrew Molino ◽  
Asa W. Nichols ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Room Temperature ◽  
Chemical Reduction ◽  
Bond Cleavage ◽  
Open Shell ◽  
Metal Reduction ◽  
One Pot ◽  
Earth Abundant ◽  
Electron Reduction

The reduction of the relatively inert carbon–oxygen bonds of CO<sub>2</sub> to access useful CO<sub>2</sub>-derived organic products is one of the most important fundamental challenges in synthetic chemistry. Facilitating this bond-cleavage using earth-abundant, non-toxic main group elements (MGEs) is especially arduous because of the difficulty in achieving strong inner-sphere interactions between CO<sub>2</sub> and the MGE. Herein we report the first successful chemical reduction of CO<sub>2</sub> at room temperature by alkali metals, promoted by a cyclic(alkyl)(amino) carbene (CAAC). One-electron reduction of CAAC-CO<sub>2</sub> adduct (<b>1</b>) with lithium, sodium or potassium metal yields stable monoanionic radicals clusters [M(CAAC–CO<sub>2</sub>)]<sub>n</sub>(M = Li, Na, K, <b> 2</b>-<b>4</b>) and two-electron alkali metal reduction affords open-shell, dianionic clusters of the general formula [M<sub>2</sub>(CAAC–CO<sub>2</sub>)]<sub>n </sub>(<b>5</b>-<b>8</b>). It is notable that these crystalline clusters of reduced CO<sub>2</sub> may also be isolated via the “one-pot” reaction of free CO<sub>2</sub> with free CAAC followed by the addition of alkali metals – a reductive process which does not occur in the absence of carbene. Each of the products <b>2</b>-<b>8</b> were investigated using a combination of experimental and theoretical methods.<br>

Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores

2019 ◽  
Author(s):  
Shuyuan Zheng ◽  
Taiping Hu ◽  
Xin Bin ◽  
Yunzhong Wang ◽  
Yuanping Yi ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Efficiency ◽  
Spin Orbit Coupling ◽  
Design Rationale ◽  
Emission Mechanism ◽  
Room Temperature Phosphorescence ◽  
Electronic Interactions ◽  
Energy Gaps ◽  
Theoretical Results

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>

Can an ammonium-based room temperature ionic liquid counteract the urea-induced denaturation of a small peptide?

2017 ◽  
Vol 19 (11) ◽  
pp. 7772-7787 ◽  
Author(s):  
Soumadwip Ghosh ◽  
Souvik Dey ◽  
Mahendra Patel ◽  
Rajarshi Chakrabarti
Keyword(s):  
Ionic Liquid ◽  
Aqueous Medium ◽  
Room Temperature ◽  
Organic Molecules ◽  
Room Temperature Ionic Liquid ◽  
Small Peptide ◽  
Small Organic Molecules

The folding/unfolding equilibrium of proteins in aqueous medium can be altered by adding small organic molecules generally termed as co-solvents.

scholarly journals Assessment of the KID Procedure on a Mo–oxo Complex, an Open–Shell System

2020 ◽  
Author(s):  
Jorge Martínez-Araya ◽  
Daniel Glossman-Mitnik
Keyword(s):  
Density Functional ◽  
Organic Molecules ◽  
Open Shell ◽  
Density Functionals ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
Shell System ◽  
Global And Local ◽  
First Time ◽  
Local Reactivity Descriptors

The KID (Koopmans in DFT) procedure usually applies in organic molecules of the closed&ndash;shell type. We used the KID procedure in an open&ndash;shell system for the first time to choose the most suitable density functional to compute global and local reactivity descriptors coming from the Conceptual Density&ndash;Functional Theory. From a set of 18 density functionals spread from the second until the fourth rung of the Jacob&rsquo;s ladder: BP86, B97-D, BLYP, CAM-B3LYP, M06-L, M11-L, MN12-L, B3LYP, PBE0, N12-SX, M06-2X, M11, MN12-SX, CAM-B3LYP, LC-&omega;HPBE, &omega;B97X-D, APFD, MN15 and MN15-L, we concluded that CAM-B3LYP provides the best outcome.

Room-Temperature Ceramic Nanocoating Using Nanosheet Deposition Technique

2013 ◽  
Vol 2013 (CICMT) ◽  
pp. 000014-000018 ◽  
Author(s):  
M. Osada ◽  
T. Sasaki
Keyword(s):  
Room Temperature ◽  
Organic Molecules ◽  
Structural Diversity ◽  
Layer By Layer ◽  
Precise Control ◽  
Langmuir Blodgett ◽  
Wide Range ◽  
Potential Applications ◽  
Layer Assembly ◽  
Selection Of

We present a novel procedure for ceramic nanocoating using oxide nanosheet as a building block. A variety of oxide nanosheets (such as Ti1−δO2, MnO2 and perovsites) were synthesized by delaminating appropriate layered precursors into their molecular single sheets. These nanosheets are exceptionally rich in both structural diversity and electronic properties, with potential applications including conductors, semiconductors, insulators, and ferromagnets. Another attractive aspect is that nanosheets can be organized into various nanoarchitectures by applying solution-based synthetic techniques involving electrostatic layer-by-layer assembly and Langmuir-Blodgett deposition. It is even possible to tailor superlattice assemblies, incorporating into the nanosheet galleries with a wide range of materials such as organic molecules, polymers, and inorganic/metal nanoparticles. Sophisticated functionalities or paper-like devices can be designed through the selection of nanosheets and combining materials, and precise control over their arrangement at the molecular scale.

scholarly journals Complex Uranyl Dichromates Templated by Aza-Crowns

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 462 ◽  
Author(s):  
Oleg Siidra ◽  
Evgeny Nazarchuk ◽  
Dmitry Charkin ◽  
Stepan Kalmykov ◽  
Anastasiya Zadoya
Keyword(s):  
Aqueous Solutions ◽  
Crown Ethers ◽  
Room Temperature ◽  
Organic Molecules ◽  
Negative Charge ◽  
Uranyl Compounds ◽  
One Dimensional ◽  
Chain Complexes ◽  
Aza Crown Ethers

Three new uranyl dichromate compounds templated by aza-crown templates were obtained at room temperature by evaporation from aqueous solutions: (H2diaza-18-crown-6)2[(UO2)2(Cr2O7)4(H2O)2](H2O)3 (1), (H4[15]aneN4)[(UO2)2(CrO4)2(Cr2O7)2(H2O)] (H2O)3.5 (2) and (H4Cyclam)(H4[15]aneN4)2[(UO2)6(CrO4)8(Cr2O7)4](H2O)4 (3). The use of aza-crown templates made it possible to isolate unprecedented and complex one-dimensional units in 2 and 3, whereas the structure of 1 is based on simple uranyl-dichromate chains. It is very likely that the presence of relatively large organic molecules of aza-crown ethers does not allow uranyl chromate chain complexes to condense into the units of higher dimensionality (layers or frameworks). In general, the formation of 1, 2, and 3 is in agreement with the general principles elaborated for organically templated uranyl compounds. The negative charge of the [(UO2)(Cr2O7)2(H2O)]2−, [(UO2)2(CrO4)2(Cr2O7)2(H2O)]4− and [(UO2)3(CrO4)4(Cr2O7)2]6− one-dimensional inorganic motifs is compensated by the protonation of all nitrogen atoms in the molecules of aza-crowns.

Bose–Einstein Condensation of Exciton-Polaritons in Organic Microcavities

2020 ◽  
Vol 71 (1) ◽  
pp. 435-459 ◽  
Author(s):  
Jonathan Keeling ◽  
Stéphane Kéna-Cohen
Keyword(s):  
Room Temperature ◽  
Organic Molecules ◽  
Einstein Condensation ◽  
Electronic Excitations ◽  
Optical Mode ◽  
Optical Cavities ◽  
Bose Einstein Condensation ◽  
Exciton Polaritons ◽  
Basic Physics ◽  
Bose Einstein

Bose–Einstein condensation describes the macroscopic occupation of a single-particle mode: the condensate. This state can in principle be realized for any particles obeying Bose–Einstein statistics; this includes hybrid light-matter excitations known as polaritons. Some of the unique optoelectronic properties of organic molecules make them especially well suited for the realization of polariton condensates. Exciton-polaritons form in optical cavities when electronic excitations couple collectively to the optical mode supported by the cavity. These polaritons obey bosonic statistics at moderate densities, are stable at room temperature, and have been observed to form a condensed or lasing state. Understanding the optimal conditions for polariton condensation requires careful modeling of the complex photophysics of organic molecules. In this article, we introduce the basic physics of exciton-polaritons and condensation and review experiments demonstrating polariton condensation in molecular materials.

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