scholarly journals Structural Water Molecules Confined in Soft and Hard Nanocavities as Bright Color Emitters

2021 ◽  
Author(s):  
Jiafeng Zhou ◽  
Taiqun Yang ◽  
Bo Peng ◽  
Bingqian Shan ◽  
Meng Ding ◽  
...  
Keyword(s):  
Water Molecules ◽  
Structural Water ◽  
Bright Color

scholarly journals Origin of the Bright Photoluminescence of Thiolate-protected Gold Nanoclusters: Confined Structural Water Molecules as Real Emitters

2021 ◽  
Author(s):  
Bo Peng ◽  
kun zhang
Keyword(s):  
Gold Nanoclusters ◽  
Electron Interaction ◽  
Water Molecules ◽  
Photoluminescence Intensity ◽  
Metal Nanoclusters ◽  
Structural Water ◽  
Ligand Interactions ◽  
Interfacial States ◽  
Bright Color ◽  
Interfacial Adsorption

The availability of a range of excited states has enriched zero-, one- and two- dimensional quantum nanomaterials with interesting luminescence properties, in particular for noble metal nanoclusters (NCs) as typical examples. But, the elucidation and origin of optoelectronic properties remains elusive. In this report, using widely used Au(I)-alkanethiolate complex (Au(I)-SRs, R = -(CH2)12H) with AIE characteristics as a model system, by judiciously manipulating the delicate surface ligand interactions at the nanoscale interface, together with a careful spectral investigations and an isotope diagnostic experiment of heavy water (D2O), we evidenced that the structural water molecules (SWs) confined in the nanoscale interface or space are real emitter centers for photoluminescence (PL) of metal NCs and the aggregate of Au(I)-SRs complexes, instead of well-organized metal core dominated by quantum confinement mechanics. Interestingly, the aggregation of Au(I)-SRs generated dual fluorescence-phosphorescence emission and the photoluminescence intensity was independent on the degree of aggregation but showed strong dependency on the content and state of structural water molecules (SWs) confined in the aggregates. SWs are different from traditional hydrogen bonded water molecules, wherein, due to interfacial adsorption or spatial confinement, the p orbitals of two O atoms in SWs can form a weak electron interaction through spatial overlapping, which concomitantly constructs a group of interfacial states with π bond characteristics, consequently providing some alternative channels (or pathways) to the radiation and/or non-radiation relaxation of electrons. Our results provide completely new insights to understand the fascinating properties (including photoluminescence, catalysis and chirality, etc.) of other low-dimension quantum dots and even for aggregation-induced emission luminophores (AIEgens). This also answers the century old debate on whether and how water molecules emit bright color.

scholarly journals Gas Transfer of Metals during the Destruction of Efflorescent Sulfates from the Belovo Plant Sulfide Slag, Russia

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 344
Author(s):  
Svetlana Bortnikova ◽  
Natalya Abrosimova ◽  
Nataliya Yurkevich ◽  
Valentina Zvereva ◽  
Anna Devyatova ◽  
...  
Keyword(s):  
Major And Trace Elements ◽  
Water Molecules ◽  
Gas Transfer ◽  
Structural Water ◽  
Fermentation Products ◽  
X Ray ◽  
Gas Condensates ◽  
Gas Phase Transport ◽  
Phase Transport

This paper demonstrates the results of experiments for the determination of the composition of gases during the dehydration of sulfates (Na-jarosite, melanterite, and chalcanthite) collected at the surface of pyrometallurgical waste heaps. The volatilization of various elements, and vapor–gas phase transport from three sulfate groups were investigated by stepwise laboratory heating at 45, 55, and 65 °C. The sample of yellow efflorescence mainly consisted of Na-jarosite, the white efflorescence contained melanterite as the major mineral, and the blue efflorescence sample consisted of chalcanthite. These all contained a few impurities up to 5 %. The highest total dissolved solids (TDS) was found in the gas condensates from melanterite (59 mg/L), followed by chalcanthite (29 mg/L) and Na-jarosite (17 mg/L). It was determined that major and trace elements in the condensate can be trapped by water vapor and can migrate with the vapor phase during the desorption and dehydration of hydrous sulfates. X-ray diffractograms showed that Na-jarosite remained stable throughout the temperature range, whilst the separation of melanterite’s structural water occurred at 40 °C, and chalcanthite completely lost two water molecules at 50 °C. The gas condensates contained acetates and formates, which could be the fermentation products of bacterial communities. Some of the strains—Micrococcaceae sp., Bacillus sp., and Microbacteriaceae sp.—were cultivated.

Article

1999 ◽  
Vol 77 (5-6) ◽  
pp. 733-737
Author(s):  
Maurice M Kreevoy ◽  
Victor G Young, Jr.
Keyword(s):  
Isotope Effect ◽  
Dihedral Angle ◽  
Room Temperature ◽  
Isotope Effects ◽  
Water Molecules ◽  
Aromatic Rings ◽  
Structural Water ◽  
The Mean ◽  
Increasing Temperature ◽  
Ubbelohde Effect

The crystal structure of sodium hydrogen bis(4-nitrophenoxide) dihydrate, 1, with deuterium replacing hydrogen in the bridge and the structural water molecules, has been determined crystallographically at 113, 173, and 295 K. The structure of 1 had previously been determined at similar temperatures (Kreevoy et al.). The O,O distances are 1.5-1.7 pm greater in the deuterated compound than in the undeuterated, at all three temperatures, providing another example of an Ubbelohde effect in a Speakman-Hadzi compound. The temperature invariance of the Ubbelohde effect at temperatures up to room temperature is evidence against centralization of the hydron within this temperature range. It has previously been suggested (Kreevoy et al.) that simplification of the IR spectrum of 1 with increasing temperature is due to an increase in the rate of the hydron shift between the two basic oxygens. This suggestion is strengthened by the elimination of hydron centralization as an alternative. The O,O distance in 1 also increases with temperature, and the dihedral angle between the mean planes of the two aromatic rings decreases. Similarly, the increase in the O,O distance with isotopic substitution is accompanied by a small decrease in the dihedral angle; another geometric isotope effect. Ubbelohde effects in Speakman-Hadzi compounds make the geometric isotope effects found computationally in the critical complexes for hydron, hydrogen atom, or hydride transfer more credible.Key words: low-barrier hydrogen bond, Speakman-Hadzi compound, geometric isotope effect, Ubbelohde effect.

Caged structural water molecules emit tunable brighter colors by topological excitation

Nanoscale ◽  
2021 ◽  
Author(s):  
Taiqun Yang ◽  
Xiaodan Hu ◽  
Bing-Qian Shan ◽  
Bo Peng ◽  
Jiafeng Zhou ◽  
...  
Keyword(s):  
Free Water ◽  
Water Molecules ◽  
Structural Water ◽  
Colorless Liquid ◽  
Topological Excitation

Intrinsically, free water molecules are colorless liquid. If it is colorful, why and how does it emit the bright colors? We provided direct evidences that, when water was trapped into...

Defect microstructures in garnet, omphacite and symplectite from UHP eclogites, eastern Dabieshan, China: a TEM and FTIR study

2008 ◽  
Vol 72 (5) ◽  
pp. 1057-1069 ◽  
Author(s):  
Xiuling Wu ◽  
Dawei Meng ◽  
Xiaoyu Fan ◽  
Xin Meng ◽  
Jianping Zheng ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Slip System ◽  
Early Stage ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Structural Water ◽  
Deformation Structures ◽  
Dislocation Movement ◽  
Defect Microstructures ◽  
Water Contents

AbstractGarnets, omphacite and the minerals of a clinopyroxene/amphibole/plagioclase symplectite in UHP eclogites from Yingshan, Dabieshan have been investigated by TEM and Micro-FTIR. TEM reveals that the predominant microstructures in eclogites and symplectite-forming minerals are chain multiplicity faults (CMFs), dislocation substructures, clusters of water molecules up to ∼50 nm in diameter and recrystallized grains ∼1.75 μm in diameter. This indicates dynamic recrystallization of omphacite, probably during an eclogite-facies metamorphic episode. The deformation structures in symplectite-forming minerals were produced by plastic deformation related to an amphibolite-facies retrograde metamorphic event. CMFs described in the present work demonstrate the existence of an infrequent ½<011> (010) slip system for P2/n omphacite from an UHP eclogite sample from Dabieshan. The frequent occurrence of CMFs in omphacite suggests that they indicate an important deformation mechanism in omphacite and shows that this slip system plays a significant role in the deformation and recovery of eclogite. The hydrous components of deformed minerals may cause plastic deformation of the rocks by dislocation movement and accelerate retrograde metamorphism. Micro-FTIR results show that all the garnets and omphacites contain structural water occurring as hydroxyl groups (OH) or water (H2O). The structural water contents in omphacite range from 110—710 ppm and in garnet from 0—180 ppm. Water released during decompression might supply an early-stage retrograde metamorphic fluid.

A monomeric TIM-barrel structure fromPyrococcus furiosusis optimized for extreme temperatures

2012 ◽  
Vol 68 (11) ◽  
pp. 1479-1487 ◽  
Author(s):  
Heidi Repo ◽  
Jesper S. Oeemig ◽  
Janica Djupsjöbacka ◽  
Hideo Iwaï ◽  
Pirkko Heikinheimo
Keyword(s):  
Main Chain ◽  
Pyrococcus Furiosus ◽  
Ion Pairs ◽  
Industrial Applications ◽  
Side Chain ◽  
Water Molecules ◽  
Extreme Temperatures ◽  
Structural Water ◽  
Hyperthermophilic Archaeon ◽  
Tim Barrel

The structure of phosphoribosyl anthranilate isomerase (TrpF) from the hyperthermophilic archaeonPyrococcus furiosus(PfTrpF) has been determined at 1.75 Å resolution. ThePfTrpF structure has a monomeric TIM-barrel fold which differs from the dimeric structures of two other known thermophilic TrpF proteins. A comparison of thePfTrpF structure with the two known bacterial thermophilic TrpF structures and the structure of a related mesophilic protein fromEscherichia coli(EcTrpF) is presented. The thermophilic TrpF structures contain a higher proportion of ion pairs and charged residues compared with the mesophilicEcTrpF. These residues contribute to the closure of the central barrel and the stabilization of the barrel and the surrounding α-helices. In the monomericPfTrpF conserved structural water molecules are mostly absent; instead, the structural waters are replaced by direct side-chain–main-chain interactions. As a consequence of these combined mechanisms, theP. furiosusenzyme is a thermodynamically stable and entropically optimized monomeric TIM-barrel enzyme which defines a good framework for further protein engineering for industrial applications.

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