scholarly journals Observation of crystallisation dynamics by crystal-structure-sensitive room-temperature phosphorescence from Au(I) complexes

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Yuki Kuroda ◽  
Masakazu Tamaru ◽  
Hitoya Nakasato ◽  
Kyosuke Nakamura ◽  
Manami Nakata ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Colour Change ◽  
Bulk Crystals ◽  
Room Temperature Phosphorescence ◽  
Change Mechanism ◽  
Aggregation Behaviour ◽  
Growth From Solution ◽  
Alkyl Side Chains ◽  
Colour Changes

Abstract The aggregation behaviour of Au(I) complexes in condensed phases can affect their emission properties. Herein, aggregation-induced room-temperature phosphorescence (RTP) is observed from the crystals of trinuclear Au(I) complexes. The RTP is highly sensitive to the crystal structure, with a slight difference in the alkyl side chains causing not only a change in the crystal structure but also a shift in the RTP maximum. Furthermore, in nanocrystals, reversible RTP colour changes are induced by phase transitions between crystal polymorphs during crystal growth from solution or the pulverisation of bulk crystals. The colour change mechanism is discussed in terms of intermolecular interactions in the crystal structure of the luminescent aggregates. The results suggest that the behaviour in nanocrystals may differ from that in bulk crystals. These insights will advance the fundamental understanding of crystallisation mechanisms and may aid in the discovery of new materials properties for solids with nano- to micrometre sizes.

scholarly journals Effects of Temperature on Colour of Selected Pig Organs in Silicone (S10) Plastination

2021 ◽  
Vol 5 (3) ◽  
pp. 324
Author(s):  
Tahmina Akhter ◽  
Mizanur Rahman Molla ◽  
Mahbub Alam ◽  
Tahmida Akhter ◽  
Farjana Akhond ◽  
...  
Keyword(s):  
Room Temperature ◽  
Colour Change ◽  
Resource Setting ◽  
Low Resource Setting ◽  
Temperature Group ◽  
Colour Changes ◽  
Background Temperature ◽  
Effects Of Temperature ◽  
The Difference ◽  
Medical University

Background: Temperature is one of the most important factors that are responsible for plastination procedure.Objective: The present study was designed to determine a suitable method of plastination of skeletal muscle in a low-resource setting in Bangladesh.Methods: This observational study was carried out in the Department of Anatomy, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh, between March 2015 and February 2016. Six whole pig kidneys (as firmer organ) and six whole pig lungs (as softer organs) were collected from a government authorized slaughterhouse in Dhaka city. Same numbers of organs were designated as ‘Cold Temperature Group’ and ‘Room Temperature Group’. We observed the change in colour at cold and room temperatures after different stages of plastination with a colour chart.Results: After fixation, both the brownish kidneys and reddish pink lungs turned brownish and darker. After dehydration, both the kidneys and lungs got paler. After forced impregnation, the colour turned much darker in both groups. The colour change continued towards a darker tone with time. The specific colour changes quantified into frequencies were very variable in both temperature groups.Conclusion: In observed colour changes, the difference was indeterminate.International Journal of Human and Health Sciences Vol. 05 No. 03 July’21 Page: 324-329

scholarly journals Fast Photo Stimulus Responsive Ultralong Room-temperature Phosphorescence Behaviour of Benzoic Acid Derivatives @ Boric acid

2021 ◽  
Author(s):  
Yi Cheng ◽  
Wenwen Fan ◽  
Longjie Wang ◽  
Yanxiong Liu ◽  
Qiufeng Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Benzoic Acid ◽  
Boric Acid ◽  
Room Temperature ◽  
Synthesis Process ◽  
Light Illumination ◽  
Room Temperature Phosphorescence ◽  
Benzoic Acid Derivatives ◽  
Stimulus Responsive

Abstract Ultralong room-temperature phosphorescence (URTP) materials with photo stimulus responsive (named URTP-PSR) behavior are amazing but still rarely reported due to their great requirements on the crystal structure, complicated synthesis process, long photo-activation and deactivation time. Herein, a series of URTP-PSR materials were prepared by a facile doping process, which involved one-pot heating treatment of benzoic acid derivatives and boric acid to form an amorphous phase. The URTP-PSR materials displayed gradually enhanced ultra-long phosphorescence upon prolonged deep UV light illumination under ambient conditions to restricts the vibration and rotation of molecular. Impressively, both of the photo-activation and deactivation process can be finished within several seconds, which was much fast than previously reported URTP-PSR materials. The optical properties can be repeated many times without obvious loosing performance, suggesting excellent fatigue resistance behaviors of the URTP-PSR materials. Simultaneously, the URTP-PSR materials also displayed excellent atmosphere stability, which still maintained good optical properties even under oxygen atmosphere. Furthermore, owing to the high processability and light-stimulus emission, the URTP-PSR materials have been utilized as security ink for anti-counterfeiting pattern application. It's worth mentioning that all the raw materials are commercialized and low-cost, which could be purchased directly and benefit for the practical application. These findings break through many limitations of existing dynamic RTP materials, such as complicated preparation process, fine crystal structure, long photo-activation and deactivation time, and furthermore expand the scope of dynamic smart-response materials for great potential in many fields.

scholarly journals Light-induced colour changes by the iridophores of the Neon tetra, Paracheirodon innesi

1987 ◽  
Vol 88 (5) ◽  
pp. 663-668
Author(s):  
JENNIFER CLOTHIER ◽  
J. N. LYTHGOE
Keyword(s):  
Plasma Membrane ◽  
Sodium Channels ◽  
Choline Chloride ◽  
Colour Change ◽  
Light Response ◽  
Sodium Ions ◽  
Constructive Interference ◽  
Change Mechanism ◽  
Reflected Light ◽  
Colour Changes

The iridophores of the Neon tetra Paracheirodon innesi consist of alternating layers of guanine and cytoplasm. In the dark-adapted state the reflected light from constructive interference is in the ultraviolet or blue. When exposed to light the cytoplasm layers increase in thickness and as a result the reflections shift to longer wavelengths and the iridophores appear green. The iridophores are thought to contain a rhodopsin-like molecule and we suggest that the colour-change mechanism involves the light-induced opening of sodium channels in the plasma membrane, leading osmotically to an increase in thickness of the cytoplasm layers. Experimental support for this suggestion was obtained by the substitution of choline chloride for sodium chloride in the perfusing medium, which can be done without altering the osmotic strength of the perfusing medium. This procedure almost abolished the light response and makes it seem likely that sodium ions are necessary for the light response to take place.

Lattice imaging and pore structure of β ferric oxyhydroxide

1978 ◽  
Vol 36 (1) ◽  
pp. 264-265
Author(s):  
T. Baird ◽  
J.R. Fryer ◽  
S.T. Galbraith
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bulk Material ◽  
Model Structure ◽  
Bulk Crystals ◽  
Lattice Imaging ◽  
Thin Sections ◽  
Ferric Oxyhydroxide ◽  
Resolution Electron ◽  
Hydrolysis Of

Introduction Previously we had suggested (l) that the striations observed in the pod shaped crystals of β FeOOH were an artefact of imaging in the electron microscope. Contrary to this adsorption measurements on bulk material had indicated the presence of some porosity and Gallagher (2) had proposed a model structure - based on the hollandite structure - showing the hollandite rods forming the sides of 30Å pores running the length of the crystal. Low resolution electron microscopy by Watson (3) on sectioned crystals embedded in methylmethacrylate had tended to support the existence of such pores.We have applied modern high resolution techniques to the bulk crystals and thin sections of them without confirming these earlier postulatesExperimental β FeOOH was prepared by room temperature hydrolysis of 0.01M solutions of FeCl3.6H2O, The precipitate was washed, dried in air, and embedded in Scandiplast resin. The sections were out on an LKB III Ultramicrotome to a thickness of about 500Å.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

DNA Inspirited Rational Construction of Nonconventional Luminophores with Efficient and Color-Tunable Afterglow

2020 ◽  
Author(s):  
Yunzhong Wang ◽  
Saixing Tang ◽  
Yating Wen ◽  
Shuyuan Zheng ◽  
Bing Yang ◽  
...  
Keyword(s):  
Rational Design ◽  
Room Temperature ◽  
Double Helix ◽  
Mechanical Grinding ◽  
Room Temperature Phosphorescence ◽  
Color Tunable ◽  
Potential Applications ◽  
Rational Construction ◽  
Double Helix Structure ◽  
Made In

<div>Persistent room-temperature phosphorescence (p-RTP) from pure organics is attractive </div><div>due to its fundamental importance and potential applications in molecular imaging, </div><div>sensing, encryption, anticounterfeiting, etc.1-4 Recently, efforts have been also made in </div><div>obtaining color-tunable p-RTP in aromatic phosphors5 and nonconjugated polymers6,7. </div><div>The origin of color-tunable p-RTP and the rational design of such luminogens, </div><div>particularly those with explicit structure and molecular packing, remain challenging. </div><div>Noteworthily, nonconventional luminophores without significant conjugations generally </div><div>possess excitation-dependent photoluminescence (PL) because of the coexistence of </div><div>diverse clustered chromophores6,8, which strongly implicates the possibility to achieve </div><div>color-tunable p-RTP from their molecular crystals assisted by effective intermolecular </div><div>interactions. Here, inspirited by the highly stable double-helix structure and multiple </div><div>hydrogen bonds in DNA, we reported a series of nonconventional luminophores based on </div><div>hydantoin (HA), which demonstrate excitation-dependent PL and color-tunable p-RTP </div><div>from sky-blue to yellowish-green, accompanying unprecedentedly high PL and p-RTP </div><div>efficiencies of up to 87.5% and 21.8%, respectively. Meanwhile, the p-RTP emissions are </div><div>resistant to vigorous mechanical grinding, with lifetimes of up to 1.74 s. Such robust, </div><div>color-tunable and highly efficient p-RTP render the luminophores promising for varying </div><div>applications. These findings provide mechanism insights into the origin of color-tunable </div><div>p-RTP, and surely advance the exploitation of efficient nonconventional luminophores.</div>

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>

scholarly journals Crystal structure of K[Hg(SCN)3] – a redetermination

2014 ◽  
Vol 70 (9) ◽  
pp. i46-i46 ◽  
Author(s):  
Matthias Weil ◽  
Thomas Häusler
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
Three Dimensional ◽  
Lattice Parameters ◽  
Bond Lengths ◽  
Dimensional Network ◽  
Anisotropic Displacement Parameters ◽  
Precision And Accuracy ◽  
Standard Deviations ◽  
Atomic Coordinates

The crystal structure of the room-temperature modification of K[Hg(SCN)3], potassium trithiocyanatomercurate(II), was redetermined based on modern CCD data. In comparison with the previous report [Zhdanov & Sanadze (1952).Zh. Fiz. Khim.26, 469–478], reliability factors, standard deviations of lattice parameters and atomic coordinates, as well as anisotropic displacement parameters, were revealed for all atoms. The higher precision and accuracy of the model is, for example, reflected by the Hg—S bond lengths of 2.3954 (11), 2.4481 (8) and 2.7653 (6) Å in comparison with values of 2.24, 2.43 and 2.77 Å. All atoms in the crystal structure are located on mirror planes. The Hg2+cation is surrounded by four S atoms in a seesaw shape [S—Hg—S angles range from 94.65 (2) to 154.06 (3)°]. The HgS4polyhedra share a common S atom, building up chains extending parallel to [010]. All S atoms of the resulting1∞[HgS2/1S2/2] chains are also part of SCN−anions that link these chains with the K+cations into a three-dimensional network. The K—N bond lengths of the distorted KN7polyhedra lie between 2.926 (2) and 3.051 (3) Å.

scholarly journals Tipping the Balance with the Aid of Stoichiometry: Room Temperature Phosphorescence versus Fluorescence in Organic Cocrystals

2015 ◽  
Vol 15 (4) ◽  
pp. 2039-2045 ◽  
Author(s):  
Simone d’Agostino ◽  
Fabrizia Grepioni ◽  
Dario Braga ◽  
Barbara Ventura
Keyword(s):  
Room Temperature ◽  
Room Temperature Phosphorescence
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