scholarly journals Unexpected organic hydrate luminogens in the solid state

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Feng Zhou ◽  
Peiyang Gu ◽  
Zhipu Luo ◽  
Hari Krishna Bisoyi ◽  
Yujin Ji ◽  
...  
Keyword(s):  
Solid State ◽  
Deuterium Oxide ◽  
Isotope Effects ◽  
Fluorescence Emission ◽  
Structural Rearrangement ◽  
Water Molecules ◽  
Hydrogen Atoms ◽  
Keto Form ◽  
Practical Applications ◽  
Photoluminescent Materials

AbstractDeveloping organic photoluminescent materials with high emission efficiencies in the solid state under a water atmosphere is important for practical applications. Herein, we report the formation of both intra- and intermolecular hydrogen bonds in three tautomerizable Schiff-base molecules which comprise active hydrogen atoms that act as proton donors and acceptors, simultaneously hindering emission properties. The intercalation of water molecules into their crystal lattices leads to structural rearrangement and organic hydrate luminogen formation in the crystalline phase, triggering significantly enhanced fluorescence emission. By suppressing hydrogen atom shuttling between two nitrogen atoms in the benzimidazole ring, water molecules act as hydrogen bond donors to alter the electronic transition of the molecular keto form from nπ* to lower-energy ππ* in the excited state, leading to enhancing emission from the keto form. Furthermore, the keto-state emission can be enhanced using deuterium oxide (D2O) owing to isotope effects, providing a new opportunity for detecting and quantifying D2O.

Neutral 4-phenyl-1-[phenyl(pyridin-2-yl)methylidene]semicarbazide and its salt forms with inorganic anions

2019 ◽  
Vol 75 (1) ◽  
pp. 1-7
Author(s):  
Vinicius Oliveira Araujo ◽  
Bárbara Tirloni ◽  
Lívia Streit ◽  
Vânia Denise Schwade
Keyword(s):  
Solid State ◽  
Spectroscopic Characterization ◽  
Water Molecules ◽  
Keto Form ◽  
Chloride Dihydrate ◽  
Ir And Nmr Spectroscopy ◽  
Tautomeric Forms ◽  
Counter Ions ◽  
Salt Forms ◽  
Good Agreement

Semicarbazones can exist in two tautomeric forms. In the solid state, they are found in the keto form. This work presents the synthesis, structures and spectroscopic characterization (IR and NMR spectroscopy) of four such compounds, namely the neutral molecule 4-phenyl-1-[phenyl(pyridin-2-yl)methylidene]semicarbazide, C19H16N4O, (I), abbreviated as HBzPyS, and three different hydrated salts, namely the chloride dihydrate, C19H17N4O+·Cl−·2H2O, (II), the nitrate dihydrate, C19H17N4O+·NO3 −·2H2O, (III), and the thiocyanate 2.5-hydrate, C19H17N4O+·SCN−·2.5H2O, (IV), of 2-[phenyl({[(phenylcarbamoyl)amino]imino})methyl]pyridinium, abbreviated as [H2BzPyS]+·X −·nH2O, with X = Cl− and n = 2 for (II), X = NO3 − and n = 2 for (III), and X = SCN− and n = 2.5 for (IV), showing the influence of the anionic form in the intermolecular interactions. Water molecules and counter-ions (chloride or nitrate) are involved in the formation of a two-dimensional arrangement by the establishment of hydrogen bonds with the N—H groups of the cation, stabilizing the E isomers in the solid state. The neutral HBzPyS molecule crystallized as the E isomer due to the existence of weak π–π interactions between pairs of molecules. The calculated IR spectrum of the hydrated [H2BzPyS]+ cation is in good agreement with the experimental results.

Isotopieeffekte in den Hydratstrukturen von festem und gelöstem Kupfersulfat / Isotope effects in the hydrated structure of solid and aqueous copper sulphate

1972 ◽  
Vol 27 (5) ◽  
pp. 819-826 ◽  
Author(s):  
B Maiwald ◽  
K Heinzinger
Keyword(s):  
Copper Sulphate ◽  
Isotope Effects ◽  
Copper Ion ◽  
Hydrogen Isotopes ◽  
Bulk Water ◽  
Water Molecules ◽  
Hydrogen Atoms ◽  
Copper Sulphate Solution ◽  
Crystal Water ◽  
Lone Pairs

The fractionation of the oxygen isotopes of the water molecules in CuS04-5 H20 and in aqueous solutions of copper sulphate has been measured at 25 °C. In the total crystal water (G) three kinds of water can be distinguished by their binding: 1) The bisector of the two lone pairs directed to­wards the copper ion (Kj), 2) One of the lone pairs directed towards the copper ion (K2), 3) The two lone pairs directed towards two hydrogen atoms of water molecules coordinated with the cop­per ion (L). The water molecules in the copper sulphate solution are considered either hydration water (HW) or bulk water (FW). Defining a.\-B= (180/160)a/(180/180)b the following results have been obtained:There remains some doubt if the values attributed to ctKi-G and aK2-G have to be interchanged. The elementary cell of CuS04*5 H20 consists of two molecules. Four molecules of Kj-water are coordinated with one copper ion and four molecules of K2-water are coordinated with the second copper ion. The remaining two water molecules are of L-type. It is concluded from the results that on dehydration at temperatures below 50 °C first one copper ion loses it’s water and then the other. There is some doubt as to which group breaks up first. In addition, the results show that the L-type water becomes quantitatively the water of the monohydrate in agreement with the conclusions drawn from the results of the fractionation of the hydrogen isotopes in CuS04-5 H20. It is de­monstrated that, by considering only the overall fractionation of the oxygen or hydrogen isotopes between total crystal water and the saturated solution, wrong conclusions about the crystallization process could be drawn. In the case of CuCl2 solutions, it has been shown that the separation factor aHW-FW is sensi­tive towards changes in the structure of the solution.

Two Consecutive Magneto-Structural Gas-Solid Transformations with Single-Crystal Retention in Non-Porous Molecular Materials

2018 ◽  
Author(s):  
Julia Miguel-Donet ◽  
Javier López-Cabrelles ◽  
Nestor Calvo Galve ◽  
Eugenio Coronado ◽  
Guillermo Minguez Espallargas
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Structural Rearrangement ◽  
Magnetic Behaviour ◽  
Porous Solids ◽  
Potential Applications ◽  
Hcl Gas ◽  
Porous Coordination Polymer ◽  
Gas Molecules ◽  
Magnetostructural Transformation

<p>Modification of the magnetic properties in a solid-state material upon external stimulus has attracted much attention in the recent years for their potential applications as switches and sensors. Within the field of coordination polymers, gas sorption studies typically focus on porous solids, with the gas molecules accommodating in the channels. Here we present a 1D non-porous coordination polymer capable of incorporating HCl gas molecules, which not only causes a reordering of its atoms in the solid state but also provokes dramatic changes in the magnetic behaviour. Subsequently, a further solid-gas transformation can occur with the extrusion of HCl gas molecules causing a second structural rearrangement which is also accompanied by modification in the magnetic path between the metal centres. Unequivocal evidence of the two-step magnetostructural transformation is provided by X-ray single-crystal diffraction.</p>

Tracing H isotope effects in the dynamic metabolic network using multi-nuclear (1H, 2H and 13C) solid state NMR and GC–MS

2013 ◽  
Vol 57 ◽  
pp. 84-94 ◽  
Author(s):  
Ying Wang ◽  
Patrick Griffin ◽  
Katherine Jin ◽  
Marilyn L. Fogel ◽  
Andrew Steele ◽  
...  
Keyword(s):  
Solid State ◽  
Metabolic Network ◽  
Solid State Nmr ◽  
Isotope Effects

Mechanism of initiation in the thermal polymerization of styrene. Kinetic deuterium isotope effects in the initiation step of the thermal polymerization of some deuterated styrenes

1969 ◽  
Vol 47 (21) ◽  
pp. 4049-4058 ◽  
Author(s):  
Karl R. Kopecky ◽  
Syamalarao Evani
Keyword(s):  
Hydrogen Transfer ◽  
Deuterium Oxide ◽  
Isotope Effects ◽  
Thermal Polymerization ◽  
Convenient Synthesis ◽  
Initiation Step ◽  
Deuterium Isotope Effects

A convenient synthesis of 2,6-dideuteriostyrene starts with N,N-dimethyl-(1-phenylethyl)-amine which is deuterated in the 2 and 6 positions by a series of exchanges using n-butyllithium followed by deuterium oxide. The deuterium isotope effects at 70° on the rates of the thermal polymerization, [Formula: see text], of 2,6-dideuterio-, α-deuterio-, and β,β-dideuteriostyrene are 1.29, 1.00, and 0.78, respectively. The deuterium isotope effects at 70° on the 2,2′-azobis-(2-methylpropionitrile) initiated rates of polymerization,[Formula: see text], are 0.96, 0.86, and 0.81, respectively. From these values the deuterium isotope effects on the rates of initiation of the thermal polymerization, k1H/k1D, are calculated to be 1.80, 1.31, and 0.92, respectively. At 147° the presence of 1.5% potassium t-butoxide decreases the rate of the thermal polymerization of neat styrene by a factor of 17, and results in the formation of 1-phenyltetralin as the greatly predominant dimer. The results support the suggestion that the thermal polymerization of styrene is initiated by hydrogen transfer from 1-phenyl-1,2,3,9-tetrahydronaphthalene, formed by a concerted dimerization of two molecules of styrene, to a third molecule of styrene.

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