Contrasting 1D tunnel-structured and 2D layered polymorphs of V2O5: relating crystal structure and bonding to band gaps and electronic structure

2016 ◽  
Vol 18 (23) ◽  
pp. 15798-15806 ◽  
Author(s):  
Thomas M. Tolhurst ◽  
Brett Leedahl ◽  
Justin L. Andrews ◽  
Peter M. Marley ◽  
Sarbajit Banerjee ◽  
...  

An elucidation of structure–property relationships in V2O5 polymorphs using synchrotron X-ray spectroscopy and density functional theory calculations.

2017 ◽  
Vol 19 (2) ◽  
pp. 1551-1559 ◽  
Author(s):  
Marco Taddei ◽  
Davide Tiana ◽  
Nicola Casati ◽  
Jeroen A. van Bokhoven ◽  
Berend Smit ◽  
...  

Structure–property relationships in mixed-linker UiO-66 were disclosed using high-resolution powder X-ray diffraction and density functional theory calculations.


Molecules ◽  
2020 ◽  
Vol 25 (2) ◽  
pp. 273 ◽  
Author(s):  
Sudheer S. Kurup ◽  
Richard J. Staples ◽  
Richard L. Lord ◽  
Stanislav Groysman

Synthesis of new chromium(II) complexes with chelating bis(alkoxide) ligand [OO]Ph (H2[OO]Ph = [1,1′:4′,1′’-terphenyl]-2,2′’-diylbis(diphenylmethanol)) and their subsequent reactivity in the context of catalytic production of carbodiimides from azides and isocyanides are described. Two different Cr(II) complexes are obtained, as a function of the crystallization solvent: mononuclear Cr[OO]Ph(THF)2 (in toluene/THF, THF = tetrahydrofuran) and dinuclear Cr2([OO]Ph)2 (in CH2Cl2/THF). The electronic structure and bonding in Cr[OO]Ph(THF)2 were probed by density functional theory calculations. Isolated Cr2([OO]Ph)2 undergoes facile reaction with 4-MeC6H4N3, 4-MeOC6H4N3, or 3,5-Me2C6H3N3 to yield diamagnetic Cr(VI) bis(imido) complexes; a structure of Cr[OO]Ph(N(4-MeC6H4))2 was confirmed by X-ray crystallography. The reaction of Cr2([OO]Ph)2 with bulkier azides N3R (MesN3, AdN3) forms paramagnetic products, formulated as Cr[OO]Ph(NR). The attempted formation of a Cr–alkylidene complex (using N2CPh2) instead forms chromium(VI) bis(diphenylmethylenehydrazido) complex Cr[OO]Ph(NNCPh2)2. Catalytic formation of carbodiimides was investigated for the azide/isocyanide mixtures containing various aryl azides and isocyanides. The formation of carbodiimides was found to depend on the nature of organoazide: whereas bulky mesitylazide led to the formation of carbodiimides with all isocyanides, no carbodiimide formation was observed for 3,5-dimethylphenylazide or 4-methylphenylazide. Treatment of Cr2([OO]Ph)2 or H2[OO]Ph with NO+ leads to the formation of [1,2-b]-dihydroindenofluorene, likely obtained via carbocation-mediated cyclization of the ligand.


Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 464 ◽  
Author(s):  
Hebboul ◽  
Galez ◽  
Benbertal ◽  
Beauquis ◽  
Mugnier ◽  
...  

Synthesis and characterization of anhydrous LiZn(IO3)3 powders prepared from an aqueous solution are reported. Morphological and compositional analyses were carried out by using scanning electron microscopy and energy-dispersive X-ray measurements. The synthesized powders exhibited a needle-like morphology after annealing at 400 °C. A crystal structure for the synthesized compound was proposed from powder X-ray diffraction and density-functional theory calculations. Rietveld refinements led to a monoclinic structure, which can be described with space group P21, number 4, and unit-cell parameters a = 21.874(9) Å, b = 5.171(2) Å, c = 5.433(2) Å, and  = 120.93(4)°. Density-functional theory calculations supported the same crystal structure. Infrared spectra were also collected, and the vibrations associated with the different modes were discussed. The non-centrosymmetric space group determined for this new polymorph of LiZn(IO3)3, the characteristics of its infrared absorption spectrum, and the observed second-harmonic generation suggest it is a promising infrared non-linear optical material.


2021 ◽  
Author(s):  
Rodrigo Carvalho ◽  
Cleber Marchiori ◽  
Viorica-Alina Oltean ◽  
Stéven Renault ◽  
Tom Willhammar ◽  
...  

Organic-based materials are potential candidates for a new generation of sustainable and environmentally friendly battery technologies, but insights are currently missing into the structural, kinetic and thermodynamic properties of how...


2010 ◽  
Vol 114 (50) ◽  
pp. 13175-13181 ◽  
Author(s):  
Rolf W. Berg ◽  
Anders Riisager ◽  
Olivier N. Van Buu ◽  
Steffen Buus Kristensen ◽  
Rasmus Fehrmann ◽  
...  

Author(s):  
Zoulikha Hebboul ◽  
Christine Galez ◽  
Djamal Benbertal ◽  
Sandrine Beauquis ◽  
Yannick Mugnier ◽  
...  

Synthesis and characterization of anhydrous LiZn(IO3)3 powders prepared from an aqueous solution are reported. Morphological and compositional analyses were carried out by scanning electron microscopy and energy dispersive X-ray measurements. The synthesized powders exhibit a needle-like morphology after annealing at 400°C. A crystal structure for the synthesized compound has been proposed from powder X-ray diffraction and density-functional theory calculations. Rietveld refinements led to a monoclinic structure, which can be described with space group P21, number 4, and unit-cell parameters a = 21.874(9) Å, b = 5.171(2) Å, c = 5.433(2) Å, and beta = 120.93(4)º. Density-functional theory calculations supported the same crystal structure. Infrared spectra were also collected and the vibrations associated to the different modes discussed. The non-centrosymmetric space group determined for this new polymorph of LiZn(IO3)3, the characteristics of its infrared absorption spectrum, and the observed second harmonic generation suggest a promising infrared non-linear optical material.


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