Spectrophotometric and photocatalytic studies of H-bonded charge transfer complex of oxalic acid with imidazole: single crystal XRD, experimental and DFT/TD-DFT studies

2019 ◽  
Vol 43 (23) ◽  
pp. 9039-9051 ◽  
Author(s):  
Ishaat M. Khan ◽  
Kehkashan Alam ◽  
Mohammad Jane Alam ◽  
Musheer Ahmad

The photocatalytic activity of a new CT complex was tested. Spectrophotometric studies were performed to understand its formation through N+–H⋯O− hydrogen bonding, and the structure was confirmed by single crystal XRD.

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1463
Author(s):  
Lucas A. Almeida ◽  
Margarita Habran ◽  
Rafael dos Santos Carvalho ◽  
Marcelo E. H. Maia da Costa ◽  
Marco Cremona ◽  
...  

The improvement of photocatalytic activity of TiO2-based nanomaterials is widely investigated due to the tentative of their industrialization as environmental photocatalysts and their inherently low solar spectrum sensitivity and rapid recombination of charge carriers. Coupling of oxygen-based bidentate diketone to nanocrystalline TiO2 represents a potential alternative for improving the holdbacks. Formation of TiO2-acetylacetone charge transfer complex (CTC) by sol-gel route results in a hybrid semiconductor material with photodegradation activity against toxic NOx gas. In this research, the influence of the chelating agent acetylacetone (ACAC) content on the CTC photocatalytic efficiency under visible light was evaluated. A high content of ACAC in the CTC is not a decisive factor for efficiency of photocatalytic reactions. In fact, the highest efficiency for NOx degradation (close to 100%, during 1 h of visible light exposure) was reported for the material calcined in air at 300 °C with the content of strongly bonded acetylacetone not higher than 3 wt.%. Higher calcination temperature (400 °C) left TiO2 almost completely depleted in ACAC, while at the highest applied temperature (550 °C) a portion of anatase was transformed into rutile and the sample is free of ACAC. The analyses pointed out that superoxide anion radical (O2−) plays an active role in photo-oxidation of NOx. Our findings indicate that this CTC has both high visible light spectral sensitivity and photocatalytic efficiency.


2012 ◽  
Vol 554-556 ◽  
pp. 792-795
Author(s):  
Hai Xing Liu ◽  
Jing Wang ◽  
Fang Fang Jian ◽  
Hui Juan Yue ◽  
Guang Zeng ◽  
...  

A new Eu complex [Eu (C3O9H6)] ·2(H2O) has been synthesized from a hydrothermal reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. The Eu atom is coordinated by eight O atoms. The molecular is antisymmetric structure by the C3-C3 axis. It is striking that the structure of the complex exhibits extensive O-H…O hydrogen-bonding interactions.


Author(s):  
Yuki Nakagawa ◽  
Yukihiro Takahashi ◽  
Jun Harada ◽  
Tamotsu Inabe

In the ionic charge-transfer (CT) complex composed of bis(ethylenedithio)tetrathiafulvalene (ET) and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), C10H8S8·C8Cl2N2O2, the donor and acceptor molecules both form centrosymmetric dimers associated by strong face-to-face π–π interactions. The disordered DDQ molecules form a one-dimensional π-stacked column, while the ET molecules form a two-leg ladder through additional short S...S contacts between adjacent π–π-bonded dimers. The crystal structure of ET–DDQ revealed in this study will provide a valuable example of the two-leg spin ladder system, which has rarely been reported for ET-based CT complexes.


1987 ◽  
Vol 40 (12) ◽  
pp. 2097 ◽  
Author(s):  
DJ Fuller ◽  
DL Kepert ◽  
BW Skelton ◽  
AH White

Crystal structure determinations of (LH)2(B10H10), (1), and (LH2)(B10H10), (2), L = 2,2'- bipyridine , have been carried out by single-crystal X-ray diffraction methods at 295 K, being refined by full-matrix least squares to residuals of 0.041, 0.047 for 1758, 1771 'observed' independent reflections respectively. Crystals of (1) are monoclinic, P21/n, a 12.040(7), b 17.71(1), c 11.142(4) �, β 101.78(4)�, Z 4. Crystals of (2) are monoclinic, P21/c, a 9.937(4), b 10.837(3), c 14.856(5) �, β 109 2l(3)�, Z 4. The colour of the compounds is accounted for by charge-transfer interactions of a novel type, namely between the positively charged cationic acid hydrogen atoms and the negatively charged non-apical hydrogen atoms of the anion. In yellow (1), these distances are 2.26(5) �, while in red (2), they are much shorter, being 1.89(4), 1.97(3) �.


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