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Synthesis of LDH for Photocatalytic Removal of Toxic Dyes from Aqueous Solution
Published in Satya Bir Singh, Prabhat Ranjan, A. K. Haghi, Materials Modeling for Macro to Micro/Nano Scale Systems, 2022
Rasna Devi, Dipshikha Bharali, Ramesh Chandra Deka
Dyes can be defined as colored substances, which bind to the substrate to which it is being applied. Dyes possess colors because they absorb light in the visible region of the electromagnetic spectrum (400–800 nm). The basic structural component responsible for the color is a chromophore group. A chromophore can be defined as substance that has nearly same absorption wavelength as that of the considering dye or as that of the substructure, which is electronically related to the dye [14]. Chromophores possess conjugated system having alternate double and single bonds. Electrons are delocalized in this conjugated system and therefore resonance of electrons occurs. Generally, chromophores contain heteroatoms like N, O, S that have nonbonding electrons. Some of commonly found chromophores in dyes are shown in Scheme 5.2. Apart from the chromophores, most dyes have another structural group, which is called auxochromes or color helpers. Although auxochromes are not directly responsible for furnishing colors of dyes, their presence can enhance the color of a colorant and influence solubility of the dye. For example, benzene itself does not show any color, but when attached to –NH2 it imparts yellowish color. Some commonly known auxochromes are –NH2, –OH, –NHR, –NR2, –COOH, –HSO3, etc.
Exotic Solar Technologies
Published in Anco S. Blazev, Solar Technologies for the 21st Century, 2021
Conjugated polymers are some of the most promising solar energy generating systems for use in some specialized niche markets. A conjugated system is formed when carbon atoms covalently bond with alternating single and double bonds in hydrocarbons. The hydrocarbons’ electrons pz orbitals delocalize and form a delocalized bonding π orbital with a π* antibonding orbital.
Optics of Organic Nanomaterials
Published in Vladimir I. Gavrilenko, Optics of Nanomaterials, 2019
One of the examples of the conjugated system is the octatetraene which has the following structure: () CH2−CH=CH−CH=CH−CH=CH−CH2
Molecular structural, vibrational assignments, electronic structure and DFT calculations, and molecular docking of N-benzylideneaniline and N-salicylidene-o-aminoaphenol Schiff bases
Published in Inorganic and Nano-Metal Chemistry, 2021
Ramadan M. Ramadan, Mohamed M. Abo-Aly, Alaa A. M. Lasheen
The use of Schiff bases represents a vital importance in the chemistry of organic and coordination compounds.[1–4] The importance of these compounds are stemmed from their applications as models in biological, medicinal and bioinorganic chemistry,[5,6] and their uses in medicine, drugs, industrial catalysis, chemical analysis, corrosion and photochromism.[7–9] Also, the spectroscopic studies of these derivatives especially the vibrational spectral modes and their related electronic structures attracts much attention.[10,11] Notably, the photophysical properties for excited-state intramolecular proton transfer (ESIPT) reactions of N-salicylidene-o-aminophenol (SAP) were reported.[12] Furthermore, the crystal structure of N-benzylideneaniline (BZA) showed that its V-shaped structure has a twisted angle between 36° and 55°. The conformation of N-benzlideneaniline is non-planar and it is different from its homologues azobenzene and stilbene derivatives.[13–15] Using ab initio calculations, it was also concluded an analogous finding and showed that the mainly stable conformation of N-benzlideneaniline has been attributed to a compromise between steric interactions and delocalization of the double bond link and/or nitrogen lone pair electrons with the conjugated system.[16]
Synthesis of a 2,4-DcCoPc/MIL-101(Fe) composite and catalytic oxidation of styrene to benzaldehyde
Published in Journal of Coordination Chemistry, 2021
Yanbing Yin, Zhaosong Xin, Hang Yang, Guopeng Xu, Yang Liu, Xiaolong LI
Phthalocyanine has a structure of tetraazatetrabenzoporphyrin. It has an 18-electron macrocyclic conjugated system in the molecule. Its central nitrogen has a strong coordination ability and can be coordinated with almost all metals to form a metal phthalocyanine [29–31]. Metal phthalocyanines have excellent optical, electrical, thermal, magnetic and catalytic properties and good chemical stability [32]. As a catalyst, phthalocyanine is easy to aggregate and difficult to recover after the reaction [33]. When cobalt phthalocyanine is used as a separate catalyst for catalytic oxidation, the catalytic activity of the cobalt center may be affected by other groups on the phthalocyanine ring [34]. Therefore, using a suitable carrier to support the metal phthalocyanine in order to prevent the catalytic activity of the metal phthalocyanine from being reduced and prevent secondary pollution is needed [35].
Recent developments of doped g-C3N4 photocatalysts for the degradation of organic pollutants
Published in Critical Reviews in Environmental Science and Technology, 2021
Xiaolu Liu, Ran Ma, Li Zhuang, Baowei Hu, Jianrong Chen, Xiaoyan Liu, Xiangke Wang
g-C3N4 for water-splitting was reported in 2009, which offered up a fire-new direction to study its photocatalytic performance (Wang et al., 2009). To date, it has wide applications in the fields of new energy catalysis, environmental pollution improvement, photo-electrocatalysis and organic catalysis (Ye, Wang, Wu, & Yuan, 2015). The lone pair electron of nitrogen plays a vital role in the g-C3N4’s electronic structure, which endows g-C3N4 constructed by tri-s-triazine units with special electronic structure (Li, Ma, et al., 2017). The two-dimensional (2D) layered nanostructures with π conjugated system and an opportune energy gap (∼2.7 eV) endow g-C3N4 unique optoelectronic property, suitable conduction band position and high chemical stability (Sun & Liang, 2017). But, the photocatalytic activity of g-C3N4 is not satisfactory, such as the relative low visible-light absorbance, rapid recombination of photogenerated electron holes pairs and poor specific surface area (Zhu, Xiao, Li, & Carabineiro, 2014). Thereby, the practical applications of g-C3N4 are still limited by these shortcomings. Similarly, these disadvantages lead to the low quantum efficiency of g-C3N4, which is about 0.1% with irradiation of 420–460 nm light wavelength (Liu, 2016).