China
Africa
Explore chapters and articles related to this topic
Photocatalysts Based on Covalent Organic Frameworks
Published in Tuan Anh Nguyen, Ram K. Gupta, Covalent Organic Frameworks, 2023
Nazanin Mokhtari, Mohammad Dinari
Recent studies introduced novel linkages in the preparation of COFs such as triptycene, benzoxazole, and benzothiazole. The mechanochemical grinding method was used to prepare a graphene-like layered triptycene-based COF utilized in photochemical degradation of rhodamine B [48]. Small molecules with benzoxazole moieties are used in the photogeneration of electrons. Benzoxazoles are traditionally prepared in a cascade reaction of o-aminophenols with aldehydes. Wang et al. [20] introduced three different benzoxazole-linked COFs (COF LZU-190, LZU-191, LZU-192) and compared their photocatalytic activity toward the transformation of arylboronic acids to phenols. The prepared COFs represent excellent features, including high stability, crystallinity, and high surface area. Among them, COF LZU-190 represents superior photocatalytic activity in phenol formation from arylboronic acids.
The Fluorescent Whitening of Textiles
Published in Menachem Lewin, Stephen B. Sello, Handbook of Fiber Science and Technology: Volume I Chemical Processing of Fibers and Fabrics, 2018
Raphael Levene, Menachem Lewin
All the general structural types which are suggested with cellulose are also effective in textile applications with the less polar polyamide fibers [2, 9, 30, 32, 101, 103–105]. These include DASC whiteners of both high and medium affinity, e.g., FWA 1 (Fig. 3.8) as well as FWA 5 (Fig. 3.13), triazole-stilbene disulfonic acids such as FWA 3a and DSBP whiteners, particularly FWA 2 (Fig. 3.8). Figure 3.13 shows some structures recommended particularly for polyamide. FWA 5 is less effective than FWA 2 [30]. Pyrazoline compounds, including FWAs 6a, 6b, are effective with polyamide [106] as is also the naphthotriazolestilbene derivative 7. These compounds all contain sulfonic acid groups and with polyamide act as acid dyes. In addition a group of neutral compounds can be applied to polyamide, exemplified by FWAs 8–10. They are applied as aqueous dispersions and are thus "disperse dye" types. They are also effective in washing powders. Coumarin whiteners (e.g., FWA 10) have poor lightfastness. Benzoxazole derivatives (Table 3.3) are also used for the whitening of polyamide textiles [13].
Microwave Synthetic Technology
Published in Banik Bimal Krishna, Bandyopadhyay Debasish, Advances in Microwave Chemistry, 2018
Biswa Mohan Sahoo, Bimal Krishna Banik, Jnyanaranjan Pa
Benzoxazoles under MW are routinely prepared in a two-step sequence comprising base-catalyzed bis-acylation of ortho-aminophenols followed by a Lewis-acid-assisted cyclization-dehydration reaction. Microwave flash heating of readily available acid chlorides and ortho-aminophenols in sealed reaction vessels delivered benzoxazoles in a one-pot process without the aid of any additive, such as base or Lewis acid [68].
A new cuprous coordinating polymer constructed by bridging 2,2-(1,4-butanediyl)bis-1,3-benzoxazole ligand: synthesis, structure, and properties
Published in Journal of Coordination Chemistry, 2019
Cong Wang, Yao Qu, Yancong Wu, Kesheng Shen, Kun Zhao, Chuang Li, Guozhen Huang, Xintong Han, Huilu Wu
Benzoxazole is a heterocyclic compound containing nitrogen and oxygen atoms having a non-centrosymmetric structure, and introducing substituents of different functions and structures on the oxazole ring to form benzoxazole derivatives having different structures and functions [14, 15]. Benzoxazole and its derivatives have a wide range of biological activities and good optical properties, and are widely used in various fields such as chemical engineering, aerospace, optoelectronic materials, life sciences, and medicine [16]. At the same time, benzoxazole and its derivatives have strong coordination ability and diverse coordination configurations [17]. Triphenylphosphine sulfide as a sulfur-containing ligand not only has a large steric hindrance to reduce the structural deformation of the copper(I) complexes, but also the unique electronic effect of the sulfur atom stabilizing the copper(I). Some cuprous complexes with benzoxazole or triphenylphosphine sulfide such as discrete monomers, dimeric clusters and CPs have been reported by several research groups [18–22]. The electronic and structural characteristics of the benzoxazole ligands play an important role in determining the overall structure of the copper(I) complexes and consequently their photophysical properties [23–25].
Synthesis, crystal structure, fluorescence and electrochemical properties of two Ag(I) complexes based on 2-(4′-pyridyl)-benzoxazole/SPPh3 ligands
Published in Journal of Coordination Chemistry, 2018
Shanshan Mao, Xintong Han, Chuang Li, Guozhen Huang, Kesheng Shen, Xinkui Shi, Huilu Wu
N-containing heterocyclic ligands, owing to the diversity of coordination modes and configurations, are typically used as neutral ligands in the synthesis of complexes [33, 34]. Azabicyclic ligands containing benzoxazoles are aromatic and may form π–π interactions and hydrogen bonding, resulting in the assembly of many supramolecular complexes with novel structures and special functions [35]. In recent years, benzoxazoles and their derivatives have been extensively studied because of their high nonlinear optical efficiency, biological activity, photostability, and transition metal binding ability [36, 37]. Therefore, benzoxazole derivatives and their metal complexes have been widely used in chemistry and applied medicine [38]. In addition, triphenylphosphine ligands are a good class of soft acids, which have a larger steric hindrance and rigid structure. Thus, the deformation properties of silver are reduced, resulting in the formation of stable silver(I) complexes [39]. In this work, we report the synthesis, structure, fluorescence studies, and electrochemical properties of two Ag(I) complexes containing 2-(4′-pyridyl)-benzoxazole or triphenylphosphine sulfide ligand.