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Application of Biocides and Chemical Treatments to Both Combat Microorganisms and Reduce (Bio)Corrosion
Published in Torben Lund Skovhus, Dennis Enning, Jason S. Lee, Microbiologically Influenced Corrosion in the Upstream Oil and Gas Industry, 2017
Brandon E. L. Morris, Geert M. van der Kraan
This molecule contains a severely electron-deficient carbon at its center, which is caused by the combination of the bromine group and the hydroxyl (-OH) R-groups (Paulus 2005). In its pure form, bronopol is a solid white powder that is miscible with water up to 280 grams per liter. The biocidal efficacy of bronopol is different under oxic and anoxic conditions. In oxygen-saturated water, its target is the amino acid cysteine; the reaction with this amino acid forms oxidizing agents by converting the cysteine to cystine (holding a disulfide bond), which can interfere with various cellular processes. When no oxygen is present, the molecule reacts with various nucleophilic components present inside a cellular body. Typically, this active is applied for longer-term applications as the rate of reactive is not quick, and longer contact times are needed for effective treatment of a system. The molecule is mainly used in the tight and shale gas industry due to its rapid degradation in slightly alkaline environments. Disadvantages of the molecule are extreme sensitivity toward sulfides, and its instability in heated environments above 40°C. Significant performance with bronopol is best achieved when combined with other biocidal actives.
Grafting a mesomorphic Schiff base onto gold nanoparticle via ester link – photoluminescence, mesomorphism, electrical conductivity and antioxidant activity
Published in Liquid Crystals, 2019
Nirmalendu Das, Debasish Borah, Himadri Acharya, Sudip Choudhury, S. Krishna Prasad, D.S. Shankar Rao, Chira R. Bhattacharjee
Organic-inorganic blends are considered ideal system for effective charge transfer, a prerequisite for high performance hybrid solar cell [36,37]. The room temperature AC conductivity of the newly synthesised LC molecule was recorded to be 5.26 × 10−8 S/m. When tagged to GNP surface, there occurred a pronounced enhancement of conductivity (2.94 × 10−2 S/m) in the GNP-LC composite material by about 106 times, entering the semiconducting domain. This has relevance to potential application in photovoltaic solar cells, light emitting diodes, thin film transistors and sensors [38], photoacoustic [39,40] etc. The hike in conductivity may be accounted by invoking a charge transfer complex between highly delocalised pi-electron rich organic moiety of the LC molecule and the electron deficient GNPs that provide a tunnelling path for electronic conduction [41–43]. While enhancement in conductivity of LC molecules in the GNP-LC composite has also been noted earlier [44,45], the marked increase observed in the present case is quite unprecedented.
Oxidations of aromatic sulfides promoted by the phthalimide N-oxyl radical (PINO)
Published in Journal of Sulfur Chemistry, 2023
Marika Di Berto Mancini, Alessandro Tabussi, Marianna Bernardini, Osvaldo Lanzalunga
These results, taken together with the observation of fragmentation products in the oxidation of alkyl aryl sulfides 4 and 5 (vide infra), support the operation of an electron transfer (ET) mechanism (Scheme 1). An initial ET process likely occurring in a π-stacked charge transfer complex formed by the electron-deficient aryl ring of PINO and the thioanisole donor aryl group, as previously found by us in the hydrogen transfer reaction from phenolic substrates to PINO [35,36], leads to the formation a sulfide radical cation/PINO- couple (6). The ET step (a) is endergonic on the basis of the lower redox potential of PINO (E° = 0.69 V vs SCE) [37] with respect to thioanisoles (see Table 1). This step is followed by an attack of the PINO- to the radical cation to form the radical adduct 7 (Scheme 1, path b). This intermediate then undergoes a further one electron oxidation by another PINO or PhI(OAc)2 still present in solution, to generate an oxysulfonium cation (Scheme 1, path c). The latter species might react with the small amount of water present in the solvent to form the NHPI and the sulfoxide (Scheme 1, path d). In accordance with the mechanism in Scheme 1, when the oxidation was carried out in the presence of H218O ca 50% of the labeled product C6H5S18OCH3 was formed (see Figure S12). It is interesting to note that the production of sulfoxide by reaction of the sulfide radical cation with PINO anion differentiate our system from other way of generation of sulfoxides via the intermediacy of the corresponding radical cations produced by photoinduced ET where the oxygen source of the product is O2 [38–40].
Structural evolution and bonding characteristics of neutral Cs2B n clusters
Published in Molecular Physics, 2022
Hang Yang, Yan-Fei Hu, Jun-Jie Ding, Yu-Quan Yuan, Yu Zhao
Boron and its compounds have attracted the extensive attention of researchers because of their abundant excellent properties and chemical structures in recent years [1]. In the meantime, it is also used as hydrogen storage [2] and drug delivery carrier [3] material. The electron-deficient state in which the valence electrons of the B atom are less than the number of valence orbitals, it is beneficial to form covalent bond molecules with most atoms through delocalised multi-centre bonds, so that the properties and structures of boron compounds are rich and diverse. The electron-deficient boron tends to generate planar or quasi-planar clusters at small as well as medium sizes [4], with aromatic structures similar to hydrocarbons [5], this is owing to the π-electron delocalised bonds in the Bn clusters fit the Hückel rule of aromaticity and antiaromaticity in cyclic hydrocarbons [6,7,8]. The delocalised π or σ bonds in Bn clusters predicted by Zubarev [9] and Boldyrev [10] exhibit aromaticity or antiaromaticity. A typical example is the neutral B14 cluster, whose 3D structure was redefined as a planar structure with aromaticity [11]. Among the neutral pure boron clusters, the clusters with an atomic number less than 16 are almost all planar structures, especially the Bn clusters when n = 7–15, which have been proved to be planar structures with aromaticity by experimental and theoretical studies [6,12]. In 2007, Oger's team [13] reported that the B16+ cluster is an intermediate structure of a plane-to-cylindrical when studying cationic boron clusters, namely the minimum value of the first three-dimensional structure appears at n = 17. In the anion system of pure boron clusters [8,14], the planar or quasi-planar structures up to 25 B atoms, even higher anionic boron clusters (B35,36−) continue to exhibit a planar pattern with a hexagonal central hexagonal hole [15,16]. In addition, it was found from Boustani's study [15] that B19 exhibits different structural skeletons at different charge states: B19− is a two-dimensional structure, but neutral and cation B19 are both 3D pyramidal structures, their results show that electrons can influence the geometry of boron clusters. Therefore, it is of great necessity for us to study the 2D and 3D structures of boron clusters in different electronic states for understanding their structural evolution characteristics.