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Synthesis of Graphene Nanocomposites Toward the Enhancement of Energy Storage Performance for Supercapacitors
Published in Ashish Raman, Deep Shekhar, Naveen Kumar, Sub-Micron Semiconductor Devices, 2022
Monojit Mondal, Avik Sett, Dipak Kumar Goswami, Tarun Kanti Bhattacharyya
The reduction methods of GO are essential to minimize the defect sites to be device compatible. Various reduction techniques and different reducing agents have been developed to remove the functional groups of oxygen. It is very significant to note that no reduction technique can nullify the defects or remove the oxygen-containing sites as a whole. Hence, the reduction of GO has its maximum limit, and one of the most frequently used reducing agents is sodium borohydride (NaBH4). This reducing agent shows selective reduction toward aldehyde and ketone groups, but it is less effective in reducing ester and amide groups. The concentration of reducing NaBH4 in the reacting medium varies according to the graphene sheets. Numerous research groups have used halo acids as reducing agents, such as HCl, HI, and HBr, due to their specific reactivity to intercalated hydroxyl and epoxide groups [24]. One of the most potential reducing agents is hydrazine hydrate (N2H4), which several research groups used to reduce GO. Hydrazine readily forms hydrazone with the anchored carbonyl group and reacts with the oxygen and hydroxyl groups to form nitrogen and water.
Determinative Techniques to Measure Organics and Inorganics
Published in Paul R. Loconto, Trace Environmental Quantitative Analysis, 2020
Let us focus here on determining the various carbonyl compounds. Figure 4.78 shows an HPLC-uv (abbreviation for a high-performance liquid chromatograph with ultraviolet absorption detection) as a determinative technique for the separation and detection of the first six homologous series of aldehydes as their 2, 4-dinitrophenyl hydrazone derivatives, accomplished in the author’s laboratory. The reaction of aldehydes and ketones with 2, 4-dinitrophenyl hydrazine under mildly acidic conditions in water to form stable hydrazones is a well-known reaction in organic chemistry (pp. 319–325).69 The reaction of C3 (propionaldehyde or propanal) with 2, 4-dinitrophenyl hydrazine to yield the derivative is illustrated (without showing H atoms) below:
N-Heterocycles
Published in Navjeet Kaur, Metals and Non-Metals, 2020
Pyrazolo[3,4-b]pyridines [32] are an important class of heterocycles exhibiting a wide range of bioactivities and are structural analogs of purine bases. 5-Aminopyrazoles are useful intermediates for the preparation of pyrazolo[3,4-b]pyridines [32]. An efficient, one-pot synthesis of 5-sulfonamidopyrazoles can be performed from sulfonyl azides, terminal alkynes, and hydrazones. Hydrazones are easily synthesized from benzaldehydes and phenylhydrazines. They are used to trap the ketenimines produced in situ [33–34] and obtain cyclization products in a cascade process. This sequential process includes a three-component reaction with copper catalyst, an electrocyclic reaction with Lewis acid catalyst, and a dehydrogenation reaction (Scheme 11).
Synthesis, characterization and crystal structures of oxidovanadium(V) hydrazone complexes with antibacterial activity
Published in Journal of Coordination Chemistry, 2019
Vanadium has received considerable attention as a biologically important metal due to the existence of vanadoenzymes and other vanadium-containing biological molecules [1]. Another important biological activity of vanadium is its insulin-mimetic characteristic, which can cause in vivo stimulation of the uptake and metabolism of glucose [2]. Considering the side effects of inorganic vanadium salts, vanadium complexes have received particular interest for their pharmacological activities [3–8], their potential to model vanadium-containing nitrogenases [9] as well as haloperoxidases [10, 11]. Among the various ligands of vanadium complexes, Schiff bases derived from salicylaldehyde and its derivatives are widely adopted because of their biological activity and good coordination ability [12–15]. Hydrazones are a kind of special Schiff base compound which possess the functional group -CH = N-NH-C(O)-, which coordinates to metals either in keto or enol tautomeric form. Hydrazones possess a broad spectrum of biological activities [16–20]. Transition metal complexes derived from hydrazone compounds usually show effective antibacterial activities [21–24]. A literature survey reveals that vanadium complexes with hydrazones are rarely reported. In this article, two hydrazones, N’-(2-hydroxybenzylidene)-3-methylbenzohydrazide (H2L1) and N’-(2-hydroxybenzylidene)-3-methyl-4-nitrobenzohydrazide (H2L2), as the precursors were used to prepare vanadium complexes with VO(acac)2. The free hydrazones and the newly synthesized complexes, [VOL1(OMe)(MeOH)] (1) and [VOL2(OEt)(EtOH)] (2), were screened for their antibacterial activity with a view to explore new and efficient biocidal agents.
Review: Schiff base metal complexes as anti-inflammatory agents
Published in Journal of Coordination Chemistry, 2023
Qurat-Ul-Ain Sandhu, Muhammad Pervaiz, Abdul Majid, Umer Younas, Zohaib Saeed, Adnan Ashraf, Rana Rashad Mahmood Khan, Sami Ullah, Faisal Ali, Seemal Jelani
Hydrazone ligands are synthesized by reaction of aldehydes and ketones (carbonyl compounds) with hydrazine [5]. The acyl hydrazone and aroylhydrazone are two subclasses of hydrazone type ligands. The hydrazone ligands possessing only one donating atom are unidentate ligands but their sub groups contain two donating atoms as bidentate ligands. The hydrazones play a major role in selectivity of drug candidates.