Browsing by Author "Shiva Kant Mishra"

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Green Solid-State Synthesis of Antibacterial Binary Organic Material: Crystal Growth, Physicochemical Properties, Thermal Study, Antibacterial Activity, and Hirshfeld Surface Analysis
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Adarsh Rai; Sumit Chaudhary; Surya Prakash Dube; Szymon Bajda; Richa Raghuwanshi; Shiva Kant Mishra; Gaetano Palumbo; Ramanand Rai
The organic compounds 2-aminopyrimidine (AP) and 4-aminobenzoic acid (PABA) were selected for the synthesis of a compound by establishing the phase diagram and adopting the solid-state synthesis method. The phase diagram analysis suggested the formation of a novel intermolecular compound (IMC) at a 1:1 stoichiometric ratio of AP and PABA, along with two eutectics at 0.25 and 0.90 mole fractions of AP. FTIR and NMR spectroscopy were used for the structure elucidation of the intermolecular compound. The powder X-ray diffraction analysis revealed the novel nature of IMC (APPABA) and the mechanical mixture nature of eutectics. The sharp and single peak of the DSC curve suggested the melting and pure nature of the synthesized IMC. Various thermodynamic parameters of IMC and eutectics were studied. A single crystal of the IMC was grown from solution and its single-crystal X-ray diffraction analysis revealed that it crystallized in a monoclinic system with the P21/n space group. Hirshfeld surface analysis further validated the weak non-covalent interactions summarized through the single-crystal X-ray analysis. Studies on the IMC were thoroughly conducted to evaluate its antibacterial activity with reference to antibiotics, and it showed significant positive responses against various pathogenic microbial isolates (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella aerogenes, and Shigella boydii) and non-pathogenic microbial isolates (Enterobacter cloacae, Pseudomonas azotoformans, and Burkholderia paludis). It was also found effective against methicillin-resistant bacterial strains viz. Staphylococcus aureus MRSA. © 2025 by the authors.
Photocatalytic Production of Oxygen by Nitrogen Doped Graphene Oxide Nanospheres: Synthesized via Bottom-Up Approach Using Dibenzopyrrole
(John Wiley and Sons Inc, 2022) Amit Kumar Verma; Prerna Tripathi; Zahoor Alam; Shiva Kant Mishra; Biswajit Ray; A.S.K. Sinha; Shikha Singh
In this article, we present the formation of nitrogen (N) doped graphene oxide nanospheres (N-GONs) and investigate their applicability for photocatalytic water splitting. We chose a simple “bottom-up” method for synthesizing N-GONs. Dibenzopyrrole as a basic structural unit was used for constructing N-GONs. Nitration is an intermediate step, subsequent hydrothermal treatment of nitro derivatives imparted oxygen functionalities, which was well proved via CHNS and XPS analysis. ∼14 % and 39 % of nitrogen and oxygen were present inside N-GONs. The average size of N-GONs is in-between 30–80 nm. N-GONs typically have a band gap of nearly 2.61 eV. The valance and the conduction bands alignments of N-GONs w.r.t to standard hydrogen electrode were evaluated through UPS and XPS studies. The alignments were found to be well suited for H2O splitting applications. N-GONs have n-type semiconductor features and a charge carrier density of 1.12×1022 cm−3. While studying photocatalytic dissociation of water we identified oxygen as the only product. Significantly, 1 g of N-GONs produced ∼1.3 mmol of oxygen over the course of 1 h. These backgrounds clearly suggest the possibilities of ongoing oxygen reduction and oxygen evolution reactions simultaneously. No-significant traces of H2O2 were observed which suggested immediate H2O2 disproportionation to O2 and H2O on N-GONs. The proposed photocatalytic activity of N-GONs is also confirmed by RRDE method for ORR catalysis. © 2022 Wiley-VCH GmbH.