Akbar Mohammad

Design and construction of a ferrocene based inclined polycatenated Co-MOF for supercapacitor and dye adsorption applications

A new cobalt based inclined polycatenated metal–organic framework, {[Co4(FcDCA)4(bpy)4(H2O)6]·11H2O}n [FcDCA = 1,1′-ferrocene dicarboxylic acid and bpy = 4,4′-bipyridyl] (1), has been designed and synthesized in a facile manner. 1 can be simplified as a 2D + 2D → 3D inclined polycatenation class with Doc1/1, as authenticated by single crystal X-ray studies. Further, 1 was employed as a modifier for a glassy carbon electrode (1-GCE) without using any binders to explore its supercapacitor performance. Detailed electrochemical investigations carried out using 1-GCE reveal a specific capacitance of 446.8 F g−1 at a current density of 1.2 A g−1, with an excellent cycle life of ∼88.37% (after 800 cycles). Moreover, a high rate performance was also observed for 1-GCE (it retains 81% of its initial capacitance up to a high current density of 10 A g−1), which endorsed its good stability on the electrode surface. The results were found to be superior than those for {[Co(bpy)1.5(NO3)2]}n (2), highlighting the role of the presence of FcDCA in 1. Additionally, the notable adsorption and desorption properties of 1 towards selected Chicago Sky Blue (CSB) and Congo Red (CR) dyes confirms the candidature of 1 as a potential dye adsorbing agent.

Fabrication of innovative ZnO nanoflowers showing drastic biological activity

The present study deals with the synthesis of ZnO nanoflowers (ZnO-1 and ZnO-2) at room temperature using new structurally characterized single molecular precursors (1 and 2). 1, 2 and ZnO-1 were explored for their potential to reduce the viability of the Gram-negative bacteria Escherichia coli.1 and 2 were found to be promising antibacterial agents, while the ZnO nanoflowers demonstrated a relatively non-toxic nature. 1, 2 and ZnO-1 were further evaluated for DNA binding and cleavage behaviour. 1 and 2 showed strong binding affinity towards CT-DNA compared to ZnO-1. In addition, all the three compounds demonstrated oxidative cleavage of pBluescript plasmid DNA in the presence of H2O2.

Construction of TiO2 nanosheets modified glassy carbon electrode (GCE/TiO2) for the detection of hydrazine

TiO2 nanosheets were synthesized via solvothermal method and characterized using powder x-ray diffraction (PXRD), UV–vis spectroscopy, scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) mapping. A binder free hydrazine sensor was fabricated by modifying the glassy carbon electrode (GCE) with TiO2 nanosheets, using simple drop casting method (GCE/TiO2). The modified GCE/TiO2 was employed for detection of hydrazine which exhibited a very high sensitivity of 70 μA mM−1 cm−2 with a limit of detection (LOD), 28 μM using cyclic voltammetry whereas a highest sensitivity 330 μA mM−1 cm−2 and LOD, 150 μM was obtained by employing square wave voltammetry.

Reduction of selective polyaromatic nitrotriptycene via an azoxytriptycene intermediate under ambient conditions using a cobalt/cobalt oxide nanocomposite (CoNC)

A cobalt-based nanocomposite (CoNC) has been prepared from a recently reported single source molecular precursor (SSMP) [CoII(hep-H)(H2O)4]SO4 (A) (hep-H = 2-(2-hydroxylethyl)pyridine). The resulting nanocomposite material was characterized by using various physicochemical techniques such as XRD, SEM, EDAX, TEM and XPS spectroscopy. X-ray diffraction patterns show the weakly crystalline nature of the catalyst. This was also confirmed by the SAED pattern obtained from HR-TEM. XPS analysis reveals the formation of metallic cobalt and the cobalt oxide (CoO) nanocomposite. CoNC was employed for the facile catalytic hydrogenation of 2-nitrotriptycene (M1) and 2,6,14-trinitrotriptycene (M2) as model substrates under atmospheric reaction conditions, which otherwise takes place either with RANEY® Nickel, Pd/C or SnCl2/HCl catalysts under harsh conditions. The mechanistic pathway reveals that the reduction of M1 proceeds via the intermediacy of azoxy triptycene (III) and N-hydroxylamine triptycene (IV).

Facile Access to Amides from Oxygenated or Unsaturated Organic Compounds by Metal Oxide Nanocatalysts Derived from Single-Source Molecular Precursors

Oxidative amidation is a valuable process for the transformation of oxygenated organic compounds to valuable amides. However, the reaction is severely limited by the use of an expensive catalyst and limited substrate scope. To circumvent these limitations, designing a transition-metal-based nanocatalyst via more straightforward and economical methodology with superior catalytic performances with broad substrate scope is desirable. To resolve the aforementioned issues, we report a facile method for the synthesis of nanocatalysts NiO and CuO by the sol-gel-assisted thermal decomposition of complexes [Ni(hep-H)(H2O)4]SO4 (SSMP-1) and [Cu(μ-hep)(BA)]2 (SSMP-2) [hep-H = 2-(2-hydroxylethyl)pyridine; BA = benzoic acid] as single-source molecular precursors (SSMPs) for the oxidative amidation of benzyl alcohol, benzaldehyde, and BA by using N,N-dimethylformamide (DMF) as the solvent and as an amine source, in the presence of tert-butylhydroperoxide (TBHP) as the oxidant, at T = 80 °C. In addition to nanocatalysts NiO and CuO, our previously reported Co/CoO nanocatalyst (CoNC), derived from the complex [CoII(hep-H)(H2O)4]SO4 (A) as an SSMP, was also explored for the aforementioned reaction. Also, we have carefully investigated the difference in the catalytic performance of Co-, Ni-, and Cu-based nanoparticles synthesized from the SSMP for the conversion of various oxygenated and unsaturated organic compounds to their respective amides. Among all, CuO showed an optimum catalytic performance for the oxidative amidation of various oxygenated and unsaturated organic compounds with a broad reaction scope. Finally, CuO can be recovered unaltered and reused for several (six times) recycles without any loss in catalytic activity.

Thiophene-containing thiolato dimers, oxygen inserted Cu(II) complex, crystal structures, molecular docking and theoretical studies

Abstract Reactions of n-butyl- and n-octyl-thiophene with CS2 at 0 °C resulted in thiolate dimers 1 and 2, respectively. The reaction of 1 with Cu(NO3)2·3H2O in methanol under ambient reaction conditions yielded monomeric [CuII{(n-C4H9(C4H2S)CS2O}2] (3). 1 and 3 were authenticated by their single-crystal X-ray crystal structures. Crystal structure of 3 revealed cleavage of the S-S bond of 1 followed by insertion of O-atom, forming a new five-membered Cu–O–S–C–S metallacycle. 1, 2, and 3 were further investigated for their bioactivity through molecular docking with nine different proteins having medicinal implications. Molecular docking of 1, 2 and 3 revealed considerable interaction with different proteins viz. cancer protein Tankyrase 2, influenza viral protein Polymerase subunit PAC–PB1N complex (H5N1), Polymerase subunit PA endonuclease (H1N1), Polymerase subunit PAn Apo(avian influenza), and FTSZ (Bacillus subtilis). Comparatively, 1 has promising application in therapeutics as compared to 2 and 3 based on its inhibitory constant and binding energy. Density functional theory calculations were performed to better understand the bonding of complex using MO diagram in 1–3. Moreover, TDDFT calculations were performed to facilitate the assignment of electronic transitions of UV–Vis spectra.