A Review of Approaches to the Metallic and Non-Metallic Synthesis of Benzimidazole (BnZ) and Their Derivatives for Biological Efficacy.

Heterocyclic compounds are significant lead drug candidates based on their various structure-activity relationships (SAR), and their use in pharmaceutics is constantly developing. Benzimidazole (BnZ) is synthesized by a condensation reaction between benzene and imidazole. The BnZ structure consists of two nitrogen atoms embedded in a five-membered imide ring which is fused with a benzene ring. This review examines the conventional and green synthesis of metallic and non-metallic BnZ and their derivatives, which have several potential SARs, along with a wide range of pharmacological properties, including anti-cancer, anti-inflammatory, anti-microbial, anti-tubercular, and anti-protozoal properties. These compounds have been proven by pharmacological investigations to be efficient against different strains of microbes. Therefore, in this review, the structural variations of BnZ are listed along with various applications, predominantly related to their biological activities.

Theoretical investigation of C1-C4 hydrocarbons adsorption and separation in a porous metallocavitand.

The purification of light hydrocarbons is one of the most important chemical processes globally which consumes substantial energy. Porous materials are likely to improve the efficiency of the separation process by acting as regenerable solid adsorbents. To investigate such translational systems, the underlying mechanism of adsorption in the porous materials must be taken into account. Herein we report the adsorption and selective separation of C1-C4 hydrocarbons in the coinage metal-based macrocyclic metallocavitand Pillarplex, which exhibits excellent performance in the adsorption of CH4 at the ambient conditions with a binding energy of -17.9 kcal mol-1. In addition, the endohedral adsorption of C2-C4 hydrocarbon is impressive. The CH4, C2H4, C3H4, and 1,3-butadiene have potential uptake of 2.57, 4.26, 3.60, and 2.95 mmol g-1, respectively at ambient conditions are highest from their respective isomers. Selective separation of C1-C4 hydrocarbons is studied using ideal adsorption solution theory demonstrating its potential for one-step purification of C1-C3 hydrocarbons.

Surface-Induced in Situ Sonothermodynamically Controlled Functionalized Graphene Oxide for in Vitro Cytotoxicity and Antioxidant Evaluations.

Graphene oxide-based advanced functional materials offer an ultimate solution for wider biomedical applications. In situ thermodynamically ultrasound-assisted direct covalent functionalization of graphene oxide (GO) with sulfanilamide (SA) has synthesized f-(SA)GO. Raman spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction pattern, scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) have analyzed the f-(SA)GO structure for functional activities, expressed through synergistic impact of heteroatomic domains (SIHAD). The TGA of GO and f-(SA)GO demonstrates their total weight losses of 82.0 and 61.1%, respectively. Enhanced thermal stability of f-(SA)GO infers an exothermic behavior obtained with DSC. The surface-induced in situ thermodynamically controlled nonspontaneous reaction for f-(SA)GO has facilitated calculations for activation energy (E a) = - 2.65 × 103 kJ mol-1 and Gibbs free energy (ΔG) = 8.3741 kJ mol-1, energetics for biological activities with sulforhodamine B assay on MCF-7 and Vero cell lines and antioxidant potential by free radical scavenging activity with DPPH (2,2-diphenyl-1-picrylhydrazyl). Cell viabilities are >89.8% for Vero and >90.1% for MCF-7 with f-(SA)GO over 10 to 80 µg mL-1. Its cytocompatibility infers establishment of a new material. The morphological effect on MCF-7 and Vero cell lines confirm its structurally stable biocompatibility. The SIHAD of f-(SA)GO scavenges radical activity, and its heteroatomic structure causes valuable physiochemical activities. f-(SA)GO could emerge as an advanced functional biomaterial for structurally and thermally stable biocompatible nanocoatings.

Sonochemically N-functionalized graphene oxide towards optically active photoluminescent bioscaffold.

Herein, Nitrogen functionalized graphene oxide (N-f-GrO) has been synthesized using the sonochemical method. 2-Aminopyrimidine (APD) was used as a precursor for covalent functionalization with graphene oxide [f-(APD)GrO] as N-f-GrO which was ascertained with XPS. The involvement of arylamine group and formation of covalent bond over GrO surface was confirmed with high resolution C1s spectrum of f-(APD)GrO. Also, the signature of N1s peak in the survey spectrum of f-(APD)GrO has endorsed the surface modification of GrO through covalent functionalization. A bathochromic shift was observed for f-(APD)GrO in UV and enhanced weight loss of 91.39% at 191.80 °C, confirms a facile functionalization of GrO via formation of amide bond, where the terminal -OH portal of carboxylic group is substituted by 2-Aminopyrimidine. Moreover, the formation of f-(APD)GrO was investigated with various analytical techniques like Raman, XRD and FTIR. The surface morphology and topography have been understood by using HRTEM/SAED, AFM, and SEM analysis. The synthesized f-(APD)GrO shows potential optically active photoluminescence properties and higher potency towards biological insight. The identified photoluminescence (PL) peaks at 3.78, 3.21 2.01 and 1.64 eV indicate photon emission including an orange optical transition at 2.01 eV. The multiple peaks in a PL spectrum are due to radiative and non-radiative recombinations which are also associated with excess hole (h+)-electron (e-) trapping on the surface to restrict the recombinations of e- and h+. The biological activity of N-f-GrO has been explored with Sulforhodamine B (SRB) assay on HaCaT and Vero cell lines. The concentration-dependent cell viabilities have been observed a maximum at 20 µg/ml for HaCaT and at 10 µg/ml for Vero cell lines at testing concentration range of 10-80 µg mL-1. The significant morphological impact on cell lines confirms the cytocompatibility behaviour. Therefore, the synergistic impact of various properties of f-(APD)GrO can be further explored to study its significance as nanocarrier for photosensitive biomedical response.

Dispersion enhancing effect of sonochemically functionalized graphene oxide for catalysing antioxidant efficacy of curcumin.

The non-hazardous sonochemical approach has been developed for the functionalization of graphene oxide (GrO) with 5-Aminoindazole (5-AIND). The formation of f-(5-AIND) GrO is confirmed with 13C solid state NMR, HRXPS, XRD, Raman, TGA, DSC, FTIR etc. The >80% cell viabilities on MCF-7 and Vero cell lines have confirmed the high cytocompatibility of f-(5-AIND) GrO. Additionally, the morphological impact on Vero cell line has evidently confirmed the biocompatibility of f-(5-AIND) GrO. As compared to GrO, the f-(5-AIND) GrO has demonstrated an enhanced antioxidant efficacy of 69.4-72%, evaluated with 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay. With a similar objective (0.01-0.05)mL peanut oil based curcumin micro and nanoemulsions have been prepared using ethanol and glycerol as co-solvent and co-surfactant respectively. The prepared emulsions are subsequently characterised with respect to morphological and physicochemical parameters via density, surface tension, viscosity, friccohesity measurement and DLS analysis. Henceforth, with an expectation to achieve higher dispersion, an ethanolic dispersion of f-(5-AIND) GrO has been mixed with curcumin carrying emulsions in 1:1. Notably, the radical scavenging activities (RSA) of the combined formulations are significantly enhanced to an extent of 26.6%.

In situ sonochemical reduction and direct functionalization of graphene oxide: A robust approach with thermal and biomedical applications.

The rapid, robust, scalable and non-hazardous sonochemical approach for in situ reduction and direct functionalization of graphene oxide has been developed for non-toxic biomedical applications. The graphene oxide (GrO) was directly functionalized with tryptamine (TA) without using any hazardous acylating and coupling reagents. The reaction was completed within 20min. An impact of ultrasound was inferred for a direct functionalization with other conventional methods. The evolved electronic states were confirmed with near edge X-ray absorption fine structure (NEXAFS). The direct covalent functionalization and formation of f-(TA) GrO was proven with FTIR, 13C solid state NMR, XPS, XRD, Raman' HRTEM, AFM and TGA. The total percentage weight loss in TGA confirms an enhanced thermal stability of f-(TA) GrO. The f-(TA) GrO was further explored for an investigation of in vitro antimicrobial activity to ensure the health and environmental safety. An outstanding antibacterial activity of f-(TA) GrO was found against gram positive Staphylococcus aureus at MIC 128mgmL-1. It confirms a suitability of f-(TA) GrO for thermally stable antibacterial coating. The f-(TA) GrO showed 39.14-48.9% antioxidant activities, evaluated with 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay. The inherent cytotoxicity of f-(TA) GrO was evaluated with SRB assay to living cells, MCF-7 and Vero. The estimated cell viabilities were >80% upon addition of f-(TA) GrO over a wide concentration range of 10-80µgmL-1. The high cytocompatibility of f-(TA) GrO confirms the low toxicity and an excellent biocompatibility. The morphological effect on Vero cell line, evidently confirmed the biocompatibility of f-(TA) GrO. Therefore, f-(TA) GrO was emerged as an advanced functional biomaterial for thermal and biomedical applications.

Ultrasound assisted simultaneous reduction and direct functionalization of graphene oxide with thermal and cytotoxicity profile.

The new sonochemical approach for simultaneous reduction and direct functionalization of graphene oxide (GrO) has been developed. The GrO was functionalized with 2-Aminobenzoxazole (2-ABOZ) in twenty min with complete deletion of hazardous steps. The significance of ultrasound was exemplified with the comparative conventional methods. The newly prepared f-(2-ABOZ)GrO was extensively characterized with near edge X-ray absorption fine structure (NEXAFS) spectroscopy, 13C solid state NMR, XPS, XRD, HRTEM, SAED, AFM, Raman, UV-vis, FTIR and TGA. The thermal stability of f-(2-ABOZ)GrO was confirmed with total percentage weight loss in TGA. The biological activity of f-(2-ABOZ)GrO was explored with MCF-7 and Vero cell lines. The inherent cytotoxicity was evaluated with SRB assay at 10, 20, 40 and 80µgmL-1. The estimated cell viabilities were >78% with f-(2-ABOZ) GrO. A high cytocompatibility of f-(2-ABOZ)GrO was ensured with in vitro evaluation on living cell lines, and low toxicity of f-(2-ABOZ)GrO was confirmed its excellent biocompatibility. The morphological effect on Vero cell line evidently supports the formation of biocompatible f-(2-ABOZ)GrO. Therefore, f-(2-ABOZ)GrO was emerged as an advanced functional material for thermally stable biocompatible coatings.