Search

The present study attempted to demonstrate the potential application of Kraft lignin (KL) from sugarcane baggasse biomass in the bio-therapeutic areas. Novel conjugate materials (Dex-ald–KL and BSA–KL) were synthesized incorporating KL into dextran aldehyde (Dex-ald) and bovine serum albumin (BSA) via a free radical reaction involving reactive oxygen species induced by ascorbic acid/H2O2 redox pair and studied using various physico-chemical techniques. UV–Visible spectral analysis of the resulting conjugates proved the enhanced conjugation (matrix formation) between constituent biopolymers due to formation of intermolecular linkages. Visual changes were observed in the X-ray diffractogram (XRD) peaks of the conjugates in comparison to free components. Cell viability of the novel conjugate materials was found to decrease by ~ 55–61% against colon cancerous cells (SW480) proving its efficacy as anti-cancer agent while the quantity of reactive oxygen species (ROS) level markedly increased on treatment with conjugate material in comparison to Dex-ald, KL and BSA alone. The above evidences indicated that the conjugates with even low amounts of lignin incorporation exhibited remarkable cytotoxicity suggesting their practical use in the treatment of certain type of cancers.

A novel ruthenium metalated complex has been synthesized by co-ordinating bipyridyl molecules and 4-aryl substituted thiosemicarbazide N-(4-nitrophenyl)hydrazinecarbothioamide ligand to ruthenium(II) metal center.Phosphotungstic acid (H3PW12O40) was used to immobilize the ruthenium complex [Ru(bpy)2(4-(p-NO2)C6H4TA)](ClO4)2 by solvothermal method, thus producing an organic-inorganic hybrid. The [Ru(bpy)2(4-(p-NO2)C6H4TA)](ClO4)2 and organic-inorganic hybrid [Ru(bpy)2(4-(p-NO2)C6H4TA)][HPW12O40] were characterized by elemental analysis, FT-IR,powder-XRD and DRUV-Vis. The change in surface morphology after the formation of hybrid from metal complex was investigated by SEM images. EDX analysis of hybrid [Ru(bpy)2(4-(p-NO2)C6H4TA)][HPW12O40] has shown that the monomeric unit of [Ru(bpy)2(4-(p-NO2)C6H4TA)](ClO4)2 has combined with [H3PW12O40] Keggin unit. Molecular formula of the hybrid was auxiliary confirmed by Inductively Coupled Plasma (ICP) technique. Both the metal complex and the hybrid are studied for oxidative catalytic conversion of alkyl aromatic and cycloalcohols. [Ru(bpy)2(4-(p-NO2)C6H4TA)][HPW12O40] has exhibited better catalytic activity in terms of selectivity and conversion percentage as compared to [Ru(bpy)2(4-(p-NO2)C6H4TA)](ClO4)2. Ru(bpy)2 (4-(p-NO2)C6H4TA)][HPW12O40] was reused multiple times. The products formed during catalysis were identified by mass spectroscopy and gas chromatography.

O-Carboxymethyl chitosan (OCMC) Schiff’s base was utilized for a new class of organic-inorganic hybrid material by grafting it on nano-silica-silane and further metallated with Cu (II). Here (3-Aminopropyl) triethoxysilane (APTES) was used as a linker and 2-hydroxy-1-naphthaldehyde (HN) for Schiff’s base formation. The hybrid was characterized by FTIR, TGA, powder XRD, SEM, CHN, DLS, ICP-AES, diffuse reflectance UV–vis and EDX spectroscopic techniques. Magnetization measurements were carried out by VSM at room temperature. This study explored the possible synergic effect of unique properties of carboxymethyl chitosan, Schiff’s base Cu (II) complex and nano-silica towards antibacterial activity and in dye degradation studies. The antibacterial performance of nano-hybrid material was examined against both Gram-positive (Escherichia coli) and Gram-negative (Bacillus subtilis) bacteria. The catalytic activity of the hybrid was tested for degradation of reactive black 5 (RB5) through advanced oxidation processes using H2O2 as oxidant. The results show a high dye degradation efficiency of 93% in 130 min by the hybrid catalyst with reusability. As per published reports, Chitosan-Schiff’s bases show strong antimicrobial activity and their Cu complexes exhibit good catalytic and anticancer activities. Therefore, it is expected that the new organic-inorganic hybrid would be highly applicable in environmental as well as biomedical fields.

A series of new hybrids, POM (M-Salen@POM) were synthesized by successfully inserting metallosalen compounds (where M ​= ​Co, Cu, Fe and Ru) into the lacunary position of Keggin type polyoxometalate, K8SiW11O39 (POM). The hybrids were characterized by FT-IR, powder XRD, diffuse reflectance UV–Vis, energy dispersive X-Ray and inductively coupled plasma atomic emission spectroscopy (ICP) techniques. The hybrids with different metal centers were comparatively studied for their catalytic activity in the oxidation of cycloalkanes, cycloalcohols and alkyl aromatic using a green oxidant, hydrogen peroxide. The products obtained during catalysis were estimated by gas chromatography(GC) and mass spectroscopy(MS). Catalytically synthesized products are of high industrial importance.

An easy-to-prepare colorimetric and ON–OFF–ON fluorescent naphthol derivative 1 has been synthesized and characterized for sequential detection of Cu2+ and cysteine. Chemosensor 1 detects Cu2+ selectively in DMSO/H2O (3 : 7 v/v) by changing its UV-visible spectrum and color (colorless to yellow), leading to the formation of 1-Cu(II) complex. The resultant 1-Cu(II) complex recognizes cysteine (Cys) and the solution turns colorless with regeneration of the absorption band of 1. The detection limit of 1 for Cu2+ ion is found to be 0.27 μM, which is much lower than that recommended by WHO for drinking water (30 μM). Cu2+ ion exhibits quenching of the fluorescence intensity of 1, which is restored upon the addition of cysteine. Chemosensor 1 is used as an imaging reagent for detection of the cellular uptake of Cu2+ ion in A549 cell line (human lung carcinoma cell).