University of Madras

About: University of Madras is a education organization based out in Chennai, Tamil Nadu, India. It is known for research contribution in the topics: Ring (chemistry) & Lipid peroxidation. The organization has 8496 authors who have published 11369 publications receiving 211152 citations. The organization is also known as: Madras University & University of Chennai.

Synthesis and characterization of nanoscale-hydroxyapatite-copper for antimicrobial activity towards bone tissue engineering applications.

Abstract: The bacterial infection is one of the major problems associated with implant and reconstructive surgery of bone. Hence, the aim of this study was to develop biomaterials having antibacterial activity for bone tissue engineering. The hydroxyapatite nanoparticles (nHAp) improve the mechanical properties and incorporate nanotopographic features that mimic the nanostructure of natural bone. We report here for the first time the synthesis and characterization of nHAp and nHAp soaked with copper (nHAp-Cu) using SEM, AFM, FTIR and XRD. The antibacterial activity of nHAp and nHAp-Cu was determined using Gram-positive and Gram-negative bacterial strains. To have accelerated antibacterial activity, polyethylene glycol 400 (PEG 400), a synthetic biodegradable polymer was also added along with nHAp-Cu. The nHAp-Cu/PEG 400 had increased antibacterial activity towards Gram-positive than Gram-negative bacterial strains. The cytotoxicity of nHAp-Cu/PEG 400 was determined using MTT assay with rat primary osteoprogenitor cells and these biomaterials were found to be non-toxic. Hence, based on these results we suggest that the biomaterials containing nHAp-Cu/PEG 400 can be used as antibacterial materials in bone implant and bone regenerative medicine.

Monodentate coordination of N-[di(phenyl/ethyl)carbamothioyl]benzamide ligands: synthesis, crystal structure and catalytic oxidation property of Cu(I) complexes.

Abstract: New four-coordinated tetrahedral copper(I) complexes have been synthesized from the reactions between [CuCl2(PPh3)2] and N-(diphenylcarbamothioyl)benzamide (HL1) or N-(diethylcarbamothioyl)benzamide (HL2) in benzene. These complexes have been characterized by elemental analyses, IR, UV/Vis, 1H, 13C and 31P NMR spectroscopy. The molecular structure of both the complexes, [CuCl(HL1)2(PPh3)] (1) and [CuCl(HL2)(PPh3)2] (2) were determined by single-crystal X-ray diffraction, which reveals distorted tetrahedral geometry around each Cu(I) ion. The combination of 2 (0.005 mmol) with hydrogen peroxide (2.5 mmol) in acetonitrile is found to be an active catalyst for the oxidation of primary and secondary alcohols (0.5 mmol) to their corresponding acids and ketones, respectively, at room temperature.

A novel fluorophore with dual fluorescence: local excited state and photoinduced electron-transfer-promoted charge-transfer state.

Abstract: Absorption and emission spectra of 9-N,N-dimethylaniline decahydroacridinedione (DMAADD) have been studied in different solvents. The fluorescence spectra of DMAADD are found to exhibit dual emission in aprotic solvents and single emission in protic solvents. The effect of solvent polarity and viscosity on the absorption and emission spectra has also been studied. The fluorescence excitation spectra of DMAADD monitored at both the emission bands are different. The presence of two different conformation of the same molecule in the ground state has lead to two close lying excited states, local excited (LE) and charge transfer (CT), and thereby results in the dual fluorescence of the dye. A CT state involving the N,N-dimethylaniline group and the decahydroacridinedione chromophore as donor and acceptor, respectively, has been identified as the source of the long wavelength anomalous fluorescence. The experimental studies were supported by ab initio time dependent-density functional theory (TD-DFT) calculations performed at the B3LYP/6–31G* level. The molecule possesses photoinduced electron transfer (PET) quenching in the LE state, which is confirmed by the fluorescence lifetime and fluorescent intensity enhancement in the presence of transition metal ions.