Spectral characterization of tetradentate Schiff base complexes of N2O2 donor groups

200-206Copper(II) complexes of tetradentate Schiff bases N, N’–disalicylidene–1, 2–phenylenediamine(H2dsp), N, N’–disalicylidene–3, 4–diaminotoluene(H2dst), 4–nitro-N, N’–disalicylidene–1, 2–phenylenediamine(H2ndsp), N, N’–disalicylideneethylenediamine(H2salen) have been synthesized and characterized by elemental analysis, electronic spectra, IR spectra, magnetic susceptibility measurement, EPR, CV and thermal studies. TG studies show that Cu(dsp) and Cu(ndsp) complexes thermally degrade in two steps and Cu(dst) and Cu(salen) in one step. Kinetic and thermodynamic parameters have been computed from thermal decomposition data. The activation energies of both the thermal degradation step is found to lie in between 52–74 kJ mol−1

An Extensive Assessment of Ambient Air Quality In City Delhi: Air Quality Monitoring, Source Apportionment And Analysis

The Analysis of air quality data for three consecutive years 2018, 2019 and 2020 showed that there was a significant reduction in the concentration of almost all pollutants in year 2020 except for ozone and benzene. In 2020 the decrease in concentration may be observed due to various restrictions imposed during lockdown called due to COVID 19 pandemic. A relative reduction of 35.38% in PM10, 38.79% in PM2.5, 23.90% in NO2, 8.22% in SO2 , 17.64% in CO, 22.36% in NO and 9.98% in NH3 have been observed in 2020 when compared to 2019. Correlation and p-value analysis indicates that there is significant correlation between some of the pollutant pairs but the same pattern is not retained over time. The Principal component analysis (PCA) reflects that only first four principal components are significant, which identifies the pollution caused due to vehicles as primary and major source of air pollution in Delhi. Regional atmospheric transfer of pollutants from nearby areas from burning of agricultural waste, coal etc. were found to be the secondary major source of air pollution in Delhi. The objective of the present work is to analyze the distribution of eleven major pollutants namely particulate matters (PM10 and PM2.5), nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3), nitric oxide (NO), oxides of nitrogen (NOx), ammonia (NH3), carbon monoxide (CO), benzene (C6H6), toluene along with meteorological parameters, air temperature (AT), wind speed (WS), wind direction (WD), barometric pressure (BP), solar radiation (SR) and relative humidity (RH) in the mega city Delhi for the three consecutive years 2018, 2019 and 2020

Novel Papaverine Metal Complexes with Potential Anticancer Activities

Cancer is one of the leading causes of death worldwide. Although several potential therapeutic agents have been developed to efficiently treat cancer, some side effects can occur simultaneously. Papaverine, a non-narcotic opium alkaloid, is a potential anticancer drug that showed selective antitumor activity in various tumor cells. Recent studies have demonstrated that metal complexes improve the biological activity of the parent bioactive ligands. Based on those facts, herein we describe the synthesis of novel papaverine–vanadium(III), ruthenium(III) and gold(III) metal complexes aiming at enhancing the biological activity of papaverine drug. The structures of the synthesized complexes were characterized by various spectroscopic methods (IR, UV–Vis, NMR, TGA, XRD, SEM). The anticancer activity of synthesized metal complexes was evaluated in vitro against two types of cancer cell lines: human breast cancer MCF-7 cells and hepatocellular carcinoma HepG-2 cells. The results revealed that papaverine-Au(III) complex, among the synthesized complexes, possess potential antimicrobial and anticancer activities. Interestingly, the anticancer activity of papaverine–Au(III) complex against the examined cancer cell lines was higher than that of the papaverine alone, which indicates that Au-metal complexation improved the anticancer activity of the parent drug. Additionally, the Au complex showed anticancer activity against the breast cancer MCF-7 cells better than that of cisplatin. The biocompatibility experiments showed that Au complex is less toxic than the papaverine drug alone with IC50 ≈ 111 µg/mL. These results indicate that papaverine–Au(III) complex is a promising anticancer complex-drug which would make it a suitable candidate for further in vivo investigations.Peer Reviewe

Synthesis, spectroscopic characterizations and DFT studies on the metal complexes of azathioprine immunosuppressive drug

ABSTRACT. A complex of the immunosuppressive drug azathioprine with Cr(II), Mn(II), Fe(II), Zn(II), Cu(II), Ni(II), and Co(II) were synthesized and characterized through spectroscopic and thermal studies. The infrared spectra show the coordination of azathioprine via N(9) to the metal, also, the range around 640–650 cm−1 remains unchanged in the complexes, indicating the possibility that the ether group may not be involved in the binding. Thermogravimetric analysis (TG), thermogravimetric derivational analysis (DTG), and differential thermogravimetric analysis (DTA) have been studied in the temperature range from 0 °C to 1000 °C. The study of pyrolysis showed that all complexes decompose in more than one step and that the final decomposition product is metal oxide. The DFT (density functional theory) with B3LYP/6-31G++ level of theory was used to study the optimized geometry, HOMO→LUMO energy gap, and molecular electrostatic potential map of azathioprine before and after deprotonation.                 KEY WORDS: Azathioprine, Spectral study, Thermal study, Decomposition products, DFT Bull. Chem. Soc. Ethiop. 2022, 36(1), 73-84.                                                                   DOI: https://dx.doi.org/10.4314/bcse.v36i1.

Solid phase extraction of lead using modified cellulose in natural, wastewater and egg samples

413-4182-Pyridyliminosalicylcellulose has been used for the sorption and estimation of lead(II) by column and batch techniques. The distribution coefficient (D) was found to be 4.3102 for the lead ion. The detection limit was found to be 3.82 ng mL-1 and the breakthrough volume was 20 mL. The present matrix coupled with FAAS has been used to enrich and determine the lead ions in natural and wastewater (RSD ~ 2.52-3.50%) and egg samples (RSD ~ 2.73%). The method is simple, rapid and relatively free from interference and satisfactorily applied for the estimation of lead (~98% recovery) in natural, wastewater and egg samples

Spectral and thermal characterization of new biomimetic polydentate amide ligands

1106-1108Complexes of manganese(II) and nickel(II) with N,N'- bis(3- carboxy-1 -oxopropanyl)- 1, 2-ethylenediamine (C10H16N2O6,L1) N,N'- bis(3-carboxy-1 -oxopropanyl)- 1,  2-phenylediamine (C14H16 N2O6,L2),  N,N'- bis(3-carboxy-1 -oxophenelenyl)- 1 , 2- phenylenediamine (C22H16, N2O6,L3)and N,N'- bis(3-carboxy-1- oxoprop- 2-enyl)-1, 2-phenylenediamine (C14H12N2O6, L4) have been prepared and characterized by elemental analysis, vibrational spectra, magnetic susceptibility measurements, electronic spectra and thermal studies. Vibrational spectra indicates coordination of amide and carboxylate oxygens of the ligands giving a MO4 chromophore. Electronic spectra support square planar geometry around nickel(II) and tetrahedral around manganese(II). NiL1 complex has the maximum activation energy and NiL2 complex has the minimum activation energy

Micellar spectrofluorimetric determination of lead(II) in natural water, waste water and egg samples with N-(2ʹ-pyridyl)- 2-hydroxybenzamide

1410-1412A sensitive, convenient and rapid spectrofluorimetric method for determination of lead(II) with N-(2'-pyridyl)-2-hydroxybenzamide in a Brij-35 micellar medium has been developed. The calibration graph is linear over the range 0.2-2 μg/ml Pb(II) with regression coefficient of 0.9997 and relative standard deviation 2.9%. The method is relatively free from interference and satisfactorily applied for the determination of lead(II) in natural, waste water and egg samples

Chemical speciation and biological activity of bivalent metal complexes of polydentate amide ligands

275-279Stability constants of N,N'-bis-(3-carboxy-l-oxopropanyl)-1,2-ethylenediamine(L1), N,N'-bis-(3-carboxy-l-oxopropanyl)- 1,2-phenylenediamine(L2), N,N' -bis-(2-carboxy-l-oxophenelenyl)-1,2-phenylenediamine(L3) have been determined in aqueous medium (for L1 & L2) and 75% (v/v) m ethanol-water medium for L3 pH-metrically. The formation constants (logβn) have been calculated using the Bjerrum half integral method and weighted least squares method. Species distribution curves of complexes have been plotted as a function of pH which shows at lower pH values 1: 1 complexes are formed and 1:2 complexes are formed at neutral or higher pH. The biological study indicates that ligands and their complexes are better fungicidal than bactericidal. Copper complexes of all the ligands showed potential antifungal and antibacterial activities. Ligand L3 and its copper(II) complexes are most effective against A. niger. E. coli and S. aureus.</i

Spectral and thermal studies of homodinuclear and heterodinuclear glutathione complexes

1205-1207The complexes of the types [M2LSO4.2H2O] where L=GSH, M = Co(II), Cu(II), Zn(II), Cd(II) and [MM'LSO4.2H2O] where L = GSH, M = Cu(II), M' = Zn(II) and M = Co(II), M' = Cd(II)] have been prepared and characterized by elemental analysis, magnetic susceptibility measurements, JR, EPR, electronic spectral studies and thermal analysis. Deprotonation and coordination of thiol group occurs and glycine residue binds with the metal ions in all the complexes. Copper(II) and cobalt(II) complexes show low magnetic moment. EPR spectral data show that complexes have planar geometry. Ligand to metal charge transfer are observed in all the complexes and d-d transition are also observed in copper(II) and cobalt(II) complexes. Thermal decomposition of all the complexes proceeds via first order kinetics