56 research outputs found
Synthesis, characterization and antimicrobial studies of organotin(IV) complexes of N-methyl-N-phenyldithiocarbamate
No full textOrganotin(IV) dithiocarbamate complexes have shown a large spectrum of biological activities, which includes antioxidants, anti-inflammatory, antimicrobial, antituberculosis, anticancer and antiviral. In this report, organotin(IV) dithiocarbamate complexes derived from N-methyl-N-phenyldithiocarbamate (L) and organotin have been synthesized. The complexes which were represented as C4H9(Cl)SnL2 (1), C6H5(Cl)SnL2 (2), (CH3)2SnL2 (3), (C4H9)2SnL2 (4) and (C6H5)2SnL2 (5), were characterized by spectroscopic techniques (FTIR, 1H, 13C and 119Sn NMR), elemental and thermal analyses (TGA and DTG). The structures of complexes (3) and (4) were further established by X-ray single crystal diffraction. The structures, in both complexes, gave a distorted octahedral geometry around the tin center. This is due to the longer bond length of one of the SnS bonds within the complexes compared to others, and also the electronic and steric demands caused by the alkyl substituents on the tin atom. The complexes exhibited varied antimicrobial activity against S. Aureus, B. cerues, K. pneumonia, P. aeruginosa, E. coli, C. albican and A. flavus. Complex 5 displayed the best antimicrobial activities compared to the other organotin complexes, and this could be attributed to the planar phenyl group attached to the tin center causing an increase in the lipophilicity of the complex through the lipid bilayer of the bacteria organism
On the estimation of the black-capped vireo (Vireo atricapillus) territory density using geographic information systems technology, 1996
No full textThis study is based on a 1994 survey of the nesting and territory preferences of the black-capped vireo, a small migratory songbird, within Fort Hood, Texas. By Federal Government Order 51 FR 44808-44812 of 1987 (Tazik et al., 1992), these birds were declared an endangered species based on a series of studies by J. D. Cornelius in 1985 and 1986 (Tazik et al., 1993). In this study, it has been shown that the vireo nesting and territory preferences are not uniform across Fort Hood installation grounds, rather the preference is towards the north to northwest. The vegetation in this region consists of oak woodlands, with grassy undergrowth; the elevation is at most 260 meters above sea level; and the geology yields loose and chalky limestone. In addition, the territory intensity, ?ij(s), for each point s(x,y) in the ijth grid cell on the military installation, has been estimated. For each such grid cell, the probability of a successful territory is given by Geographic Information Systems (GIS) raster color maps of territory distribution of the vireo have been produced. These maps were overlaid on the slope, aspect, soils, elevation, vegetation, and military activities coverages. With the density estimate of nesting success and the GIS maps, territory position preferences were identified, thus, helping in the Land Management Plan for the preservation of the black-capped vireo on the Fort Hood Military Installation
Organotin(IV) Dithiocarbamate Complexes: Chemistry and Biological Activity
No full textSignificant attention has been given to organotin(IV) dithiocabamate compounds in recent times. This is due to their ability to stabilize specific stereochemistry in their complexes, and their diverse application in agriculture, biology, catalysis and as single source precursors for tin sulfide nanoparticles. These complexes have good coordination chemistry, stability and diverse molecular structures which, thus, prompt their wide range of biological activities. Their unique stereo-electronic properties underline their relevance in the area of medicinal chemistry. Organotin(IV) dithiocabamate compounds owe their functionalities and usefulness to the individual properties of the organotin(IV) and the dithiocarbamate moieties present within the molecule. These individual properties create a synergy of action in the hybrid complex, prompting an enhanced biological activity. In this review, we discuss the chemistry of organotin(IV) dithiocarbamate complexes that accounts for their relevance in biology and medicine
In Vitro Cytotoxicity and Antioxidant Studies of Dovyallis caffra-Mediated Cassiterite (SnO2) Nanoparticles
No full textMany medicinal plants found in Africa, such as Dovyallis caffra, have been reported to contain various bioactive compounds, which have been found to reduce metal salts into their corresponding metal-based nanoparticles. In this paper, the evaluation of synthesis, characterization, and biological properties of Dovyallis caffra-mediated cassiterite (SnO2) nanoparticles was carried out. The physicochemical properties of the synthesized material were investigated using X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The characterization studies revealed that the material possessed a single tetragonal cassiterite SnO2 phase, having a cluster-like foam appearance and an irregular spherical morphology with diameters ranging from 6.57 to 34.03 nm. The biological screening revealed that the prepared cassiterite (SnO2) nanoparticles exhibited cytotoxicity against the MCF-7 breast cancer cells, with an IC50 value of 62.33 µg mL−1, better than the standard drug 5-fluorouracil, with an IC50 value of 71.21 µg mL−1. The radical scavenging potential of the nanoparticles, using the DPPH assay, showed that it possessed a slightly better activity than ascorbic acid, a common antioxidant. These results suggest that the Dovyallis caffra-mediated cassiterite (SnO2) nanoparticles possess the potential to simultaneously generate and scavenge excess ROS, which in turn results in the exhibition of good cytotoxicity and antioxidant properties
Metal-Based Nanoparticles in Food Packaging and Coating Technologies: A Review
No full textFood security has continued to be a topic of interest in our world due to the increasing demand for food. Many technologies have been adopted to enhance food supply and narrow the demand gap. Thus, the attempt to use nanotechnology to improve food security and increase supply has emerged due to the severe shortcomings of conventional technologies, which have made them insufficient to cater to the continuous demand for food products. Hence, nanoparticles have been identified to play a major role in areas involving food production, protection, and shelf-life extensions. Specifically, metal-based nanoparticles have been singled out to play an important role in manufacturing materials with outstanding properties, which can help increase the shelf-life of different food materials. The physicochemical and biological properties of metal-based nanoparticles, such as the large surface area and antimicrobial properties, have made them suitable and adequately useful, not just as a regular packaging material but as a functional material upon incorporation into biopolymer matrices. These, amongst many other reasons, have led to their wide synthesis and applications, even though their methods of preparation and risk evaluation remain a topic of concern. This review, therefore, briefly explores the available synthetic methods, physicochemical properties, roles, and biological properties of metal-based nanoparticles for food packaging. Furthermore, the associated limitations, alongside quality and safety considerations, of these materials were summarily explored. Although this area of research continues to garner attention, this review showed that metal-based nanoparticles possess great potential to be a leading material for food packaging if the problem of migration and toxicity can be effectively modulated
SnS2 and SnO2 Nanoparticles Obtained from Organotin(IV) Dithiocarbamate Complex and Their Photocatalytic Activities on Methylene Blue
No full textThis work reports the photocatalytic degradation of methylene blue (MB) dye using SnS2 and SnO2 nanoparticles obtained from a solvothermal decomposition (in oleylamine) and pyrolysis (in a furnace) processes, respectively, of the diphenyltin(IV) p-methylphenyldithiocarbamate complex. The complex, which was used as a single-source precursor and represented as [(C6H5)2Sn(L)2] (L = p-methylphenyldithiocarbamato), was synthesized and characterized using various spectroscopic techniques and elemental analysis. The structural properties and morphology of the as-synthesized nanoparticles were studied using X-ray diffraction (XRD) technique and transmission electron microscopy (TEM). UV-visible spectroscopy was used to study the optical property. The hexagonal phase of SnS2 and tetragonal SnO2 nanoparticles were identified, which exhibited varying sizes of hexagonal platelets and rod-like morphologies, respectively. The direct band gap energies of both materials, estimated from their absorption spectra, were 2.31 and 3.79 eV for SnS2 and SnO2, respectively. The photocatalytic performances of the SnS2 and SnO2 nanoparticle, studied using methylene blue (MB) as a model dye pollutant under light irradiation, showed that SnO2 nanoparticles exhibited a degradation efficiency of 48.33% after 120 min reaction, while the SnS2 nanoparticles showed an efficiency of 62.42% after the same duration of time. The higher efficiency of SnS2 compared to the SnO2 nanoparticles may be attributed to the difference in the structural properties, morphology and nature of the material’s band gap energy
Chemistry and Some Biological Potential of Bismuth and Antimony Dithiocarbamate Complexes
No full textInterest in the synthesis of Bi(III) and Sb(III) dithiocarbamate complexes is on the rise, and this has been attributed to their wide structural diversity and their interesting application as biological agents and in solid state/materials chemistry. The readily available binding sites of the two sulphur atoms within the dithiocarbamate moiety in the complexes confers a wide variety of geometry and interactions that often leads to supramolecular assemblies. Although none of the bismuth or antimony metals are known to play any natural biological function, their dithiocarbamate complexes, however, have proven very useful as antibacterial, antileishmanial, anticancer, and antifungal agents. The dithiocarbamate ligands modulate the associated toxicity of the metals, especially antimony, since bismuth is known to be benign, allowing the metal ion to get to the targeted sites; hence, making it less available for side and other damaging reactions. This review presents a concise chemistry and some known biological potentials of their trivalent dithiocarbamate complexes
PbS Nanoparticles Prepared Using 1, 10-Phenanthroline Adduct of Lead(II) Bis(N-alkyl-N-phenyl dithiocarbamate) as Single Source Precursors
No full textDithiocarbamate complexes have remained prominent as single source precursors for the synthesis of clean metal sulfide nanoparticles. This study reports the synthesis of lead sulfide (PbS) nanoparticles using some novel complexes of 1, 10-phenanthroline lead(II) bis(N-alkyl-N-phenyl dithiocarbamate), represented as [Pb(L1)2phen] (1) and [Pb(L2)2phen] (2) (where L1 = bis(N-ethyl-N-phenyldithiocarbamate; L2 = bis(N-butyl-N-phenyldithiocarbamate); phen = 1, 10 phenanthroline) as a single source precursors. The complexes (1 and 2) were synthesized and characterized using various spectroscopic techniques and elemental analysis. The nanoparticles were synthesized via a solvothermal approach in oleylamine, used as a capping agent, and were given as PbS(1) and PbS(2) from [Pb(L1)2phen] (1) and [Pb(L2)2phen] (2), respectively, which were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and absorption spectroscopy. The diffraction patterns confirmed the formation of face-centered cubic phase PbS nanoparticles with a preferential growth orientation along the (200) plane. The TEM images showed that PbS(1) were of a spherical morphology, while the morphology of PbS(2) tended to produce short rods. This was due to variation in the functional group on the precursor compounds. This variation also resulted in the different band gap energies found such as 1.148 and 1.107 eV for PbS(1) and PbS(2), respectively, indicating a blue shift from the bulk
Biogenic Synthesis of CuO, ZnO, and CuO–ZnO Nanoparticles Using Leaf Extracts of Dovyalis caffra and Their Biological Properties
No full textBiogenic metal oxide nanoparticles (NPs) have emerged as a useful tool in biology due to their biocompatibility properties with most biological systems. In this study, we report the synthesis of copper oxide (CuO), zinc oxide (ZnO) nanoparticles (NPs), and their nanocomposite (CuO–ZnO) prepared using the phytochemical extracts from the leaves of Dovyalis caffra (kei apple). The physicochemical properties of these nanomaterials were established using some characterization techniques including X-ray diffraction analysis (XRD), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The XRD result confirmed the presence of a monoclinic CuO (Tenorite), and a hexagonal ZnO (Zincite) nanoparticles phase, which were both confirmed in the CuO–ZnO composite. The electron microscopy of the CuO–ZnO, CuO, and ZnO NPs showed a mixture of nano-scale sizes and spherical/short-rod morphologies, with some agglomeration. In the constituent’s analysis (EDX), no unwanted peak was found, which showed the absence of impurities. Antioxidant properties of the nanoparticles was studied, which confirmed that CuO–ZnO nanocomposite exhibited better scavenging potential than the individual metal oxide nanoparticles (CuO, and ZnO), and ascorbic acid with respect to their minimum inhibitory concentration (IC(50)) values. Similarly, the in vitro anticancer studies using MCF7 breast cancer cell lines indicated a concentration-dependent profile with the CuO–ZnO nanocomposite having the best activity over the respective metal oxides, but slightly lower than the standard 5-Fluorouracil drug
Synthesis, theoretical calculation, and biological studies of mono- and diphenyltin(iv) complexes of n-methyl-n-hydroxyethyldithiocarbamate
No full textIn this study, chlorophenyltin(IV) [(C6H5)(Cl)Sn(L)2] and diphenyltin(IV) [(C6H5)2Sn(L)2]
of N-methyl-N-hydroxyethyldithiocarbamate were prepared and characterized using various spectroscopic
methods (FTIR, 1H, 13C, and 119Sn NMR) and elemental analysis. The FTIR and NMR
spectral data, used to establish the structure of the compounds, showed the formation of the complexes
via coordination to the two sulfur atoms from the dithiocarbamate ligand and the respective
phenyltin(IV) derivatives. This coordination mode was further explored by DFT calculations, which
showed that the bonding around the Sn center in [(C6H5)2Sn(L)2] was more asymmetric compared
to the bonding around [(C6H5)(Cl)Sn(L)2]. However, the Sn–S bonds in [(C6H5)(Cl)Sn(L)2] were
found to be more covalent than those in [(C6H5)2Sn(L)2]
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