126 research outputs found
Square-planar copper(II) complexes with tetradentate amido-carboxylate ligands. Crystal structure of Na2[Cu(obap)]2.H2O. Strain and spectral assignments of complexes
No full textNovel N–N–N–O-type of tetradentate ligands H3obap (H3obap = oxamido-N-aminopropyl-N0-benzoic acid) and H3maeb
(H3maeb = malamido-N-aminoethyl-N0-benzoic acid) and the corresponding square-planar copper(II) complexes have been prepared
and characterized. The obap3 and maeb3 ligands coordinate to the copper(II) ion via four ligating atoms (three deprotonated
atoms: one carboxylate oxygen and two deprotonated amide nitrogens; one amine nitrogen) with in-plane square chelation. A
four coordinate, square-planar geometry has been established crystallographically for the binuclear Na2[Cu(obap)]2 Æ 2H2O complex.
Structural data correlating the square-planar geometry of the [Cu(obap)] unit and an extensive strain analysis are discussed
in relation to the information obtained for similar complexes. The infrared and electronic absorption spectra of the complexes are
discussed in comparison to the related complexes of known geometries. Antibacterial activity of ligands and copper(II) complexes
towards common Gram-negative and Gram-positive bacteria are reported as well
Structural, biological and computational study of oxamide derivative|СТРУКТУРНА, БИОЛОШКА И РАЧУНСКА ИПИТИВАЊА ДЕРИВАТА ОКСАМИДА
No full textA dicarboxylato-diamide-type compound 2,2'-[(1,2-dioxoethane-1,2--diyl)diimino]dibenzoicacid (H(4)obbz) (1) was synthesized and characterized. The crystal structure of K(2)H(2)obbz center dot 2H(2)O (2) was determined by X-ray diffract-tion analysis. The cytotoxic activities of the compounds were tested against four different cancer cell lines MCF-7, A549, HT-29, HeLa and a human nor-mal cell line MRC-5. The results indicate reasonable dose-dependent cytotox-icity of the ligands that show selectivity against the tested carcinoma and healthy cell lines. Flow cytometric analysis and fluorescence microscopy showed that the most active compound, H(4)obbz, induced apoptosis and G0/G1 cell cycle arrest, indicating blockage of DNA synthesis as a possible mechanism that trig-gers apoptosis. Docking and molecular dynamics simulations gave similar res-ponses regarding interactions (binding) between their ligands and chaperon Grp78. The MMGBSA determined Delta G binding energies were in the range from -104 to -140 kJ mol(-1)
Square Planar copper(II) complexes with a novel tetradentate amido- carboxilate ligand. Crystal structure of [Co(H2O)6][Cu(mda)]2H2O
No full textCharacterization of two geometrical isomers of (1,3-propanediamine-N,N'-diacetato-N,N'-di-3-propionato)nickelate(II). X-ray structure of the binuclear complex trans(O5)-[Ni2(1,3pddadp)(H2O)4].4H2O and octahedral distortion of edta-type chelates
No full textRhodium(III) in a cage of the 1,3-propanediamine-N,N,N′-triacetate chelate: X-ray structure, solution equilibria, computational study and biological behavior
No full textTwo new octahedral Rh(III) complexes that are potential chemotherapeutic agents have been synthesized from the 1,3-propanediamine-N,N,N’-triacetate ligand (1,3-pd3a): [Rh(1,3-pd3a)(H2O)]·2H2O (1) and Na[Rh(1,3-pd3a)Cl]·2H2O (2). Both complexes were characterized by IR, UV–Vis and NMR spectroscopy, as well as elemental analysis. Only the structure of 2 was determined by a single crystal X-ray diffraction study. The asymmetric unit contains the negatively charged rhodium complex, a sodium ion and two water molecules. The positions of the carboxylate groups define the cis-polar geometry. DFT calculations on 1 and 2 have also been done to confirm experimental results. In order to determine the protonation constants of 1,3-H3pd3a, stability constants and the stoichiometry of the complexes in aqueous solution, pH-potentiometry and UV–Vis spectrophotometry were used. Docking of 1 to human serum albumin (HSA) gives the reasonable assumption that this complex can be easily transported to the target cells. The complexes, as well as the 1,3-pd3a and ed3a ligands, were tested against various cancer and one normal human cell lines. Complex 2 and both ligands display significant cytotoxicity against the HeLa cancer cell line, while 1 shows good antitumor activity against MCF-7. Flow cytometry analysis showed the apoptotic death of the cells with cell cycle arrest in the G2/M phase (Na[Rh(1,3-pd3a)Cl]·2H2O) and G0/G1 phase (1,3-pd3a)
Plant Biomass Productivity Under Abiotic Stresses in SAT Agriculture
No full textThe semi-arid tropics (SAT) include parts of 48 countries in the developing world: in most of
India, locations in south east Asia, a swathe across sub-Saharan Africa, much of southern
and eastern Africa, and a few locations in Latin America (Fig 1). Semi-arid tropical regions
are characterized by unpredictable weather, long dry seasons, inconsistent rainfall, and soils
that are poor in nutrients. Sorghum, millet, cowpea, chickpea, pigeonpea and groundnut are
the vital crops that feed the poor people living in the SAT.
Environmental stresses represent the most limiting factors for agricultural productivity.
Apart from biotic stresses caused by plant pathogens, there are a number of abiotic stresses
such as extremes temperatures, drought, salinity and radiation which all have detrimental
effects on plant growth and yield, especially when several occur together (Mittler 2006)
A real story of bioethanol from biomass : Malaysia perspective
No full textRising fossil fuel prices associated with growing demand for energy, and environment concerns are the key factors driving strong interest in renewable energy sources, particular in biofuel. Biofuel refers to any type of fuel whose energy is derived from plant materials. Biofuel which includes solid biomass, liquid fuels and various biogases is among the most rapidly growing renewable energy technologies in recently. Biofuels are commonly divided into two groups based on the technology maturity which using the terms “conventional” and “advanced” for classification. Conventional biofuel technologies include well-established processes that are already producing biofuels on a commercial scale. These biofuels, commonly referred to as first-generation, include sugar- and starch-based ethanol, oil-crop based biodiesel and straight vegetable oil, as well as biogas derived through anaerobic digestion. First generation biofuel processes are useful but limited in most cases: there is a threshold above which they cannot produce enough biofuel without threatening food supplies and biodiversity. Whereas, advanced biofuel technologies are extensions from conventional technologies which some are still in the research and development (R&D), pilot or demonstration phase and they are commonly referred to as second- or third-generation. This category includes hydrotreated vegetable oil (HVO), which is based on animal fat and plant oil, as well as bioethanol based on lignocellulosic biomass, such as cellulosic-ethanol. Although there are wide varieties of advanced biofuels conversion technologies exists today, but they are not commercially available yet. Nevertheless, the most commercializable technology and most used biofuel on the global market is bioethanol
Development and early stage investigation of carbohydrate-based delivery agents for boron neutron capture therapy
No full textCancer represents one of the biggest health challenges in the world, and even with immense research and effort being put into developing and optimizing novel cancer treatments, the ultimate cure has not been found. Surgery and/or chemotherapy will provide treatment up to a certain extent and finding novel approaches which are selective and effective is detrimental for extending the life expectancy of patients with recurring cancer. One of promising cancer therapies is boron neutron capture therapy (BNCT). In order to enable the full potential of BNCT, novel delivery agents of 10B atoms, one of the two major components of the therapy, are needed.
Carbohydrates allow for the world around us and the life inside us to look and function the way it does on a daily basis. Cancer cells cannot live and grow without carbohydrates and due to their inefficient D-glucose metabolism, they have higher D-glucose uptake compared to healthy tissue. This characteristic behaviour of cancer cells is the foundation of the magic bullet approach for novel delivery agents for BNCT presented in this thesis.
The work of this PhD project consists of the design, synthesis, and structural characterisation of a library of glycoconjugates. The synthesis performed combines the fundamental principles of carbohydrate chemistry, and the use of protective group chemistry for manipulation of the hydroxyl groups presented in a monosaccharide unit. An important aspect of the PhD project was the detailed structural characterisation of synthesised compounds by the use of NMR spectroscopy and spectral simulation programs, which allowed for detailed analytical reports.
The work obtained throughout this medicinal chemistry project resulted in the creation of a library of glycoconjugates for the purpose of creating novel carbohydrate-based delivery agents for BNCT. The goal was to find delivery agents that would be able to outperform the agents currently used in clinics and find the prime glycoconjugate which could further go towards in vivo assessment and neutron studies.Cancer representerar en av de största hälsoutmaningarna i världen. Trots de enorma insatserna på forskning och utveckling av nya och förbättrade cancerbehandlingar har det ultimata botemedlet inte hittats. Kirurgi och/eller kemoterapi tillåter behandling av cancer till en viss utsträckning men selektivare och effektivare behandlingsstrategier behövs för att bota svåra cancer fall samt förlänga livslängden för patienter med återkommande cancer. En lovande cancerterapi som har stor potential är borneutroninfångningsterapi (BNCT). För att möjliggöra effektivare och mera framgångsrika BNCT-behandlingar behövs dock nya 10B-leverantörmolekyler.
Kolhydrater har en avgörande roll i hur världen omkring oss ser ut och hur de biologiska processerna inom oss fungerar på en daglig basis. Cancerceller kan inte leva och växa utan kolhydrater och på grund av sin ineffektiva D-glukosmetabolism uppvisar de ett högre upptag av D-glukos jämfört med frisk vävnad. Detta karakteristiska beteende hos cancerceller ligger som grund för leverantörstrategierna för BNCT som presenteras i denna avhandling.
Mitt doktorandprojekt fokuserade på design, syntes och strukturell karakterisering av ett bibliotek av glykokonjugat som möjliga leverantörmolekyler för BNCT. Genom att kombinera kolhydraters grundläggande egenskaperna med robusta skyddsgruppsstrategier kunde reaktiviteten hos monosackaridenheters funktionella grupper bemästras. Under doktorandprojektets gång placerades särskild vikt på detaljerad strukturell karakterisering av de syntetiserade föreningarna med hjälp av kärnmagnetisk resonansspektroskopi för att verifiera molekylernas struktur och produkternas renhet.
Under doktorandprojektet framställdes ett bibliotek av kolhydratbaserade 10B-leverantörmolekyler för BNCT. De fundamentala biokemiska grunderna för den utvalda leverantörstrategin undersöktes i samband med projektet och vidare jämfördes potentialen av kolhydratbaserade leverantörmolekyler med strategier som för tillfället är i kliniskt bruk. Ett antal lovande föreningar kunde konstateras och i framtiden bör dessa undersökas noggrannare i mera ingående in vivo studier.ei saavutettav
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