Chemistry: Recent submissions
Now showing items 21-40 of 85
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Kinetic studies on the reactions of some tetrakis(arylisocyanide)cobalt(II) complexes with pyridine in 2,2,2-trifluoroethanol
(Springer, http://www.springer.com/chemistry/journal/11243, 2006)The interaction of pyridine with four tetraki(arylisocyanide)cobalt(II) complexes, [Co(CNR)4(ClO4)2] R = 2,6- Me2C6H3 (A), 2,4,6-Me3C6H2 (B), 2,6-Et2C6H3 (C) and 2,6-iPr2C6H3 (D), have been studied in 2,2,2-trifluoroeth ... -
Bis(pyrazolyl) palladium(II), platinum(II) and gold(III) complexes: Syntheses, molecular structures and substitution reactions with L-cysteine
(Elsevier Science Ltd, www.elsevier.com/locate/ica, 2009)A series of pyrazolyl palladium(II), platinum(II) and gold(III) complexes, [PdCl2(3,5-R2bpza)] {R = H (1), R = Me (2), bpza = bis-pyrazolyl acetic acid}, [PtCl2(3,5-R2bpza)] {R = H (3a), R = Me (4)}, [AuCl2(3,5- R2bpza)]Cl ... -
Tylosema esculentum extractives and their bioactivity
(Elsevier Science Ltd, http://www.elsevier.com/locate/bmc, 2011)The investigation of Tylosema esculentum (Morama) husks, cotyledons, and tuber yielded griffonilide 2, compound 1, griffonin 3, gallic acid 4, protocatechuic acid 5, b-sitosterol 6, behenic acid 7, oleic acid 8, sucrose ... -
A bichalcone from the twigs of Rhus pyroides
(Elsevier Science Ltd, http://www.elsevier.com/locate/phytochem, 2000)The twigs of Rhus pyroides yielded a novel bichalcone 2',40,21-trihydroxy-4',41-dimethoxy-4-O-51-bichalcone. It was identified on the basis of spectroscopic data including 1D and 2D NMR spectroscopy. The name rhuschalcone-1 ... -
An efficient synthesis of flavans from salicylaldehyde and acetophenone derivatives
(Elsevier Science Ltd, http://www.elsevier.com/locate/tetlet, 2011)An efficient total synthesis of flavans from the reactions of salicylaldehyde and acetophenone derivatives is reported. The synthesis involves preparation of chalcones through an aldol reaction followed by reduction of ... -
An unexpected 1,2-hydride shift in phosphoric acid-promoted cyclodimerization of styrene oxides under solvent-free conditions. A synthetic route towards 2,4-disubstituted 1,3-dioxolanes
(Elsevier Science Ltd, http://www.elsevier.com/locate/tetlet, 2009)A 1,2-hydride shift in the phosphoric acid-promoted cyclodimerization of styrene oxide and its chloro derivatives under solvent-free conditions leading to 2,4-disubstituted 1,3-dioxolanes is described. Methoxy substituents ... -
Identification of Cu and Ni indicator plants from mineralised locations in Botswana
(Elsevier www.elsevier.com/locate/jgeoexp, 2005)Plant species that accumulate high levels of metals in proportion to the metal content in the soil are of considerable interest in biogeochemical and biogeobotanical prospecting. This study was aimed at investigating ... -
Influence of weak and strong donor groups on the fluorescence parameters and the intersystem crossing rate constant
(Elsevier Science Ltd. www.elsevier.com/locate/saa, 2003)Please refer to the attached article for an ABSTRACT. The abstract was not uploaded here due to formula appearance problem in UBRISA. -
Fire and its influence on microbial community structure and soil biochemical properties in the Okavango Delta, Botswana
(Academic Journals. http://www.academicjournals.org/SRE, 2007)The influence of wild fires on microbial community structure, soil organic matter, sulphur oxidising and nitrifying microbial populations in the floodplains of the Okavango Delta of Botswana was assessed. Microbial ... -
Gaboroquinones A and B and 4'-O-demethylknipholone-4'-O-β-D-glucopyranoside, phenylanthraquinones from the roots of Bulbine frutescens
(American Chemical Society. http://pubs.acs.org/jnp/, 2002)The novel phenylanthraquinones 4'-O-demethylknipholone-4'-O-β-D-glucopyranoside (2) and gaboroquinones A (3) and B (4) were isolated from the African medicinal plant Bulbine frutescens. Biaryl 2 represents the first ... -
Progress in the chemistry of marketed traditionally used plants of Ethiopia
(Chemical Society of Ethiopia. http://www.aau.edu.et/faculties/sc/CSE/home.html, 1996) -
The phase separation behaviour and the viscoelastic properties of particles with non-adsorbing polymers: Part I - Experimental study
(Elseview Science B.V. www.elsevier.nl/locate/colsurfa, 2000)A series of well characterised cis-polyisoprene polymers have been added to dispersions of PHS coated PMMA particles in dodecane. At a molecular weight of 8000 g mol−1 and above, these systems showed phase separation at ... -
Viscosity, molecular weight and concentration relationships at 298K of low molecular weight cis-polyisoprene in a good solvent
(Elsevier B.V. www.elsevier.com/locate/colsurfa, 2007)Aseries of six well characterised homopolymers of cis-polyisoprene (PIP) ranging from 1180 to 115,000 molecular weight were utilised to explore viscosity and the scaling relationship between viscosity and concentration ... -
Stereoselective synthesis of 3,4,5,6-tetrahydroxycyclohexyl b-amino acid derivatives
(Elsevier Ltd. www.elsevier.com/ locate/tetlet, 2008)Stereoselective syntheses of racemic (1S,2R,3R,4R,5S,6R)- and (1S,2R,3R,4S,5S,6R)-3,4,5,6-tetrahydroxy derivatives of 2-aminocyclohexanecarboxylic acid have been achieved by a stereospecific Diels–Alder reaction between ... -
Viscosity behaviour of particles with non-adsorbing polymers Part III—experimental study
(Elsevier B.V. www.elsevier.com/locate/colsurfa, 2004)A series of well characterised cis-poly(isoprene) (PIP) polymers (Mw = 1180, 8000, 28 300, 31 500, 86 000, 115 000 and 130 000) have been added to dispersions of poly(12-hydroxystearic acid) (PHS) coated poly(methylmethacrylate) ... -
A fluorescence spectroscopic study of a coagulating protein extracted from Moringa oleifera seeds
(Elsevier B.V. www.elsevier.com/locate/colsurfb, 2007)The fluorescence studies of coagulating protein extracted from Moringa oleifera seeds have been studied using steady-state intrinsic fluorescence. The fluorescence spectra are dominated by tryptophan emission and the ... -
Volumetric Properties of (Difurylmethane + Alkan-1-ol) Binary Mixtures at 298.15 K
(Journal of Solution Chemistry., 2006)Densities (ρ) of the binary systems of {difurylmethane+(ethanol or propan-1- ol or butan-1-ol or pentan-1-ol or hexan-1-ol)} have been measured with an Anton Paar DMA 4500 vibrating-tube densimeter over the entire ... -
Prenylated arylbenzofuran derivatives from Morus mesozygia with antioxidant activity
(Elsevier Ltd. www.elsevier.com/locate/phytochem, 2008)Five prenylated arylbenzofurans, moracins Q–U, were isolated from Morus mesozygia (Moraceae). Their structures were elucidated on the basis of spectroscopic evidence. Along with these compounds, 3b-acetoxyurs- 12-en-11-one, ... -
Evaluation of methods for the isolation, detection and quantification of cyanobacterial hepatotoxins
(Elsevier Ltd. www.elsevier.com/locate/aquatox, 2006)Cyanobacterial hepatotoxins such as microcystins and nodularins have been responsible for the poisoning of both animals and humans who ingest or come into contact with toxic blooms. They are extremely stable in water due ... -
Recent results from natural product research at the University of Botswana
(IUPAC. http://www.iupac.org/publications/pac/, 2001)Marketed plants are very important items of trade in many parts of the world. The community uses these for a variety of purposes such as foods, cosmetics, flavors, spices, and medicines. It seems that plants that are ...