Search results for "HYDROGEN"
showing 10 items of 4254 documents
Orthorhombic polymorphs of twotrans-4-aminoazoxybenzenes
2002
The two isomeric compounds 4-amino-ONN-azoxybenzene [or 1-(4-aminophenyl)-2-phenyldiazene 2-oxide], i.e. the alpha isomer, and 4-amino-NNO-azoxybenzene [or 2-(4-aminophenyl)-1-phenyldiazene 2-oxide], i.e. the beta isomer, both C(12)H(11)N(3)O, crystallized from a polar solvent in orthorhombic space groups, and their crystal and molecular structures have been determined using X-ray diffraction. There are no significant differences in the bond lengths and valence angles in the two isomers, in comparison with their monoclinic polymorphs. However, the conformations of the molecules are different due to rotation along the Ar-N bonds. In the alpha isomer, the benzene rings are twisted by 31.5 (2)…
Twotrans-4-aminoazoxybenzenes
2001
Two isomeric trans-4-aminoazoxybenzenes, trans-1-(4-aminophenyl)-2-phenyldiazene 2-oxide (alpha, C(12)H(11)N(3)O) and trans-2-(4-aminophenyl)-1-phenyldiazene 2-oxide (beta, C(12)H(11)N(3)O), have been characterized by X-ray diffraction. The alpha isomer is almost planar, having torsion angles along the C(aryl)-N bonds of only 4.9 (2) and 8.0 (2) degrees. The relatively short C(aryl)-N bond to the non-oxidized site of the azoxy group [1.401 (2) A], together with the significant quinoid deformation of the respective phenyl ring, is evidence of conjugation between the aromatic sextet and the pi-electron system of the azoxy group. The geometry of the beta isomer is different. The non-substitute…
Bile acid–cysteamine conjugates: Structural properties, gelation, and toxicity evaluation
2011
Abstract Design, synthesis, and characterization of six novel bile acid–cysteamine conjugates together with investigation of their structural studies, gelation properties, and preliminary toxicity evaluation, are reported. Solid state properties of selected compounds were studied by means of X-ray diffraction and 13C CPMAS NMR spectroscopy. N-(2-thioethyl)-3α,7α,12α-trihydroxy-5β-cholan-24-amide was shown to exhibit (pseudo)polymorphism, and a single crystal structure of its non-stoichiometric hydrate is reported herein. Cholyl and dehydrocholyl derivatives bearing three functionalities in their steroidal backbone were shown to undergo self-assembly leading to gelation in certain organic so…
Identification of passive layers on Co in Alkaline solutions by photocurrent spectroscopy
2005
The photoelectrochemical behavior of passive films on Co has been studied as a function of the polarizing voltage and electrolyte composition. Passive layers formed at 0 V (standard hydrogen electrode, SHE) in 0.1 M NaOH consisted of Co(OH) 2 , whose bandgap value has been found to be 1.85 eV. Higher bandgap values (2.75 eV) have been measured for passive films formed in borate buffer at 0 V (SHE), which are mainly consist of CoO. The Eg values have been related to the film composition on the basis of a correlation between the bandgap of passive films and the electronegativity of their constituents.
Enhancing the multiplication of nucleopolyhedrovirus in vitro by manipulation of the pH
2009
Insect nucleopolyhedroviruses (NPVs) are studied widely as agents for biological control, as expression vectors for the production of heterologous proteins, and as transduction vectors for gene therapy applications. Most of these applications rely on the existence of cell lines that allow in vitro multiplication of the virus. The influence of pH in the medium culture on the multiplication of SeMNPV, HearSNPV and AcMNPV in different cell culture lines was investigated. The study showed a strong influence of the medium pH on the virus multiplication with the best results at pH 6.5, about half pH unit above the pH of insect culture media used most commonly. Additional experiments using a recom…
Dynamics of particulate major and trace elements in the lower reaches of the Daugava River and adjacent area of the Gulf of Riga (Baltic Sea).
2004
Suspended particulate matter (SPM) was collected in the freshwater-seawater mixing zone in the lower reaches of the Daugava River (Latvia) and adjacent marine area, during five cruises in 1998-2001. The study focused on biogeochemical phase exchange processes. SPM in the freshwater was found to be mainly allochthonous with a high content of organic matter, Mn and sorbed phosphate. Property-salinity plots suggested flocculation of humic-Fe complexes across the salinity gradient. The variability of sorbed phosphate was related to particulate Fe, although no dependence on pH and ionic strength was observed. The Mn contents of SPM mainly follow conservative mixing, but there are also indication…
A convenient route for the preparation of the monohydride catalyst trans-[RuCl(H)(dppe)2] (dppe=Ph2PCH2CH2PPh2): improved synthesis and crystal struc…
2013
Abstract A novel and improved room temperature synthesis of the monohydride catalyst trans-[RuCl(H)(dppe)2] complex (1, dppe (1,2-bis(diphenylphosphino)ethane) = Ph2PCH2CH2PPh2) proceeds through oxidation of methanol (the solvent) by the pentacoordinated cis-[RuCl(dppe)2][PF6] complex and t-BuOK as the base is described. Compound 1 was fully characterized by NMR (1H, 13C, 31P), ESI-MS(TOF +), FTIR and elemental analysis. The X-ray structure of 1 was reported for the first time and unambiguously confirms the trans-configuration of the complex.
Influence of the pH on the synthesis of reduced graphene oxide under hydrothermal conditions
2012
Here we describe the important role played by the pH on the morphology and structure of the reduced graphite oxide (rGO) samples obtained by hydrothermal treatment of the previously prepared GO. The nature of the resulting samples has been studied on the basis of a complete battery of experimental techniques.
Synthesis and characterisation of N-glycosyl amines from the reaction between 4,6-O-benzylidene-D-glucopyranose and substituted aromatic amines and a…
2001
Twelve N-glycosyl amines were synthesised using 4,6-O–benzylidene-D-glucopyranose and different substituted aromatic amines, including some diamines that resulted in bis-glycosyl amines. Another set of six N–glycosyl amines was synthesised using different hexoses and pentoses and 2–(o–aminophenyl)benzimidazole. All compounds were isolated as solid products and purified, their elemental compositions were established, and these were characterised by NMR (1H and 13C), UV–Vis, and FTIR spectroscopy, by FAB mass spectrometry (molecular-ion peaks gave molecular weights), and by their optical rotations. While the protected saccharide, 4,6-O-benzylidene-D-glucopyranose, exists as a mixture of β and…
Discovery of benzimidazole-based Leishmania mexicana cysteine protease CPB2.8ΔCTE inhibitors as potential therapeutics for leishmaniasis
2018
Abstract: Chemotherapy is currently the only effective approach to treat all forms of leishmaniasis. However, its effectiveness is severely limited due to high toxicity, long treatment length, drug resistance, or inadequate mode of administration. As a consequence, there is a need to identify new molecular scaffolds and targets as potential therapeutics for the treatment of this disease. We report a small series of 1,2‐substituted‐1H‐benzo[d]imidazole derivatives (9ad) showing affinity in the submicromolar range (Ki = 0.150.69 μM) toward Leishmania mexicanaCPB2.8ΔCTE, one of the more promising targets for antileishmanial drug design. The compounds confirmed activity in vitro against intrace…