Crystal structure,thermal analysis,and IR spectroscopic investigation of bis(2-amino-6-methyl) pyridinium sulfate

Synthesis, crystal structure refinement, phase transitions studied by thermal analysis, and IR spectroscopic investigation of 2C₆H₉N₂ < eqid2 > ⋅SO₄²⁻ are reported. The title compound crystallizes in the monoclinic space group C2/c (no. 15) with a = 10.5068(4) Å, b = 10.2225(5) Å, c = 14.0422(7) Å, and β = 104.489(3)^∘. A crystal packing diagram shows layers built by all the components of the structure and centered by planes z = 1/4 and 3/4. The pyridine substituents stack forming channels parallel to the c direction with dimensions of 4.163(1) Å and 5.148(4) Å. Thermal analysis shows that the anhydrous compound possesses an irreversible weak phase transition.     

Crystal structure and thermal analysis of 1,5-diammonium-2-methyl pentane sulfate monohydrate

Chemical preparation, x-ray single crystal, and thermal analysis of C₆H₁₈N₂SO₄·H₂O (denoted DMPS) are described. The compound crystallizes in the triclinic system with P space group. Its unit cell dimensions are a = 5.826(1) Å, b = 10.014(1) Å, c = 11.221(1) Å, = 66.716(1)°, = 84.395(1)°, = 83.759(1)°, V = 596.7(1) ų, and Z = 2. The DMPS structure is built up from inorganic chains parallel to the a axis and linked via O(W)-H···O hydrogen bonds. These chains are interconnected by organic groups. Thermal analysis reveals the presence of one water molecule in the structure and shows a reversible weak phase transition.     

Pharmacological Justification for the Medicinal Use of Plumeria rubra Linn. in Cardiovascular Disorders

Plumeria rubra (L.) is a traditional folkloric medicinal herb used to treat cardiovascular disorders. The present investigation was methodically planned to investigate the pharmacological foundations for the therapeutic effectiveness of P. rubra in cardiovascular illnesses and its underlying mechanisms. Ex vivo vaso-relaxant effects of crude leaf extract of P. rubra were observed in rabbit aorta ring preparations. Hypotensive effects were measured using pressure and force transducers connected to the Power Lab data acquisition system. Furthermore, P. rubra displayed cardioprotective properties in rabbits when they were exposed to adrenaline-induced myocardial infarction. In comparison to the intoxicated group, the myocardial infarction model showed decreased troponin levels, CK-MB, LDH, ALT, ALP, AST, and CRP, as well as necrosis, apoptosis, oedema, and inflammatory cell enrollment. P. rubra has revealed good antioxidant properties and prolonged the noradrenaline intoxicated platelet adhesion. Its anticoagulant, vasorelaxant, and cardioprotective effects in both in vivo and ex vivo investigations are enabled by blocking L-type calcium channels, lowering adrenaline, induced oxidative stress, and tissue tear, justifying its therapeutic utility in cardiovascular disorders.     

Conductance Study and Thermodynamics of Some Substituted Ammonium Salts with Crown Ethers in Aqueous Solution

A conductance study of the interaction between substituted ammonium ions with three crown ethers in aqueous solution has been carried out at different temperatures. The formation constants of the 1 : 1 complexes at various temperatures were determined from the molar conductance-mole ratio data and found to vary in the order 18C6 > 15C5 > 12C4 for the same salt and with the same crown, the formation constants vary in the order (C2H5)3NHCl > (C2H5)4NBr > (CH3)3NPhI.The enthalpy and entropy of complexation were determined from the temperature dependence of the formation constants. The results indicate that the complexation process is enthalpy unfavored and entropy favored. The influence on the thermodynamic data for different parameters such as cavity size of crown ethers and nature of salt are discussed.     

Conductance and Thermodynamic Study of the Interaction of Mixed Oxygen–N2–Donor Macrocycles with Ag(I), Ni(II) and Fe(III) in Acetonitrile Solutions

The thermodynamic stabilities of Ag⁺, Ni²⁺ and Fe³⁺with diaza-crown ethers have been determinedconductometrically in acetonitrile at temperatures of 293, 298, 303 and 308 K.Both the size of the macrocyclic ring and the hard and soft acidand base (HSAB) character of the metal ions influence the relative stabilities of the complexes. For the metal ions with diazacrown ethers the values of log K_f for the 1 : 1 complexesfollow the order Ag⁺ > Ni²⁺ > Fe³⁺in accordance with Pearson's principle of HSAB character. The enthalpy and entropy of complexation were determined from the temperature dependence of the complexationconstants. The complexation process is entropy governed.     

Effect of chain blockiness on the phase behavior of ethylene‐octene copolymer blends

New challenges and opportunities for polyolefin blends arise from the recent introduction of olefin block copolymers (OBCs). In this study, the effect of chain blockiness on the miscibility and phase behavior of ethylene‐octene (EO) copolymer blends was studied. Binary blends of two statistical copolymers (EO/EO blends) that differed in comonomer content were compared with blends of an EO with a blocky EO copolymer (EO/OBC blends). The blends were rapidly quenched to retain the phase morphology in the melt and the phase volumes were obtained by atomic force microscopy (AFM). Two EOs of molecular weight about 100 kg/mol were miscible if the difference in octene content was less than about 10 mol % and immiscible if the octene content difference was greater than about 13 mol %. The blocky nature of the OBCs reduced the miscibility and broadened the partial miscibility window of the EO/OBC blends compared with the EO/EO blends. The EO/OBC blends were miscible if the octene content difference was less than 7 mol % and immiscible above 13 mol % octene content difference. It was also found that the phase behavior of EO/OBC blends strongly depended on blend composition even for constituent polymers of about the same molecular weight. Significantly more demixing was observed in an OBC‐rich blend (EO/OBC 30/70 v/v) than in an OBC‐poor blend (EO/OBC 70/30 v/v). An interpretation based on extractable fractions of the OBC described the major features of the EO/OBC (30/70 v/v) blends. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1554–1572, 2009     

Juncenolides F and G, two new briarane diterpenoids from Taiwanese gorgonian Junceella juncea

Chemical investigation of the gorgonian coral Junceella juncea collected in Taiwan has resulted in the isolation of the two novel briarane-type diterpenoid compounds, juncenolides F (1) and G (2). The structures were determined on the basis of spectral studies, especially 1D and 2D NMR.     

An X-ray absorption study of two VOCl3-modified silicas: evidence for chloride-silica interactions

The structures of the sites formed in the gas-solid reactions of VOCl3 with the surfaces of a fumed silica (Aerosil) and a silica gel (Sylopol) were investigated by using X-ray absorption spectroscopy. XANES and EXAFS analysis at the vanadium K-edge reveal that the sites have a uniform first coordination sphere regardless of the origin or the extent of hydroxylation of the silica support (controlled by thermal treatment in vacuo at 100 and 500 degrees C). Analysis of the second coordination sphere was limited by the lack of structural uniformity. EXAFS curve-fitting confirmed that the sites are [triple bond]SiOVOCl2, but revealed an unexpected asymmetry in the V-Cl bond distances. The latter is suggested to be a manifestation of silicon-chloride interactions.     

Genetic analysis of posterior medial barrel subfield (PMBSF) size in somatosensory cortex (SI) in recombinant inbred strains of mice

Background  

Quantitative trait locus (QTL) mapping is an important tool for identifying potential candidate genes linked to complex traits. QTL mapping has been used to identify genes associated with cytoarchitecture, cell number, brain size, and brain volume. Previously, QTL mapping was utilized to examine variation of barrel field size in the somatosensory cortex in a limited number of recombinant inbred (RI) strains of mice. In order to further elucidate the underlying natural variation in mouse primary somatosensory cortex, we measured the size of the posterior medial barrel subfield (PMBSF), associated with the representation of the large mystacial vibrissae, in an expanded sample set that included 42 BXD RI strains, two parental strains (C57BL/6J and DBA/2J), and one F1 strain (B6D2F1). Cytochrome oxidase labeling was used to visualize barrels within the PMBSF.     

Deuterium nuclear magnetic resonance spectroscopy. II—distribution of deuterium in some labelled nitrogen heterocyclic compounds

Pyridine, methylpyridines, quinoline and isoquinoline have been labelled with deuterium using pre-reduced platinum dioxide (PtO₂·2H₂O) and heavy water. Their ²H chemical shifts from monodeuteriated TMS have been assigned. The extent of the labelling has been determined directly by ²H NMR spectroscopy.