2,784 research outputs found

    Structural systematics of aryl-1,3-dithiane derivatives: crystal and energy-minimised structures, and Hirshfeld surface analysis

    Get PDF
    The crystal structure analysis of three aryl-1,3-dithiane derivatives, with aryl=4-methylphenyl (1), 4-chlorophenyl (2) and 2,4-dichlorophenyl (3), shows the three molecules to have very similar conformations, with the aryl ring lying on an approximate mirror plane that bisects the dithiane ring which adopts a chair conformation; the energy-minimised structures are consistent with the experimental structures. The greater barrier to rotation about the methine-C–C(ipso) bond in 3, cf. 1 and 2, is related to unfavourable intramolecular S···Cl interactions in the putative transition state. The molecular packing in 1–3, while globally similar, are distinct, being based on combinations of identifiable C–H···π(arene), C–H···S and C–Cl···π(arene) interactions. The lack of isostructural relationships points to the significance of the identified intermolecular interactions to direct molecular packing

    1-Butyl-1-chloro-3-methyl-3H-2,1λ4-benzoxatellurole: crystal structure and Hirshfeld analysis

    Get PDF
    Two independent molecules comprise the asymmetric unit in the title benzoxatellurole compound, C12H17ClOTe. The molecules, with the same chirality at the methine C atom, are connected into a loosely associated dimer by Te...O interactions, leading to a {...Te—O}2 core. The resultant C2ClO2 donor set approximates a square pyramid with the lone pair of electrons projected to occupy a position trans to the n-butyl substituent. Interestingly, the TeIV atoms exhibit opposite chirality. The major difference between the independent molecules relates to the conformation of the five-membered chelate rings, which is an envelope with the O atom being the flap, in one molecule and is twisted about the O—C(methine) bond in the other. No directional intermolecular interactions are noted in the molecular packing beyond the aforementioned Te...O secondary bonding. The analysis of the Hirshfeld surface reveals the dominance of H...H contacts, i.e. contributing about 70% to the overall surface, and clearly differentiates the immediate crystalline environments of the two independent molecules in terms of both H...H and H...Cl/Cl...H contacts

    Biological studies in childhood schizophrenia: Plasma and RBC cholinesterase activity

    Full text link
    Most investigations of possible metabolic aberrations in childhood schizophrenia failed to demonstrate differences between schizophrenic patients and control groups. Cholinesterase activity has not been previously reported in schizophrenic children. Similar studies with adult schizophrenics have not been consistent, despite some reports of abnormal cholinesterase activity. The present study reports the results of plasma (pseudo) cholinesterase and erythrocyte (true) cholinesterase activity in 16 male childhood schizophrenic patients and 16 male nonpsychotic hospitalized control patients. No significant differences were found between the two groups. An unexpected finding of high significance was the inverse correlation between acetylcholinesterase activity of erythrocytes and serotonin uptake by platelets in both the nonschizophrenic patients and the combined groups. This negative correlation was less significant in the schizophrenic patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44597/1/10803_2005_Article_BF01537744.pd

    4-Benzyl-1-(4-nitrophenyl)-1H-1,2,3-triazole: crystal structure and Hirshfeld analysis

    Get PDF
    The mol­ecule in the title compound, C15H12N4O2, has a twisted L-shape with the dihedral angle between the aromatic rings of the N-bound benzene and C-bound benzyl groups being 70.60 (9)°. The nitro group is co-planar with the benzene ring to which it is connected [C—C—N—O torsion angle = 0.4 (3)°]. The three-dimensional packing is stabilized by a combination of methyl­ene-C—H...O(nitro), methyl­ene-C—H...π(phen­yl), phenyl-C—H...π(triazol­yl) and nitro-O...π(nitro­benzene) inter­actions, along with weak π(triazol­yl)–π(nitrobenzene) contacts [inter-centroid distance = 3.8386 (10) Å]. The importance of the specified inter­molecular contacts has been verified by an analysis of the calculated Hirshfeld surface

    Structural, Hirshfeld surface and theoretical analysis of two conformational polymorphs of N,Nâ€Č-bis(pyridin-3-ylmethyl)oxalamide

    Get PDF
    The common feature of two conformational polymorphs of N,Nâ€Č-bis(pyridin-3-ylmethyl)oxalamide is their crystallisation in the monoclinic space group P21/c with Z=4. In low symmetry form 1, the central core is effectively planar and the terminal pyridyl rings adopt a syn-periplanar conformation. In the high symmetry form, 2, there are two independent molecules in the asymmetric unit but each is located about a centre of inversion. The rings again are almost perpendicular to the central plane but, from symmetry are anti-periplanar. Computational chemistry shows that symmetric molecules with syn (two-fold) and anti (centrosymmetric) conformations have nearly identical energies. In the molecular packing of each of 1 and 2, supramolecular tapes based on amide-N–H···O(amide) hydrogen bonding are found. In 1, these are connected into layers by C–H···N(pyridyl) interactions, while in 2, the chains are linked into a three-dimensional architecture by C–H···N(pyridyl) interactions. The importance of hydrogen bonding is emphasised in the analysis of the Hirshfeld surfaces

    Crystallographic, DFT and docking (cathepsin B) studies on an organotellurium(IV) compound

    Get PDF
    Some biologically active organotellurium compounds exhibit inhibitory potency against cathepsin B. In this study, an alkyl derivative, viz. [CH3(CH2)2C(I)=C(H)](nBu)TeI2, 1, has been structurally characterised by X-ray crystallography and shown to be coordinated within a C2I2 donor set. When the stereochemically active lone pair of electrons is taken into account, a distorted trigonal bipyramidal geometry results with the iodide atoms in axial positions. Both intra- and inter-molecular Te···I interactions are also noted. If all interactions are considered, the coordination geometry is based on a Κ-pentagonal bipyramidal geometry. An unusual feature of the structure is the curving of the functionalised C5 chain. This feature has been explored by DFT methods and shown to arise as a result of close C–H···I interactions. A docking study (cathepsin B) was performed to understand the inhibition mechanism and to compare the new results with previous observations. Notably, 1 has the same pose exhibited by analogous biologically active compounds with aryl groups. Thus, the present study suggests that (alkyl)2TeX2 compounds should also be evaluated for biological activity

    Flavobacterium plurextorum sp. nov. isolated from farmed rainbow trout (Oncorhyncus mykiss)

    Get PDF
    Five strains (1126-1H-08T, 51B-09, 986-08, 1084B-08 and 424-08) were isolated from diseased rainbow trout. Cells were Gram-negative rods, 0.7 mm wide and 3 mm long, non-endospore-forming, catalase and oxidase positive. Colonies were circular, yellow-pigmented, smooth and entire on TGE agar after 72 hours incubation at 25uC. They grew in a temperature range between 15uC to 30uC, but they did not grow at 37uCor 42uC. Based on 16S rRNA gene sequence analysis, the isolates belonged to the genus Flavobacterium. Strain 1126-1H-08T exhibited the highest levels of similarity with Flavobacterium oncorhynchi CECT 7678T and Flavobacterium pectinovorum DSM 6368T (98.5% and 97.9% sequence similarity, respectively). DNA–DNA hybridization values were 87 to 99% among the five isolates and ranged from 21 to 48% between strain 1126-1H- 08T, selected as a representative isolate, and the type strains of Flavobacterium oncorhynchi CECT 7678T and other phylogenetic related Flavobacterium species. The DNA G+C content of strain 1126-1H-08T was 33.2 mol%. The predominant respiratory quinone was MK-6 and the major fatty acids were iso-C15:0 and C15:0. These data were similar to those reported for Flavobacterium species. Several physiological and biochemical tests differentiated the novel bacterial strains from related Flavobacterium species. Phylogenetic, genetic and phenotypic data indicate that these strains represent a new species of the genus Flavobacterium, for which the name Flavobacterium plurextorum sp. nov. was proposed. The type strain is 1126- 1H-08T ( = CECT 7844T = CCUG 60112T)

    The Extragalactic Distance Scale Key Project XXVII. A Derivation of the Hubble Constant Using the Fundamental Plane and Dn-Sigma Relations in Leo I, Virgo, and Fornax

    Full text link
    Using published photometry and spectroscopy, we construct the fundamental plane and D_n-Sigma relations in Leo I, Virgo and Fornax. The published Cepheid P-L relations to spirals in these clusters fixes the relation between angular size and metric distance for both the fundamental plane and D_n-Sigma relations. Using the locally calibrated fundamental plane, we infer distances to a sample of clusters with a mean redshift of cz \approx 6000 \kms, and derive a value of H_0=78+- 5+- 9 km/s/Mpc (random, systematic) for the local expansion rate. This value includes a correction for depth effects in the Cepheid distances to the nearby clusters, which decreased the deduced value of the expansion rate by 5% +- 5%. If one further adopts the metallicity correction to the Cepheid PL relation, as derived by the Key Project, the value of the Hubble constant would decrease by a further 6%+- 4%. These two sources of systematic error, when combined with a +- 6% error due to the uncertainty in the distance to the Large Magellanic Cloud, a +- 4% error due to uncertainties in the WFPC2 calibration, and several small sources of uncertainty in the fundamental plane analysis, combine to yield a total systematic uncertainty of +- 11%. We find that the values obtained using either the CMB, or a flow-field model, for the reference frame of the distant clusters, agree to within 1%. The Dn-Sigma relation also produces similar results, as expected from the correlated nature of the two scaling relations. A complete discussion of the sources of random and systematic error in this determination of the Hubble constant is also given, in order to facilitate comparison with the other secondary indicators being used by the Key Project.Comment: 21 pages, 3 figures, Accepted for publication in Ap
    • 

    corecore