1,721,133 research outputs found
Structural and Conformational Studies of 3-(6-Chloropyridazin-3-yl)-N,N-dimethylpiperazinium Iodide and 3-(6-Chloropyridazin-3-yl)-N,N-dimethylhomopiperazinium Iodide with Central Nicotinic Action
No full textThe structural characteristics of 3-(6-chloropyridazin-3-yl)-N,N-dimethylpiperazinium iodide (3c) and 3-(6-chloropyridazin-3-yl)-N,N-dimethylhomopiperazinium iodide (4c) have been investigated in order to understand their actions at the nAchR receptor. The results of the X-Ray molecular structures and of the conformational analysis have been compared with the structure of epibatidine that represents one of the most potent nicotinic agonist
Docking of 6-chloropyridazin-3-yl derivatives active on nicotinic acetylcholine receptors into molluscan Acetylcholine Binding Protein (AChBP)
No full textThe crystal structure of Acetylcholine Binding Protein (AChBP), homolog of the ligand binding domain of nAChR, has been used as model for computational investigations on the ligand-receptor interactions of derivatives of 6-chloropyridazine substituted at C3 with 3,8-diazabicyclo[3.2.1] octane, 2,5-diazabicyclo[2.2.1]heptane and with piperazine and homopiperazine, substituted or not at N4. The ligand-receptor complexes have been analyzed by docking techniques using the binding site of HEPES complexed with AChBP as template. The good relationship between the observed binding affinity and the calculated docking energy confirms that this model provides a good starting point for understanding the binding domain of neuronal nicotinic receptors. An analysis of the possible factors significant for the ligand recognition has evidenced, besides the cation-φ interaction, the distance between the chlorine atom of the pyridazinyl group and the carbonylic oxygen of Leu B112 as an important parameter in the modulation of the binding energy
Crystal and molecular structures of h3-propenyl and h3-2-methyl propenyl-bis(triphenylphosphine) platinum (II) perchlorates
No full textTetramethylammonium chlorodiphenylthiocyanatoantimonate(III)
No full textThe crystal structure of the title compound, (C4H12N)-[Sb(C6H5) Cl-2(NCS)], contains two cations and two anions in the asymmetric unit. The Sb atom exhibits a distorted pseudo-trigonal -bipyramidal coordination, with the phenyl groups and the lone pair of electrons in equatorial positions and N-bonded thiocyanate and Cl- ligands in axial positions
Synthesis and X-ray crystal structure of cationic polynuclear hydroxide acetylacetonate lanthanide(III) clusters with homodinuclear or heterodinuclear decacarbonyl hydrides: [HMo2(CO)10](-) and [HCrW(CO)(10)](-)
No full textThe synthesis and characterization of new polynuclear lanthanide(III) ionic clusters of general formula [Lng(acac)(16)(OH)(10)](+) [Mo-2(CO)(10)(mu-H)](-) (Ln=Sm,Eu, Gd, Dy, Yb) and [Sm-9(acac)(16)(OH)(10)](+) [CrW(CO)(10)(mu-H)](-) is reported. The polymuclear complexes, prepared under pure nitrogen atmosphere by interaction of the hydridic metal carbonyls with the beta-dichetonate Ln(acac)(3)(.)3H(2)O (Ln= Sm, Eu, Gd, Dy, Yb). The new clusters were characterized by elemental analysis, complexometric titration for Ln, atomic absorption for Cr, W and Mo, gas-volumetric analysis for CO, FTIR spectroscopy and single crystal X-ray structure determination of [Sm-9(acac)(16)(OH)(10)][Mo-2(CO)(10)(mu-H)]. The Eu and Yb complexes are isostructural to the Sm one for which, similarly to their homonuclear chromium and tungsten derivative analogues, a square antiprismatic arrangement of eight Sm ions with the ninth at the center of the antiprism has been foun
Key intermediates in the synthesis of enantiopure antagonists at NMDA receptors: a structural study
No full textThe two diastereomeric amino acid derivatives 8 (3aS,5R,6aS)-5-tert-butoxycarbonylamino-4,5,6,6a-tetrahydro-3aH-cyclopen ta[d]isoxazole-3,5-dicarboxylic acid diethyl ester, its epimer 9 (3aS,5S,6aS), and carboxylic acid 10 obtained by hydrolysis of 9, which are intermediates in the synthesis of novel NMDA receptor antagonists 6 and 7 (Fig. 1), have been characterized by X-ray studies at 293 K for 8 and 10, and at 100 K for 9. The configuration of the carbon binding the 5-tert-butoxycarbonylamino moiety (BOC) determines the different molecular complexity: the chain structure for 8, dimeric for 9, and chain dimers for 10. The pharmacophoric parameters in compound 8 (from which the active 7 is derived) are comparable with those observed for NMDA receptor antagonism, while 9 and 10 do not present the structural features, which match these pharmacophoric characteristics. (C) 2005 Elsevier Ltd. All rights reserved
Different binding modes of oxazoline ligand derived from nitrile and carbonyl complexes of Pt(II)
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The crystallized solvent could influence the lanthanide water bonding?
No full textTwo gadonilium DOTAM complexes [Gd(DOTAM)H2O](CF3SO3)(3) center dot 3H(2)O (1) and [Gd(DOTAM)H2O](CF3SO3)(3) center dot 0.5H(2)O center dot CH3CN (2) have the structure of the M isomer, with coordination geometry around the Gd ion capped square antiprismatic (SA). They differ for the Gd-O-water bond lengths of 2.396(6) and 2.474(7) angstrom in (2) where two independent molecules are present in the crystal cell. The factors influencing the Gd-O-water bond distance, important for the water exchange rate in MRI experiments, have been correlated to the different network of hydrogen bonds involving the Gd coordinated water molecule. The X-ray structure of the parent compound [Pr(DOTAM)H2O](CF3SO3)(3) center dot HO center dot CH3CN (3) reveals an unexpected twisted square antiprismatic (TSA) coordination geometry characteristic of the In isome
Cis-Dichloroplatinum(II) Complexes with dihydroimidazole and dihydrooxazole ligands: cis-Platin analogues ?
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