Synthesis and molecular structure of [Ni4(S2)(SCH2CH2S)4]2-, a mixed nickel-disulfide-thiolate anion with a prismatic Ni4S2 core

1988 ◽  
Vol 27 (22) ◽  
pp. 3896-3899 ◽  
Author(s):  
Wolfgang Tremel ◽  
Gerald Henkel
Keyword(s):  
Molecular Structure ◽  
Thiolate Anion

A three-dimensional metal–organic polymer: poly[bis(μ2-pyrimidine-2-thiolato-κ4N1,S:S,N3)lead(II)]

2015 ◽  
Vol 71 (7) ◽  
pp. 517-520 ◽  
Author(s):  
Vania Denise Schwade ◽  
Ernesto Schulz Lang ◽  
Luana Floriano
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Metal Ion ◽  
Three Dimensional ◽  
Organic Polymer ◽  
Covalent Bonds ◽  
Coordination Environment ◽  
Dimensional Network ◽  
Thiolate Anion ◽  
Metal Organic

The title compound, [Pb(C4H3N2S)2]n, was prepared by the reaction of [Pb(OAc)2]·3H2O (OAc is acetate) with pyrimidine-2-thione in the presence of triethylamine in methanol. In the crystal structure, the PbIIatom has an N4S4coordination environment with four ligands coordinated by N- and S-donor atoms. This compound shows that the pyrimidine-2-thiolate anion can lead to a three-dimensional network when the coordination number of the metal ion can be higher than 6, as is the case with the PbIIion. This compound presents only covalent bonds, showing that despite the possibility of the hemidirected geometries of PbII, the eight-coordinated ion does not allow the formation of an isolated molecular structure with pyrimidine-2-thiolate as the ligand.

Molecular Structure of the Outermost Cell Wall Component of Spirillum Serpens

1977 ◽  
Vol 35 ◽  
pp. 342-343
Author(s):  
Wah Chiu ◽  
David Grano
Keyword(s):  
Molecular Structure ◽  
Cell Wall ◽  
Outer Membrane ◽  
Gel Electrophoresis ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Cell Wall Component ◽  
Protein Components ◽  
Exposure Technique ◽  
Structural Aspects

The periodic structure external to the outer membrane of Spirillum serpens VHA has been isolated by similar procedures to those used by Buckmire and Murray (1). From SDS gel electrophoresis, we have found that the isolated fragments contain several protein components, and that the crystalline structure is composed of a glycoprotein component with a molecular weight of ∽ 140,000 daltons (2). Under an electron microscopic examination, we have visualized the hexagonally-packed glycoprotein subunits, as well as the bilayer profile of the outer membrane. In this paper, we will discuss some structural aspects of the crystalline glycoproteins, based on computer-reconstructed images of the external cell wall fragments.The specimens were prepared for electron microscopy in two ways: negatively stained with 1% PTA, and maintained in a frozen-hydrated state (3). The micrographs were taken with a JEM-100B electron microscope with a field emission gun. The minimum exposure technique was essential for imaging the frozen- hydrated specimens.

On the relation between isotope effects on vapour pressure and molecular structure

1963 ◽  
Vol 60 ◽  
pp. 52-55
Author(s):  
István Kiss ◽  
Lajos Matus ◽  
István Opauszky
Keyword(s):  
Molecular Structure ◽  
Vapour Pressure ◽  
Isotope Effects

Structure elucidation by NMR spectroscopy: Assisted analysis from spectra to molecular structure

Planta Medica ◽  
2014 ◽  
Vol 80 (10) ◽  
Author(s):  
S Groscurth ◽  
T Kühn ◽  
P Kessler ◽  
V Rukachaisirikul
Keyword(s):  
Molecular Structure ◽  
Nmr Spectroscopy ◽  
Structure Elucidation ◽  
Assisted Analysis

Activity of Plasmin and Streptokinase-Activator on Substituted Arginine and Lysine Esters

1966 ◽  
Vol 16 (01/02) ◽  
pp. 018-031 ◽  
Author(s):  
S Sherry ◽  
Norma Alkjaersig ◽  
A. P Fletcher
Keyword(s):  
Molecular Structure ◽  
Methyl Ester ◽  
Comparative Studies ◽  
Esterase Activity ◽  
Methyl Esters ◽  
Hydrolytic Activity ◽  
The Other ◽  
Other Hand

SummaryComparative studies have been made of the esterase activity of plasmin and the streptokinase-activator of plasminogen on a variety of substituted arginine and lysine esters. Human plasmin preparations derived by different methods of activation (spontaneous in glycerol, trypsin, streptokinase (SK) and urokinase) are similar in their esterase activity; this suggests that the molecular structure required for such esterase activity is similar for all of these human plasmins. Bovine plasmin, on the other hand, differs from human plasmin in its activity on several of the substrates studied (e.g., the methyl esters of benzoyl arginine and tosyl, acetyl and carbobenzoxy lysine), a finding which supports the view that molecular differences exist between the two animal plasmins. The streptokinase-activator hydrolyzes both arginine and lysine esters but the ratios of hydrolytic activity are distinct from those of plasmin and of other activators of plasminogen. The use of benzoyl arginine methyl ester as a substrate for the measurement of the esterase activity of the streptokinase-activator is described.

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