Stereochemical studies on cyclic peptides—VIII. Conformational analysis of hydrogen bonded cyclohexaglycyl molecule with a centre of inversion symmetry

1977 ◽  
Vol 86 (5) ◽  
pp. 443-454 ◽  
Author(s):  
G Manjula ◽  
C Ramakrishnan ◽  
K P Sarathy
Keyword(s):  
Conformational Analysis ◽  
Cyclic Peptides ◽  
Inversion Symmetry ◽  
Hydrogen Bonded

Conformational Analysis of SomeC2-Symmetric Cyclic Peptides Containing Tetrahydrofuran Amino Acids†

2006 ◽  
Vol 71 (16) ◽  
pp. 6240-6243 ◽  
Author(s):  
Tushar Kanti Chakraborty ◽  
Saumya Roy ◽  
Dipankar Koley ◽  
Samit Kumar Dutta ◽  
Ajit Chand Kunwar
Keyword(s):  
Amino Acids ◽  
Conformational Analysis ◽  
Cyclic Peptides

scholarly journals Isotypic MnIIand FeIIbinuclear complexes of the ligand 5,6-bis(pyridin-2-yl)-pyrazine-2,3-dicarboxylic acid

2016 ◽  
Vol 72 (10) ◽  
pp. 1412-1416
Author(s):  
Monserrat Alfonso ◽  
Helen Stoeckli-Evans
Keyword(s):  
Hydrogen Bonds ◽  
Dicarboxylic Acid ◽  
Metal Ion ◽  
Three Dimensional ◽  
Water Molecules ◽  
Inversion Symmetry ◽  
Π Interactions ◽  
Metal Atoms ◽  
Hydrogen Bonded

The title isotypic complexes, bis[μ-5,6-bis(pyridin-2-yl)pyrazine-2,3-dicarboxylato]-κ4N1,O2,N6:O3;κ4O3:N1,O2,N6-bis[diaquamanganese(II)] tetrahydrate, [Mn2(C16H8N4O4)2(H2O)4]·4H2O, (I), and bis[μ-5,6-bis(pyridin-2-yl)pyrazine-2,3-dicarboxylato]-κ4N1,O2,N6:O3;κ4O3:N1,O2,N6-bis[diaquairon(II)] tetrahydrate, [Fe2(C16H8N4O4)2(H2O)4]·4H2O, (II), are, respectively, the manganese(II) and iron(II) complexes of the ligand 5,6-bis(pyridin-2-yl)-pyrazine-2,3-dicarboxylic acid. The complete molecule of each complex is generated by inversion symmetry. Each metal ion is coordinated by a pyrazine N atom, a pyridine N atom, two carboxylate O atoms, one of which is bridging, and two water O atoms. The metal atoms haveMN2O4coordination geometries and the complexes have a cage-like structure. In the crystals of both compounds, the complexes are linked by O—H...O and O—H...N hydrogen bonds involving the coordinating water molecules, forming chains along [100]. These chains are linked by O—H...O hydrogen bonds involving the non-coordinating water molecules, forming layers parallel to (011). The layers are linked by pairs of C—H...O hydrogen bonds and offset π–π interactions, so forming a hydrogen-bonded three-dimensional framework.

Cyclic peptides from the ascidian Lissoclinum patella: conformational analysis of patellamide D by x-ray analysis and molecular modeling

1989 ◽  
Vol 54 (14) ◽  
pp. 3463-3472 ◽  
Author(s):  
Francis J. Schmitz ◽  
Mohamad B. Ksebati ◽  
James S. Chang ◽  
J. L. Wang ◽  
M. Bilayet Hossain ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Conformational Analysis ◽  
Cyclic Peptides ◽  
X Ray ◽  
Lissoclinum Patella

Pseudosymmetry in a cyclopalladated compound

2012 ◽  
Vol 68 (8) ◽  
pp. m223-m225 ◽  
Author(s):  
William Raven ◽  
Irmgard Kalf ◽  
Ulli Englert
Keyword(s):  
Title Complex ◽  
Unit Cell ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
Enantiomerically Pure ◽  
Space Group ◽  
Hydrogen Bonded

The enantiomerically pure title complex, [SP-4-4]-(R)-[2-(1-aminoethyl)phenyl-κ2C1,N]chlorido(quinoline-κN)palladium(II) acetone hemisolvate, [Pd(C8H10N)Cl(C9H7N)]·0.5C3H6O, crystallizes with four molecules of the organopalladium complex and two molecules of acetone in the asymmetric unit. This corresponds to a discrete hydrogen-bonded aggregate and to the content of the unit cell in the space groupP1. Pronounced pseudo-inversion symmetry relates pairs of these objects in the asymmetric unit.

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