Bipyridine Molecules (bipyridine + molecule)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

Inclusion Behavior of ,-Cyclodextrin with Bipyridine Molecules: Factors Governing Host-Guest Inclusion Geometries

CHEMISTRY - AN ASIAN JOURNAL, Issue 3 2009
Yan-Li Zhao Dr.
Abstract Guest Effect: The differences of nitrogen atom positions and the bridge bonds linked to two pyridine rings of some bipyridine guests can significantly affect the binding abilities and inclusion geometries of ,-cyclodextrin with the guests in both the solution and solid states. The 1:1 complexation of ,-cyclodextrin (,-CD) with structurally similar bipyridine guests which lead to the formation of six inclusion complexes (1,6) of ,-CD with 4,4,-vinylenedipyridine, 2,2,-vinylenedipyridine, 1-(2-pyridyl)-2-(4-pyridyl)ethylene, 4,4,-ethylene-dipyridine, 4,4,-dithiodipyridine, and 2,2,-dithiodipyridine has been investigated comprehensively by X-ray crystallography in the solid state and by 1H,NMR spectroscopy and microcalorimetric titration in aqueous solution. The complex formation constants (KS) for the stoichiometric 1:1 host,guest inclusion complexation of ,-CD with the bipyridine derivatives were determined in aqueous solution by microcalorimetry and the host,guest inclusion geometries of the complexes were deduced from 1H ROESY NMR spectroscopy. It transpires that the guest bipyridine molecules are included in the ,-CD cavity with a range of different inclusion geometries. In the solid state, the crystal superstructures for the ,-CD complexes 1, 4, and 5 are characterized by the triclinic crystal system (space group P1) commensurate with AAAA type supramolecular aggregation. By contrast, the ,-CD complexes 2, 3, and 6 display either monoclinic (space group P21) or orthorhombic (space group C2221) crystal systems, characteristic of ABAB type supramolecular aggregation. The results demonstrate that the relative locations of the nitrogen atom positions and the bridge-bond links between the two pyridine rings in these bipyridine guests, not only lead to distinct crystal systems and space groups, but also to different binding geometries and thermodynamical parameters on complexation of the bipyridines with ,-CD. The knowledge obtained from this research improves our understanding of the molecular recognition and self-assembly processes exhibited by ,-CD, both in the solid state and in aqueous solution. [source]

Synthesis, Crystal Structure, and Magnetic Properties of Two Manganese(II) Polymers Bearing Ferrocenecarboxylato Ligands

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2007
Zilu Chen
Abstract Reactions of Mn(ClO4)2·6H2O with FcCO2Na [Fc = (,5 -C5H4)Fe(,5 -C5H5)] in methanol solution gave [Mn3(FcCO2)6(CH3OH)4]n (1), and, in the presence of 4,4,-bipyridine (4,4,-bpy), [Mn3(FcCO2)6(H2O)2(4,4,-bpy)]n (2). Both complexes have the similar chains with a sequence of ,Mn,(,2 -COO)n,Mn,(,2 -COO),Mn,(,2 -COO),Mn,(,2 -COO)n,Mn, (n = 4 and 2 for complex 1 and 2, respectively), which are constructed alternatively from mononuclear [MnII] units and dinuclear [Mn2(FcCO2)4] units by ,2 -ferrocenecarboxylato- O,O, bridging. The two MnII ions in the dinuclear [Mn2(FcCO2)4] units of complex 1 are connected by four ferrocenecarboxylato ligands to form a swastika-like shaped skeleton, which is rare in metallocenecarboxylato complexes. However, the two MnII ions in the dinuclear [Mn2(FcCO2)4] units of complex 2 are bridged only by two carboxylato ligands, and the other two ferrocenecarboxylato ligands in this unit bind in a chelating mode. The chains in complex 2 are further interconnected by the coordinated 4,4,-bipyridine molecules to form two-dimensional coordination sheets. Magnetic susceptibility measurements revealed a weak antiferromagnetic coupling for both complexes. A model Heisenberg chain comprising classical spins coupled through alternating exchange interactions J1,J1,J2 (AF1,AF1,AF2) is proposed to describe the magnetic behavior. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

A three-dimensional homochiral metal,organic framework constructed from manganese(II) with S -carboxymethyl- N -(p -tosyl)- l -cysteine and 4,4,-bipyridine

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2009
Wei Xiong
In the chiral polymeric title compound, poly[aqua(4,4,-bipyridine)[,3 - S -carboxylatomethyl- N -(p -tosyl)- l -cysteinato]manganese(II)], [Mn(C12H13NO6S2)(C10H8N2)(H2O)]n, the MnII ion is coordinated in a distorted octahedral geometry by one water molecule, three carboxylate O atoms from three S -carboxyatomethyl- N -(p -tosyl)- l -cysteinate (Ts-cmc) ligands and two N atoms from two 4,4,-bipyridine molecules. Each Ts-cmc ligand behaves as a chiral ,3 -linker connecting three MnII ions. The two-dimensional frameworks thus formed are further connected by 4,4,-bipyridine ligands into a three-dimensional homochiral metal,organic framework. This is a rare case of a homochiral metal,organic framework with a flexible chiral ligand as linker, and this result demonstrates the important role of noncovalent interactions in stabilizing such assemblies. [source]

Inclusion Behavior of ,-Cyclodextrin with Bipyridine Molecules: Factors Governing Host-Guest Inclusion Geometries

CHEMISTRY - AN ASIAN JOURNAL, Issue 3 2009
Yan-Li Zhao Dr.
Abstract Guest Effect: The differences of nitrogen atom positions and the bridge bonds linked to two pyridine rings of some bipyridine guests can significantly affect the binding abilities and inclusion geometries of ,-cyclodextrin with the guests in both the solution and solid states. The 1:1 complexation of ,-cyclodextrin (,-CD) with structurally similar bipyridine guests which lead to the formation of six inclusion complexes (1,6) of ,-CD with 4,4,-vinylenedipyridine, 2,2,-vinylenedipyridine, 1-(2-pyridyl)-2-(4-pyridyl)ethylene, 4,4,-ethylene-dipyridine, 4,4,-dithiodipyridine, and 2,2,-dithiodipyridine has been investigated comprehensively by X-ray crystallography in the solid state and by 1H,NMR spectroscopy and microcalorimetric titration in aqueous solution. The complex formation constants (KS) for the stoichiometric 1:1 host,guest inclusion complexation of ,-CD with the bipyridine derivatives were determined in aqueous solution by microcalorimetry and the host,guest inclusion geometries of the complexes were deduced from 1H ROESY NMR spectroscopy. It transpires that the guest bipyridine molecules are included in the ,-CD cavity with a range of different inclusion geometries. In the solid state, the crystal superstructures for the ,-CD complexes 1, 4, and 5 are characterized by the triclinic crystal system (space group P1) commensurate with AAAA type supramolecular aggregation. By contrast, the ,-CD complexes 2, 3, and 6 display either monoclinic (space group P21) or orthorhombic (space group C2221) crystal systems, characteristic of ABAB type supramolecular aggregation. The results demonstrate that the relative locations of the nitrogen atom positions and the bridge-bond links between the two pyridine rings in these bipyridine guests, not only lead to distinct crystal systems and space groups, but also to different binding geometries and thermodynamical parameters on complexation of the bipyridines with ,-CD. The knowledge obtained from this research improves our understanding of the molecular recognition and self-assembly processes exhibited by ,-CD, both in the solid state and in aqueous solution. [source]