Precise Assembly and Supramolecular Catalysis of Tetragonal- and Trigonal-Elongated Octahedral Coordination Containers

In the mononuclear title complex, [Co(N3)2(C12H8N4S)2], the cobalt(II) atom is located on an inversion centre and displays an axially weakly compressed octahedral coordination geometry. The equatorial positions are occupied by the N atoms of two 2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole ligands, whereas the axial positions are occupied by N atoms of the azide anions. The thiadiazole and pyridine rings linked to the metal are almost coplanar, with a maximum deviation from the mean plane of 0.0273 (16) Å. The cohesion of the crystal is ensured by weak C—H...N hydrogen bonds and by π–π interactions between pyridine rings [intercentroid distance = 3.6356 (11) Å], forming a layered arrangement parallel to (001). The structure of the title compound is isotypic with that of the analogous nickel(II) complex [Laachiret al.(2013).Acta Cryst.E69, m351–m352].

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Synthesis of a Macrobicyclic Thiazolium-Host and Supramolecular Catalysis of the Benzoin Condensation

Angewandte Chemie International Edition in English ◽

10.1002/anie.198611251 ◽

1986 ◽

Vol 25 (12) ◽

pp. 1125-1127 ◽

Cited By ~ 23

Author(s):

Heinz-Dieter Lutter ◽

Fran�ois Diederich

Keyword(s):

Supramolecular Catalysis ◽

Benzoin Condensation

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Asymmetric Synthesis of Octahedral Coordination Complexes (Eur. J. Inorg. Chem. 19/2011)

European Journal of Inorganic Chemistry ◽

10.1002/ejic.201190054 ◽

2011 ◽

Vol 2011 (19) ◽

pp. n/a-n/a

Author(s):

Eric Meggers

Keyword(s):

Asymmetric Synthesis ◽

Coordination Complexes ◽

Octahedral Coordination

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ChemInform Abstract: Synthesis, Characterization, and EPR Studies of Heteropoly Compounds with Iron(III) in Tetrahedral and Octahedral Coordination.

ChemInform ◽

10.1002/chin.198937014 ◽

1989 ◽

Vol 20 (37) ◽

Author(s):

H. WEINER ◽

H.-J. LUNK ◽

R. STOESSER ◽

R. LUECK

Keyword(s):

Octahedral Coordination ◽

Heteropoly Compounds

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Catalytic activity of Co-åkermanite and Co-pyroxene in oxidation reactions

Canadian Journal of Chemistry ◽

10.1139/v11-061 ◽

2011 ◽

Vol 89 (8) ◽

pp. 939-947 ◽

Cited By ~ 5

Author(s):

Irena Mihailova ◽

Dimitar Mehandjiev

Keyword(s):

Catalytic Activity ◽

Solid Phase ◽

Sol Gel ◽

Cobalt Content ◽

Octahedral Coordination ◽

Tetrahedral Coordination ◽

Oxidation Reactions ◽

Oxidation Of Co ◽

Phase Synthesis ◽

Catalytically Active

Two calcium–cobalt silicates were synthesized in which cobalt occupies different structural positions. The crystal phases belong to two main structural silicate types. In the Co-åkermanite structure (Ca2CoSi2O7), cobalt cations take tetrahedral coordination toward oxygen atoms. In the Co-pyroxene structure of CaCoSi2O6, cobalt displays octahedral coordination. Ca2CoSi2O7 was prepared by solid-phase synthesis and CaCoSi2O6 was prepared by sol–gel method. The synthesis of the phases was confirmed by XRD, FTIR, and EPR data. On the basis of the XPS analysis, it can be concluded that Co2+ cations exist in the studied silicates. Thus, it is possible to study the catalytic activity of two silicate phases containing Co2+ cations in different coordinations: tetrahedral and octahedral. It was found that cobalt silicates with crystal structures corresponding to pyroxene and åkermanite possess catalytic activity in the reactions of complete oxidation of CO and toluene. Co-pyroxene exhibits higher catalytic activity than Co-åkermanite, but the higher cobalt content on the surface of Co-pyroxene should also be taken into account. Then, it turns out that catalytically active complexes with Со2+ ions in tetrahedral coordination are more efficient than those with such ions in octahedral coordination when equal concentrations of cobalt were used on the surface of the catalysts.

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