Ligand-assisted templating

Fig. 4 Ligand assisted templating mechanism for the synthesis of niobium oxide. The amine surfactant forms covalent bonds with the niobium (V) ethoxide, resulting in the formation of a hybrid interface. Upon exposure to water, the system organizes into various structures such as bidimensional hexagonal (Nb-TMSl), three-dimensional hexagonal (Nb-TMS2), lamellar (Nb-TMS4), or a cubic phase. (Nb-TMS3 is not shown in the figure.) (From Ref...

New Supramolecular Approaches in Transition Metal Catalysis Template-Ligand Assisted Catalyst Encapsulation, Self-Assembled Ligands and Supramolecular Catalyst Immobilization... 

Antonelli, D.M. Nakahira, A. Ying, J.Y. Ligand-assisted liquid crystal templating in mesoporous niobium oxide molecular sieves. Inorg. Chem. 1996, 55 (11), 3126-3136. 

Keywords Scanning tunneling microscopy assisted template Axial ligand Redox... 

Detailed studies 2,93 of Cu(II)-assisted template condensations and some subsequent reactions (e.g. reduction by sodium borohydride) leading to novel macrocyclic ligands have been reported. It has been shown that treatment of complexes containing ligands bearing pendant -OR (R = H, Me) substituents with Na[BH4] in a mettianol/water mixture leads to reduction of the coordinated ligand. Scheme 10.23 ... 

Kuil, M., Goudriaan, P.E., Kleij, A.W, Tooke, D.M., Spek, A.L., van Leeuwen, P.W.N.M. and Reek, J.N.H. (2007) Rigid bis-zinc(ll) salphenbuilding blocks forthe formation of template-assisted bidentate ligands and their application in catalysis. Dalton Trans, 2311-2320. 

Virtually all types of metal ions have been complexed with macrocyclic ligands.2-7 Complexes of transition metal ions have been studied extensively with tetraaza macrocycles (Chapter 21.2). Porphyrin and porphyrin-related complexes are of course notoriously present in biological systems and have been receiving considerable investigative attention (Chapter 22).8 Macrocyclic ligands derived from the Schiffbase and template-assisted condensation reactions of Curtis and Busch also figure prominantly with transition metal ions.6,7 The chemistry of these ions has been more recently expanded into the realm of polyaza, polynucleating and polycyclic systems.9 Transition metal complexes with thioether and phosphorus donor macrocycles are also known.2... 

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