- Alkyl-substitution effect of the diamine on coordination geometry and ligand-field strength of niekel(ii) mixed-ligand complexes containing n-alkylethylenediamine, acetylacetonate, and nitrate ligands
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Structures and spectral properties have been investigated for nickel(TI) mixed-ligand complexes, [Ni(Me4en)-(acac)(N03)] (1), [Ni(EtMe 3en)(acac)(NO3)] (2), [Ni(asym-Et2Me2en)(acac) (NO3)] (3), [Ni(Et
- Shirase, Hitoshi,Saito, Mariko,Machiko, Arakawa-Itoh,Fukuda, Yutaka
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experimental part
p. 230 - 235
(2009/05/30)
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- Transalkylation Reaction. Homogeneous Catalytic Formation of C-N Bonds
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We have performed kinetic and mechanistic studies on homogeneous ruthenium-catalyzed transalkylation of tertiary amines.From these studies we have derived a kinetic expression for transalkylation catalysis based on initial reaction rates.We find that transalkylation proceeds most efficiently in alcoholic solvents (e.g., MeOH or EtOH), under a slight pressure of CO, with a mixed-metal, iron-ruthenium catalyst.The mechanism appears to be in one which a metal cluster of at least two and most probably three atoms binds the amine through insertion into an α C-H bond to give a metallazacyclopropane or metal-iminium complex.Nucleophilic attack by free amine on the complex, or an immediate derivative, follows, and subsequent rearrangement of the intermediate formed gives transalkylation products.The catalyst system has been tested as a synthetic tool for the oligomerization and cyclization of tertiary diamines.These preliminary studies have been quite succesful.Thus, N,N,N',N'-tetramethylethylenediamine can be transformed into Me3N and N,N'-dimethylpiperazine with good conversion and high selectivity.N,N,N',N'-Tetraethylethylenediamine can be transformed into Et3N and the linear, perethyl, ethylenediamine dimer, trimer, tetramer, and pentamer with excellent conversion.
- Wilson, Robert B.,Laine, Richard M.
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p. 361 - 369
(2007/10/02)
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