451495-35-5Relevant articles and documents
Furfurylidene-imines as components of the oxidative coupling with CO2 at nickel(0) centers: Influence of the substituents on the structure of the resulting nickelacycles
Walther, Dirk,Kilian, Rainer,Schreer, Heike,Goerls, Helmar
, p. 851 - 862 (2008/10/08)
The oxidative coupling between benzaldehyd-N-furfurylidene-imine, CO2 und Ni(cod)2 results in THF or 1.4-dioxane in the formation of the organometallic macrocycle 1a, even if a large excess of Schiff base was used. 1a reacts with Ph3P under partial elimination of CO2 to form the tetranuclear complex 2, which contains two nickela-aziridine rings' linked with two nickelacyclic carbamates. Surprisingly, the protolysis of 1 followed by elimination of CO2 results in the formation of the organometallic product 3 which also contains a Ni-C bond in a (protonated) nickelaaziridine ring. Para-hydroxybenzaldehyd-N-furfurylidene-imine (B), CO2 und Ni(cod)2 react under oxidative coupling to form the nickelacycle 4, in which the monomeric metallacyclic units are connected by a hydrogen-bonded network to form a polymeric supramolecular system. Two of the Schiff bases B coordinate as N-donors at the NiII center, the third Schiff base acts as the substrate for CO2. Ferrocene-carbaldehyde-N-furfurylidene-imine forms in the presence of bipy the monomeric nickelacycle 22 containing the intact ferrocenyl unit. The solid-state structures of 2, 3, 4, and 22 were determinated by X-ray crystallography. Comparison of CO valence frequencies allows to indicate the coordination mode in nickelacycles with other Schiff bases.
