Reactions of fluorenylidene nitrile ylides with (salen)metal complexes

Abstract

Nitrile ylides of fluorenylidene (RR'C--N+C-R": R" = CH3 or C6H5; R, R' = CI2H8) serve as carbene equivalents in reactions with (salen)metal complexes (salen = AUV'-ethylenebis(salicylideneaminato)) of first-row transition metals in acetonitrile or benzonitrile solvents. The microscopic rate constants for these reactions were obtained directly by flash photolysis experiments and were found to depend upon the nature, oxidation state, and ligation of the metal. Oxo(salen)chromium(V) triflate reacts with a rate constant close to the diffusional limit to form (salen)chromium(III) triflate and fluorenone. The reactivities of (salen)metal(Ill) cations are lower and decrease in the order V > Cr > Mn > Fe. The reactions of the ylides with metal(III) cations apparently form metallocarbenes or related species, and products resulting from carbene insertion into a metal-ligand bond (as identified for M = Cr) ultimately are obtained.

A new Schiff base copper (II) complex: bis[N-(4-hydroxysalicylidene)-N′,N′-diethylethylenediamine-κ2N,O]bis[(oxalato-κ2O,O′)copper(II)] dihydrate

“…dioxygen binding, oxygen utilization etc. In order to emulate the biological activity of metalloproteins, particularly their active sites, various model metal complexes containing Schiff base ligands have been synthesized and studied for their dioxygen uptake (McLendon & Martell, 1976;Niederhoffer et al, 1984;Smith & Pilbrow, 1981;Tovrog et al, 1976;Martell & Sawyer, 1988;Busch & Alcock, 1994) and oxidative catalysis (Holm, 1987;Srinivasan et al, 1986;Dixit & Srinivasan, 1988;Rihter et al, 1993;SriHari & Masnovi, 1990). Recently, our group has studied the synthesis and the magnetic properties of Schiff base complexes (Bian, Gu et al, 2003;Bian, Xu et al, 2003a,b;Bian et al, 2004).…”

A new Schiff base–copper(II) complex: [N-(2-hydroxyethyl)-N′-(2-oxidobenzylidene)ethylenediamine-1κ4O,N,N′,O′][μ-N-(2-oxidobenzylidene)-N′-(2-oxidoethyl)ethylenediamine-1κO:2κ4O,N,N′,O′]dicopper(II) perchlorate methanol solvate

“…This interest is partly due to the relevance of these compounds as active site structures of metal proteins and enzymes (Karlin & Tyeklar, 1993;Jun & True, 1990), and partly because of attempts to understand the relationship between the structure and the magnetic properties (Gatteschi et al, 1984;Kahn, 1985Kahn, , 1987Doman et al, 1990;Kawato et al, 1992;Kavlakoglu et al, 2000). In order to emulate the biological activity of metalloproteins, particularly their active sites, various model metal complexes containing Schiff base ligands have been synthesized and studied for their dioxygen uptake (McLendon & Martell, 1976;Niederhoffer et al, 1984;Smith & Pilbrow, 1981;Tovrog et al, 1976;Martell & Sawyer, 1988;Busch & Alcock, 1994) and oxidative catalysis (Holm, 1987;Srinivasan et al, 1986;Dixit & Srinivasan, 1988;Rihter et al, 1993;Srihari & Masnovi, 1990). Recently, our group has studied the synthesis and the magnetic properties of Schiff base complexes (Bian, Gu et al, 2003;Bian, Xu et al, 2003a,b;Bian et al, 2004).…”