M. Postel, F. Casabianca, Yanne Gauffreteau
Mar 17, 1986
Citations
0
Influential Citations
18
Citations
Journal
Inorganica Chimica Acta
Abstract
Abstract The synthesis and properties, with respect to oxygen transfer to olefins, of four peroxo Ti(IV) complexes of pyrazine- and pyridinedicarboxylic acids, are reported. The X-ray structure of Ti- [pz(COO)(COOH)](acac)(HMPA), 1 , was performed; it essentially revealed that the pyrazine ligands are non-bridging: the carboxylate group at the 2 position is deprotonated while the other carboxylate forms intramolecular hydrogen bonds. Strong stabilization of the peroxo moiety precluded oxygen transfer from 1 to organic substrates. On the other hand, pyrazine- and pyridine-2,5-dicarboxylic acids yielded polymeric compounds 2–4 where both carboxylate groups of the ligands are deprotonated. Complexes 2–4 epoxidize tetramethylethylene; the reactivity thus revealed is attributed to the breaking of the pyrazine or pyridine bridges in solution, which liberates a vacant site on the metal. Crystal data for 1 : C 23 H 46 N 8 O 10 P 2 Ti 2 , triclinic, a = 16.295(6), b = 15.247(6), c = 15.398(6) A, a = 90.36(2)°, β= 115.50(2)°, γ = 89.21(2)°; space group P 1, Z = 4.