Metal-Templated Ligand Architectures for Trinuclear Chemistry: Tricopper Complexes and Their O2 Reactivity Theodor Agapie (Division of Chemistry and Chemical Engineering, Caltech)
Dioxygen reduction to water is of interest in fuel cell applications. To model the active site of tricopper oxygenases, a trinucleating framework was Dioxygen reduction: designed by templation of a heptadentate ligand around yttrium and 2H2O O2 + 4e- + 4H+ lanthanides. The generated complexes orient three sets of two or three Ndonors each for binding additional metal centers. Addition of three equivalents of copper(I) leads to the formation of a tricopper(I) species. N Reaction with dioxygen at low temperatures generates a µ3,µ3-dioxoN N N N tricopper complex based on spectroscopic analysis. Characterization and N N reactivity studies related to dioxygen activation at tricopper cores were N N performed. Regeneration of the tricopper(I) species was accomplished upon N reduction with thiophenol. O + YR (THF) N
3
2
HO N
N
R=CH2SiMe3
O
N N
3 CuOTf
3
O
Y
N
N
MeCN
L=MeCN
N N CuL N
2
N
N CuL
LCu
N
N
+3
N
N
N N
NO N N Cu NCu Cu N N O N
O2, -78 oC OO O Y N N N N
Monocopper variants do not display similar O2 reactivity.
EtCN
4 ArSH -2 ArSSAr -2 H2O
OO O N Y N N N
+3
