TY - JOUR
T1 - New Hexaaza Macrocyclic Binucleating Ligands. Oxygen Insertion with a Dicopper(I) Schiff Base Macrocyclic Complex
AU - Menif, Rached
AU - Martell, Arthur E.
AU - Squattrito, Philip J.
AU - Clearfield, Abraham
PY - 1990
Y1 - 1990
N2 - Direct 2:2 condensation of isophthalaldehyde with diethylenetriamine produces a hexaaza 24-membered macrocyclic tetra Schiff base in good yield. The crystal structure of an isomeric form of the Schiff base is reported. Crystal data for N6C24H30·½MeOH: C2/c,a = 17.283 (2) Å, b = 16.930 (2) Å, c = 17.953 (3) Å, β = 118.73 (2)°, V= 4607 (2) Å3, Z = 8, R(F) = 0.059 for 1538 observations (I > 3(σ(I)) and 289 variables. The amber binuclear Cu(I) complex of the tetraaza macrocyclic Schiff base combines with a molar equivalent of dioxygen to form a green binuclear Cu(II) complex, which contains a bridging hydroxide ion and, by oxygen insertion, a bridging phenolate donor. These results provide the first macrocyclic tyrosinase model. Hydrogenation of the Schiff base provides the corresponding saturated hexaaza macrocyclic ligand. The protonation constants of the reduced macrocycle, as well as the binding constants of its mononuclear and binuclear Cu(Il) complexes, have been determined potentiometrically.
AB - Direct 2:2 condensation of isophthalaldehyde with diethylenetriamine produces a hexaaza 24-membered macrocyclic tetra Schiff base in good yield. The crystal structure of an isomeric form of the Schiff base is reported. Crystal data for N6C24H30·½MeOH: C2/c,a = 17.283 (2) Å, b = 16.930 (2) Å, c = 17.953 (3) Å, β = 118.73 (2)°, V= 4607 (2) Å3, Z = 8, R(F) = 0.059 for 1538 observations (I > 3(σ(I)) and 289 variables. The amber binuclear Cu(I) complex of the tetraaza macrocyclic Schiff base combines with a molar equivalent of dioxygen to form a green binuclear Cu(II) complex, which contains a bridging hydroxide ion and, by oxygen insertion, a bridging phenolate donor. These results provide the first macrocyclic tyrosinase model. Hydrogenation of the Schiff base provides the corresponding saturated hexaaza macrocyclic ligand. The protonation constants of the reduced macrocycle, as well as the binding constants of its mononuclear and binuclear Cu(Il) complexes, have been determined potentiometrically.
UR - http://www.scopus.com/inward/record.url?scp=33751554242&partnerID=8YFLogxK
U2 - 10.1021/ic00348a028
DO - 10.1021/ic00348a028
M3 - Article
AN - SCOPUS:33751554242
VL - 29
SP - 4723
EP - 4729
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 23
ER -