H. Furutachi et al., Oxygenation of heterodinuclear di(mu-phenoxo) Co(II)M(II) (M = Mn, Fe or Co) complexes having a "Co(salen)" entity in a macrocyclic framework, J CHEM S DA, (13), 1999, pp. 2197-2203
Citations number
72
Categorie Soggetti
Inorganic & Nuclear Chemistry
Journal title
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
Heterodinuclear di(mu-phenoxo) (CoMII)-M-II complexes [CoM(L)(AcO)]ClO4 (M=
Mn 1, Fe 2 or Co 3) and [CoM(L)(NCS)]ClO4 (M=Mn 4, Fe 5 or Co 6) have been
obtained where L2- is a heterodinucleating macrocycle derived by the 2:1:1
condensation of 2,6-diformyl-4- methylphenol, ethylenediamine and diethylen
etriamine and has a "salen"-like N2O2 metal-binding site and a "saldien"-li
ke N3O2 site sharing the phenolic oxygens. The CoM(AcO) complexes 1 and 3 s
how reversible oxygenation at 0 degrees C in dmf, whereas 2 is irreversibly
oxidized under the same conditions. The structures of the dioxygen adducts
of 1 and 3 have been determined by X-ray crystallography. In that of 1, [{
CoMn(L)(AcO)}(2)(O-2)][ClO4](2). 4CH(3)CN oxy-1, the Co resides in the "sal
en" site and the Mn in the "saldien" site. An exogenous acetate group bridg
es the two metal ions in the eta(1):eta(1) mode together with the two pheno
lic oxygens. The peroxo group bridges two {CoMn(L)(AcO)} molecules at the C
o forming a Co-O-O-Co linkage. The peroxo O(1)-O(2) bond distance is 1.416(
5) Angstrom and the Co(1)... Co(2) intermetallic separation is 4.359(1) Ang
strom. The geometry about the Co is pseudo octahedral with a peroxo oxygen
and an acetate oxygen at the axial sites and the Mn has a distorted six-co-
ordination. The dioxygen adduct of 3, [{Co-2(L)(AcO)}(2)(O-2)][ClO4](2). 4C
H(3)CN oxy-3, is isomorphous with oxy-1: the peroxo O(1)-O(2) bond distance
is 1.415(4) Angstrom and the Co(1)... Co(3) intermetallic separation is 4.
3527(8) Angstrom. Within the CoM(NCS) complexes 4-6, 4 shows reversible oxy
genation at -30 degrees C, whereas irreversible oxidation is observed for 5
and 6.