Research and Principal Research Interests
in the Biochemical Reactions (BCR) group involves synthetic organic and
bioinorganic chemistry. In the bioinorganic area, our objective is to
a fundamental structural, spectroscopic, and mechanistic understanding
of copper protein active sites of biological and environmental
via the synthesis, characterization, and analysis of the reactivity of
model complexes. We are also interested in developing new models of key
intermediates in the catalytic cycles of non-heme diiron enzymes. The
goal of our research is to synthesize and characterize a variety of
complexes of different N-donor ligands, pyridine, amine, and so on.
Mechanism of Cytochrome c Oxidase
is to build a model compound of cytochrome c oxidase (CcO), which
contains a dinuclear metal site, a non-heme copper and a heme, as an
oxygen activation system. A hetero-bimetallic iron/copper complex
by a hybrid heme/non-heme ligand system is reported the first example
contains a m-peroxo bridge between the two metal ions. To seek the O2
mechanism in CcO, reactivity of the hetero-dinuclear Fe/Cu centers,
of the ligating axial imidazole, and the role of tyrosine crosslinked
imidazole in the enzymatic system have been investigated in detail in
have also been directed to modeling of other multi-nuclear
as typical oxygenation and/or oxidation catalysts which utilize
dioxygen and oxidize various organic molecules in good regio- and/or
Three types of ligands have been synthesized and characterization and
studies of the corresponding di- and multi-nuclear copper and iron
are now in progress: (i) Unsymmetric bidentate ligands consisting of
tri- and tetradentate metal-binding moieties, (ii) Tri-nucleating
for modeling of multi-copper enzyme active sites, and (iii)
bidentate ligands for asymmetric oxygenation reaction.
reactivity by 2-(2-pyridyl)ethylamine bidentate ligands”, M. Taki, S.
S. Nagatomo, Y. Tachi, T. Kitagawa, S. Itoh, and S. Fukuzumi, J.
Am. Chem. Soc., 124, 6367-6377 (2002).
ligand in copper(II) and zinc(II) complexes”, S. Yokota, Y. Tachi,
and S. Itoh, Inorg. Chem. 41, 1342-1344 (2002).
“Reactivity of Bis(μ-oxo)dicopper(III)
Complex toward External Substrates”, M. Taki, Y. Tachi, S.
and S. Itoh, J. Inorg. Biochem., 86, 449-449
“Modulation of Coordination
Chemistry in Copper(I) Complexes Supported by
Tridentate Ligands”, T. Osako, Y. Tachi, M. Taki, S. Fukuzumi,
S. Itoh, Inorg. Chem., 40, 6604-6609 (2001).
Cu-Fe Heterodimetallic Complexes as Models of Terminal Oxidases”, Y.
Naruta, Y. Tachi, T. Chishiro, A. E. Wigger, and F. Tani, J.
Inorg. Biochem., 86,
6. “A new
Ligand Carrying a Functional Group on the Carbon Framework. Synthesis
Characterization of a Linear Polymeric Copper(I) Complex”, S. Yokota, Y.
Tachi, N. Nishiwaki, M. Ariga, and S. Itoh, Inorg. Chem., 40,
Oxygenation of Sterically Hindered Tripyridine Ligands to Form
Cu(II) Complexes”, M. Kodera, Y. Tachi, T. Kita, H. Kobushi, Y.
Sumi, K. Kano, M. Shiro, M. Koikawa, T. Tokii, M. Ohba, and H. Okawa, Inorg.
Chem., 39, 226-234 (2000).
Reversible O2-Bindig of a Room Temperature Stable μ-η2:η2-Peroxodicopper(II)
Complex of a Sterically Hindered Hexapyridine Dinucleating Ligand”, M.
Kodera, K. Katayama, Y. Tachi, K. Kano, S. Hirota, S. Fujinami,
and M. Suzuki, J. Am. Chem. Soc., 121, 11006-11007
Complex Oxidatively Generated by a Reaction of Di-μ-hydroxodicopper(II)
Complex with Hydrogen Peroxide”, M. Kodera, Y. Tachi, S.
K. Katayama, H. Shimakoshi, K. Kano, K. Fujisawa, Y. Moro-oka, Y.
and T. Kitagawa, Chem. Lett., 5, 389-390 (1998).
of Various Phenols Catalyzed by Di-μ-hydroxodicopper(II)
Complexes of a Hexapyridine Dinuceating Ligand”, M. Kodera, H.
Shimakoshi, Y. Tachi, K. Katayama, and K. Kano, Chem. Lett.,