Catalytic oxidations using ruthenium porphyrins - Advances in Catalytic Activation of Dioxygen by Metal Complexes - page 54

consistent with ( 27 ) being the bis(imido) species and
indeed a corresponding complex has been isolated and
characterized by NMR in the reaction of and
( 27 ) was also synthesized from oxidation of by
Formation of the bis-imido species implies a net loss of both H-atoms
attached to the N-atom of the amine (to give rather than one H-atom
from each of the N- and Most relevant to this is the interesting,
observed isomerization of the bis(imine) species to the
bis(imido) species in benzene at ambient conditions
during the oxidation of by which is
stoichiometric and forms stepwise the Ru(TMP)(amine)(imine) and then
Ru(TMP)(imine) 2 species (eq. 41); water and/or Ru species may play a role
in such isomerization. Attempts to make

species directly

from have not yet been successful. Other evidence for the
bis(imido) formulation for ( 27 ) includes its reaction with which
displaces the imido (or nitrene) moieties to generate the bis(amine) complex
and a polymeric nitrene product 197 . Related nitrene transfer reactions from
and (X = H, Cl, I, Me) to
pyridine and tertiary phosphines, respectively, have been demonstrated (see
below). Substitution of the imido ligand in (porp = TTP,
4-C1-TPP) by to generate has also been reported
(see below) 200 . Identification of ( 26 ) is less definitive: most likely it is the
oxo-imido species as corresponding species have

been characterized (see below).
For the system, data for the ( 26 ) and ( 27 )
intermediates were quite different, and were more consistent with them
being the mixed imine/amine species
(Me)Ph] and the bis(imine) respectively 197 . The
chemistry of systems differentiated by a Ph vs. Me substituent thus appear to
be remarkably different. In some systems with water added initially (prior to
its formation as a co-product), significant amounts of were

seen 197 .
Mixed Ru(II)-amine/imine complexes of the type

have been isolated from the reaction of
= the dianion of the chiral 10,15,20-tetrakis[o-(2-
methoxy-2-phenyl-3,3,3-trifluoropropanolamino)phenyl]porphyrin) with

esters 198,202,203 . For example, reaction of the methyl ester of excess