ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2006, Vol. 32, No. 4, pp. 276–281. © Pleiades Publishing, Inc., 2006.
Original Russian Text © G.M. Mamardashvili, B.D. Berezin, 2006, published in Koordinatsionnaya Khimiya, 2006, Vol. 32, No. 4, pp. 288–293.
Previously [1–5], we studied the reaction of some
porphyrins with amino acid and peptide complexes
being chelate salts with bi- and tridentate ligands.
This reaction can be regarded as a particular case of a
chelate-macrocyclic interaction considered in detail in
) and adenosine (
) form with
metals two types of com-
plexes, i.e., complexes with the bridging and mono-
dentate ligands. Neither the amino group in adenine
nor the hydroxyl group in adenosine act as the coordi-
nation center in complexes, and these bases do not
form chelate salts. The presence in complexes of che-
late salts or monodentate ligands, charged or
uncharged species, is determined, ﬁrst of all, by the
conditions of synthesis of these complexes: reacting
species, pH of a medium, the concentration ratio of the
metal ions and adenine [8–10].
The structures of solid adenine and adenosine com-
plexes are studied well today, whereas the states of
monodentate and bridging adenine and adenosine com-
plexes in solutions are studied poorly. The following
questions are still to be answered: which species are
formed during dissociation of monodentate and bridg-
ing metal adeninates and adenosinates, for example, in
DMSO and how deep is this process; what is the differ-
ence between dissociation of the complexes in DMSO
and in aqueous or alcohol media, and how the metal
nature affects the dissociation reaction.
The reaction of formation of metalloporphyrins is
peculiar in that it can be used as a model reaction when
studying a series of problems in general, organic, and
physical chemistries, including determination of states
of the metal salts MX
(M is the transition
is a solvent) in solutions [11–13]. The pos-
sibility of using reaction (1) (see below) as indicator
reaction when studying the states of salts in solutions
stems from unique coordinating properties of porphy-
). These properties specify constant composi-
tion of complexes (with a ratio of metal : porphyrin =
1 : 1); high stability of complexes, which nevertheless
strongly depends on the electronic structure and charge
of a cation; low rates of complexation reactions
between porphyrin and a metal salt that are easily mea-
sured by spectrophotometric method.
The reactions of complex formation of porphyrins
with different metal salts in polar solvents are classiﬁed
as follows : 1) reactions between inner-sphere com-
plexes; 2) reactions of replacement of the ligands
directly bonded to a metal ion by other ligands; 3) reac-
tions proceeding in one stage, when the porphyrin
ligand provides to a metal ion the electron pairs sufﬁ-
cient to ﬁll in its valence orbitals.
When reacting with the
-solvate of porphyrin, the
salt looses two molecules of a solvent to give
the polar transition state
Interaction of Porphyrins with Adenine
and Adenosine Complexes.
Effect of a Metal Nature
G. M. Mamardashvili and B. D. Berezin
Institute of Solution Chemistry, Russian Academy of Sciences, ul. Akademicheskaya 1, Ivanovo, 153045 Russia
Received June 14, 2005
—Reactions of complex formation of 5,10,15,20-tetraphenylporphine (
) and tetra-
) with adenine and adenosine complexes of
-metals in DMSO and ethanol
are studied. It was found that
reacts with Cu(II) and Hg(II) adeninates and adenosinates in DMSO, but
does not react with Zn(II), Co(II), and Cd(II) adeninates and adenosinates (with both bridging and monodentate
type of the ligand coordination).
enters the complex formation reaction with adeninates and ade-
nosinates of all studied metals in DMSO at almost equal rates. The states of adenine and adenosine complexes
metals in DMSO and ethanol are proposed on the basis of kinetic data obtained.