ISMSC 2007 - Università degli Studi di Pavia

PSB 7
Properties of metal complexes of a new dioxadiaza macrocycle containing a
dibenzofuran unit and acetate pendant arms
Pedro Mateus a , Judite Costa c , Feng Li a , Rita Delgado a,b
a Instituto de Tecnologia Química e Biológica, UNL, Apartado 127, 2781-901 Oeiras, Portugal.
b Instituto Superior Técnico, Departamento de Química, Av. Rovisco Pais, 1049-001 Lisboa,
Portugal.
c Faculdade de Farmácia de Lisboa, Av. das Forças Armadas, 1600 Lisboa, Portugal
A number of polyoxapolyazamacrocycles with a variety of functional pendant side-arms on the
nitrogen atoms has been prepared in the last two decades. [1] Macrocycles containing
carboxylate or/and phosphonate pendant arms have widely been studied for the application of
their paramagnetic lanthanide complexes as contrast agents in magnetic resonance imaging
(MRI) of soft tissue, or as radiopharmaceutical drugs for tumour imaging and therapy. [2],[3]
A new dioxadiaza macrocyclic ligand containing a rigid
dibenzofuran group (DBF) [4] and bearing two acetate
O
OH
N
O
O O
N
ac 2[17](DBF)N 2O 2
HO
O
pendant arms, ac2[17](DBF)N2O2, has been synthesized
in good yield by condensation of the parent amine with
potassium bromoacetate, in aqueous basic solution.
The protonation constants of ac2[17](DBF)N2O2 and its
stability constants of complexes with divalent 1 st row
transition metal and trivalent lanthanide cations were
determined at 298.2 K in aqueous solution and at ionic
strength 0.10 mol dm -3 in NMe4NO3. The first two
protonation constants, corresponding to the protonation
of the two amine centres within the macrocycle, are lower
than expected for secondary amines due to the inductive effect of the nearby ether oxygen
atoms and the electron withdrawing effect of the DBF group. The stability constants revealed a
preference of ac2[17](DBF)N2O2 for larger metal ions.
[1] R. D. Hancock, H. Maumela and A. S. Sousa, Coord. Chem. Rev., 1996, 148, 315-347.
[2] S. Liu, Chem. Soc. Rev., 2004, 33, 445-461.
[3] F. Marques, L. Gano, M. P. Campello, S. Lacerda, I. Santos, L. M. P. Lima, J. Costa, P.
Antunes and R. Delgado, J. Inorg. Biochem., 2006, 100, 270-280.
[4] F. Li, R. Delgado, A. Coelho, M. G. B. Drew and V. Félix, Tetrahedron, 2006, 62, 8550-8558.
The authors acknowledge the financial support from Fundação para a Ciência e Tecnologia (FCT) and
POCI, with coparticipation of the European Community fund FEDER (Project n. POCI/QUI/56569/2004).
PSB 8
The cleavage of cyclic substituents in derivatives of closo-decaborate anion
by diaza-crown-ether
E.Matveev, K.Zhizhin, N.Kuznetsov
Kurnakov Institute of General and Inorganic Chemistry, RAS,
31, Leninsky prosp., GSP-1, Moscow, 119991, zhizhin@igic.ras.ru
Moscow State Academy of Fine Chemical Technology (MIFCT)
86, Vernadsky prosp., Moscow, 119571
The number of numerous researches a reactions of cleavage of cyclic sustituents in derivatives
of closo-decaborate anion with oxonium groups are discussed [1-4].
Here we report about the reactions of cleavage of cyclic substituents in anion B10H10O2C4H8 - by
diaza-crown-ethers. It was showed that as result of reaction the formation of alkoxy spacer
chain occurs with the subsequent connection of diaza-crown-ether. Compounds were isolated
as the complexes with ions of alkali metals. In more severe conditions the participation of
already attached macrocyclic substituent occurs in the reaction of cleavage of another anion
B10H10O2C4H8 -
with formation of derivative having the structure of
B10H9O(CH2)2O(CH2)2NC12H24N(CH2)2O(CH2)2OB10H9 4- , in that two borane clusters are
connected via alkoxy chains and diaza-macrocyclic group, with cation of metal coordinating in
its cycle.
Scheme of described reactions is presented below:
Produced compounds can act as polydental ligands, at the same time the coordination can be
2– O
2–
2–
O
O O N
O O N
2–
O
O
O
O
K K
O
O
O
O
NH
N O O
carried out both due to atoms of oxygen and nitrogen, and due to participation of the unusual
donor centers – cluster anions, possessing ability to form three-central bonds of M-H-B with
metal.
Compounds were characterized by IR-, 11 B – NMR - and ESI - spectra.
This work was supported by RFBR (grants no. 05-03-32885 and 07-03-0000552) and the
Council for grants of the President of the Russian Federation for support of young scientists
(grants no. NSh-4895.2006.3, -4987.2006.3).