ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P40. Interaction Between Re(CO)3 Fragments and a PNA Monomer.
D. Donghi a , M. Panigati a , G. D’Alfonso a , G. Prencipe b , E. Licandro b , S. Maiorana b ,
L. D’Alfonso c
a
Dipartimento di Chimica Inorganica, Metallorganica, Università degli Studi di Milano, Via Venezian 21,
20133, Milano, Italy
e-mail: daniela.donghi@unimi.it
b
Dipartimento di Chimica Organica e Industriale, Università degli Studi di Milano, Via Venezian 21, 20133,
Milano;
c
Dipartimento di Fisica, Università di Milano-Bicocca, Piazza delle Scienze 6, 20126 Milano, Italy
Peptide nucleic acids (PNA) are mimics of DNA, with pseudo-peptide backbones based commonly on
N-(2-aminoethyl)-glycine, which show high binding affinity and specificity for DNA and RNA.[1] The
conjugation of organometallic complexes to biomolecules finds applications both in diagnostic and therapeutic
fields. The incorporation of Re(I) fragments into PNA fragments can offer a double advantage, due both to its
radiochemical [2] and photo-emitting properties. [3]
In this work we have investigated two different approaches for binding the thymine-PNA monomer with
Re(I)complexes.
We synthesized the novel compound [Re2(CO)6(µ-Cl)2(µ-4-COOH-pdz)], belonging to a recently developed
family of dimeric luminescent Re(I) complexes,[4] and conjugated it to the NH2 end of a thymine-PNA
monomer, obtaining the adduct shown in Figure. It exhibits photoluminescence with both one and two photon
excitation, but low quantum yield (~0.003) and short lifetime. Studies on the binding with the homo-thymine
PNA decamer are in progress, as well as attempts to synthesize ligands with a spacer between the pyridazine ring
and the COOH group, to increase lifetime and quantum yields.
A different conjugation approach involved coupling of the easily obtainable anionic dimer [Re2(CO)6(µ-OH)3] -
with a thymine-PNA monomer bearing a carboxylic acid function. The interaction gives an adduct, characterized
by NMR spectroscopy, in which the binding occurs through a bridging carboxylate group.
References:
[1] P.E. Nielsen, Editor Peptide Nucleic Acids: Protocols and Applications, Second Editions, Horizon
Bioscience, 2004, Wymondham, UK.
[2] R. Alberto, Coord. Chem. Rev., 901, 190 (1999).
[3] J. Zubieta, J.F. Valliant et al, J.Am. Chem. Soc., 126, 8598 (2004).
[4] D. Donghi, G. D'Alfonso, M. Mauro, M. Panigati, P. Mercandelli, A. Sironi, P. Mussini, L. D'Alfonso.,
Inorg. Chem., DOI: 10.1021/ic7023692 (2008).
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