Analogues of Cis- and Transplatin with a Rich Solution Chemistry: cis-[PtCl2 (NH3 )(1-MeC-N3)] and trans-[PtI2 (NH3 )(1-MeC-N3)].
Mono(nucleobase) complexes of the general composition cis-[PtCl2 (NH3 )L] with L=1-methylcytosine, 1-MeC (1 a) and L=1-ethyl-5-methylcytosine, as well as trans-[PtX2 (NH3 )(1-MeC)] with X=I (5 a) and X=Br (5 b) have been isolated and were characterized by X-ray crystallography. The Pt coordination occurs through the N3 atom of the cytosine in all cases. The diaqua complexes of compounds 1 a and 5 a, cis-[Pt(H2 O)2 (NH3 )(1-MeC)](2+) and trans-[Pt(H2 O)2 (NH3 )(1-MeC)](2+) , display a rich chemistry in aqueous solution, which is dominated by extensive condensation reactions leading to μ-OH- and μ-(1-MeC(-) -N3,N4)-bridged species and ready oxidation of Pt to mixed-valence state complexes as well as diplatinum(III) compounds, one of which was characterized by X-ray crystallography: h,t-[{Pt(NH3 )2 (OH)(1-MeC(-) -N3,N4)}2 ](NO3 )2 ⋅2 [NH4 ](NO3 )⋅2 H2 O. A combination of (1) H NMR spectroscopy and ESI mass spectrometry was applied to identify some of the various species present in solution and the gas phase, respectively. As it turned out, mass spectrometry did not permit an unambiguous assignment of the structures of +1 cations due to the possibilities of realizing multiple bridging patterns in isomeric species, the occurrence of different tautomers, and uncertainties regarding the Pt oxidation states. Additionally, compound 1 a was found to have selective and moderate antiproliferative activity for a human cervix cancer line (SISO) compared to six other human cancer cell lines.
Fakultät Chemie und Chemische Biologie (CCB), Technische Universität Dortmund, Otto-Hahn-Str. 6, 44221 Dortmund (Germany), Fax: (+49) 231-755-3797.
Sabine
S
Siebel
Physikalische Chemie I, Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen (Germany).
Claudia
C
Dammann
Departamento de Química Inorgánica, Instituto de Síntesis Química y, Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, 50009 Zaragoza (Spain).
Pablo J
PJ
Sanz Miguel
Physikalische Chemie I, Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen (Germany).
Thomas
T
Drewello
Fakultät Chemie und Chemische Biologie (CCB), Technische Universität Dortmund, Otto-Hahn-Str. 6, 44221 Dortmund (Germany), Fax: (+49) 231-755-3797.
Gunnar
G
Kampf
Fakultät Chemie und Chemische Biologie (CCB), Technische Universität Dortmund, Otto-Hahn-Str. 6, 44221 Dortmund (Germany), Fax: (+49) 231-755-3797.
Natascha
N
Teubner
Pharmazeutische/Medizinische Chemie, Institut für Pharmazie der Ernst-Arndt-Universität Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17487 Greifswald (Germany).
Patrick J
PJ
Bednarski
Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland).
Eva
E
Freisinger
Fakultät Chemie und Chemische Biologie (CCB), Technische Universität Dortmund, Otto-Hahn-Str. 6, 44221 Dortmund (Germany), Fax: (+49) 231-755-3797. bernhard.lippert@tu-dortmund.de.
Bernhard
B
Lippert
1-methylcytosine; condensation reactions; diplatinum(III); mass spectrometry; platinum