TY - JOUR
T1 - Metal-stabilized rare tautomers of nucleobases. 5. Iminooxo tautomer of cytosine coordinated to Pt(II) with metal and nucleobase in syn and anti orientations
AU - Pichierri, F.
AU - Holthenrich, D.
AU - Zangrando, E.
AU - Lippert, B.
AU - Randaccio, L.
PY - 1996/10
Y1 - 1996/10
N2 - A PtII complex containing N4 bound neutral 1-methylcytosine (1-MeC), trans-[Pt(NH3)2(1-MeC-N4)2](ClO 4)2 (5), has been prepared and characterized by X-ray analysis. The complex contains the rare iminooxo tautomer form of the cytosine nucleobase. PtII binding is through the exocyclic N4 position of the nucleobases, with Pt and the N3 positions in a syn orientation. As a consequence, the proton at N3 is pointing toward the heavy metal, thereby allowing an agostic Pt⋯HN interaction. Formation of 5 is achieved via oxidation of the linkage isomer trans-[Pt(NH3)2(1-MeC-N3)2]2+ (1) to a PtIV species (2), followed by metal migration to N4, and subsequent reduction to PtII. This process is a text-book example for a redox-assisted metal migration at a heterocyclic ligand. The existence of various rotamers of 5 in aqueous solution is evident from 1H NMR spectroscopy. The possible role of these rotamers of the metalated rare tautomer, and in particular of those having Pt and the N3 position in an anti arrangement, with regard to base mispairing is discussed.
AB - A PtII complex containing N4 bound neutral 1-methylcytosine (1-MeC), trans-[Pt(NH3)2(1-MeC-N4)2](ClO 4)2 (5), has been prepared and characterized by X-ray analysis. The complex contains the rare iminooxo tautomer form of the cytosine nucleobase. PtII binding is through the exocyclic N4 position of the nucleobases, with Pt and the N3 positions in a syn orientation. As a consequence, the proton at N3 is pointing toward the heavy metal, thereby allowing an agostic Pt⋯HN interaction. Formation of 5 is achieved via oxidation of the linkage isomer trans-[Pt(NH3)2(1-MeC-N3)2]2+ (1) to a PtIV species (2), followed by metal migration to N4, and subsequent reduction to PtII. This process is a text-book example for a redox-assisted metal migration at a heterocyclic ligand. The existence of various rotamers of 5 in aqueous solution is evident from 1H NMR spectroscopy. The possible role of these rotamers of the metalated rare tautomer, and in particular of those having Pt and the N3 position in an anti arrangement, with regard to base mispairing is discussed.
KW - Cytosine
KW - Rare iminooxo tautomer
KW - Syn and anti arrangement
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U2 - 10.1007/s007750050076
DO - 10.1007/s007750050076
M3 - Article
AN - SCOPUS:0002735886
SN - 0949-8257
VL - 1
SP - 439
EP - 445
JO - Journal of Biological Inorganic Chemistry
JF - Journal of Biological Inorganic Chemistry
IS - 5
ER -