Synthesis and spectroscopic properties of anhydrotetracyclineplatinum(II)dichloride

The reaction of tetracycline with K2PtCl4 in glacial acetic acid leads to the dehydration of tetracycline to anhydrotetracycline (ahtc) which coordinates as a bidentate ligand to the PtCl2 moiety. The composition of Pt(ahtc)Cl2 is confirmed by elemental analysis and mass spectrometry. On the basis of the electronic spectra it is suggested that the coordination takes place at the A ring of ahtc while the BCD ring system is preserved as separate chromophore. It is characterized by a long-wavelength absorption and fluorescence which appear at λmax=428 and 550 nm, respectively, for the free ahtc ligand and λmax=425 and 550 nm for Pt(ahtc)Cl2.