Resonance Raman spectra of adriamycin and aclaciwmycin A were examined in thew H,O and D,O solutions. These spectra appear totally different from each other, but the difierences are found to be similar to those between 1,4 and l,Whydroxyanthraquinone, which are considered to be model chromophores of adriamycin and aclacinomycin, respectively. Surface-enhanced resonance Raman spectra of these two drugs were also compared by the use of silver sols. The effects of DNA binding on the resonance Raman spectra are also significantly different for these two drugs. Adriamycin was found to be intercalated in the CpG (or GpC) site of the DNA duplex, but aclacinomycin in the TpA (or APT) site. Most of the differences in the spectra and sequence specificity are explained in terms of the molecular structures of their chromopbores, i-e. in the adriamycin chromophore (1,4 dihydroxyanthraquinone) two OH groups are hydrogen bonded to different C=O groups, whereas in the aclacinomycin chromophore (1,S-dihydroxyanthraquiwne) two OH groups form hydrogen bonds with the same C=O group, leaving the other C -0 group free from any intramolecular hydrogen bonding.

Cobalt(II), nickel(II), and copper(II) complexes with dioximes substituted by BF2- and B(C2H5)2-groups for bridging hydrogen atoms were prepared. The BF2-substitution caused a red-shift of d-d band and increase of g⁄⁄-value for copper(II) complexes and positive shift of polarographic half wave potential of nickel(II) complexes. In the case of the B(C2H5)2-substituted complexes, such variations were not observed. The BF2-substituted cobalt(II) complexes are stable under an open atmosphere at room temperature in a solid state and in a DMF solution. These were interpreted in terms of the electron-withdrawing ability of BF2-group in the ligand.

A new series of binuclear copper(II) complexes, [Fsal(=NenNR2)2Cu2X]2+ (R=Me and Et, X=Cl, Br, and OH), were synthesized, where Fsal(=NenNR2)2 indicates the Schiff base prepared from 2,6-diformyl-4-methylphenol and N,N-dialkylethylenediamine (alkyl=methyl(Me) and ethyl(Et)). Two copper(II) ions are connected with the phenolic oxygen and X. The complexes obtained were characterized by elemental analyses, infrared and visible spectra, molar conductivities in methanol, ESR spectra and magnetic susceptibilities. It was found that the stability of the complexes decreases in the order X=OH>>Br>Cl. It was concluded from cryomagnetic measurements that the effect of the bridging group X on spin-coupling decreases in the order OH>>Br>Cl.

The Raman spectra of distamycin and its complex with DNA were examined in both H,O and D,O solutions. To facilitate band assignments, Raman spectra of several small model compounds of distamycin were also obtained. On binding to DNA, tbe C -0 stretching band at 1620 cm-' (amide I band) of distamycin was shifted upwards by 14 Ern-', whereas a strong pyrrole-ring stretching band at 1437 cm-' was shifted downwards by 7 em-' in H,O. In addition, most of the Raman bands including amide I, I1 and 111 became narrower and sharper on binding to DNA. These results indicate that, in the free state, the dihedral angles around the C -C and N -C bonds connecting the pyrrole ring and the peptide chain of distamycin fluctuate near 0' (coplanar configuration), whereas in the bound state these angles are fixed and markedly shifted from Oo. Previous x-ray and NMR studies on distamycin (netropsin)-DNA complexes show that such deviations occur when these drug molecules are bound in the minor groove of DNA. Molecular distortion of distamycin caused by interaction with other polynucleotides has also been elucidated by using such spectral characteristics as diagnosis.