Cytosine Complexes with Copper(II) Perchlorate

The replacement of chlorides by cytosines in copper(II) complexes containing guanidine derivatives

“…These activities have guided us to prepare copper(II) complexes containing a CuN 2 Cl 2 chromophore analog to cisplatin and then to study their interactions with DNA nucleobases. Several studies have mainly focused on the direct interaction of metal salts, where M = Cu, Rh, Cd, Mn or Co, with the cytosine nucleobase and its derivative 1-methylcytosine [12][13][14][15][16][17][18][19], but not the direct nucleobase replacement of the anionic ligands on metal complexes like the cisplatin system. However, Reedijk and coworkers have studied on interactions of the octahedral ruthenium(II) complexes [cis-Ru(bpy) 2 Cl 2 ] [20] and [a-Ru(azpy) 2 -(NO 3 ) 2 ] [21] (bpy = 2,2 0 -bipyridine and azpy = 2-(phenylazo)pyridine) with 9-ethylguanine, 9-methylhypoxanthine and guanosine, which replace only one of the two anionic ligands to yield the monofunctional binding adducts.…”

“…Besides, other advantages of this complex system are that (i) complexes 1 and 2 are similar to cisplatin in that they contain the same MN 2 Cl 2 (M = Cu or Pt) chromophore; (ii) the L 1 and L 2 ligands are an N,N-bidentate ligand which will chelate to a copper center and give a more stable complex; (iii) this ligand system also results a compound in cis-isomer, just like cisplatin; and (iv) hence, one site of complexes 1 and 2 is blocked by the L 1 and L 2 ligands and another site is situated by two labile groups (Cl À ) which will be easily replaced by nucleobases such as cytosine. It was found that the predominant metal binding site of cytosine nucleobase is the nitrogen atom N(3) (Scheme 2) [11,12,14,15,17,23,24]. In addition, the secondary interaction between copper and the O(2) exocyclic carbonyl group of cytosine also exists in a few cases [16,25,26].…”

Unexpected cytosine–AuCl4− interaction under electrospray ionization mass spectrometry conditions—Formation of cytosine–Au(I) complexes

“…Interaction between cytosine and Cu 2þ leads to the formation of a number of complexes interesting from the structural point of view and their structures have been studied in details by crystallographic, spectroscopic, and electrochemical methods. [1][2][3][4][5][6][7][8][9][10] The studies of cytosine complexes with silver cation have shown the formation of a very stable C-Ag þ -C complex (i-motif-like complex). In other words, Ag þ ions bind to C-C mismatches and form C-Ag þ -C complexes in DNA duplexes.…”