G. Fusch et al., HETERONUCLEAR MU-1-METHYLCYTOSINATO-N3,N4 COMPLEXES CONTAINING VERY SHORT PT-]CU DATIVE BONDS, Inorganica Chimica Acta, 252(1-2), 1996, pp. 167-178
A series of mixed Pt-II,Cu-II complexes derived from trans-[a(2)Pt(1-M
eC-N3)(2)](2+) (a = NH3 or CH3NH2; 1-MeC = 1-methylcytosine, coordinat
ed to Pt via N3) and of general formula trans-[a(2)Pt(1-MeC(-)-N3,N4)(
2)CuL](n+) with L = mu-CO32- (1, 2), OH- (3), NH3,H2O (4), 1-MeC-N3 (5
), 9-EtGH-N7,H2O (6) have been isolated and characterized by X-ray ana
lysis. In all compounds a trans-a(2)Pt(II) entity is bound to two cyto
sine nucleobases via N3 sites each, whereas a Cu-II is bound to two mo
nodeprotonated N4 sites. In all cases Pt-II represents a ligand of Cu-
II, which either displays a distorted square-planar (1, 2, 3, 5) or a
pentacoordinate environment (4, 6). Pt-II-Cu-II distances are very sho
rt, ranging from 2.49 to 2.56 Angstrom in the six compounds. EPR spect
ra of frozen solutions have been examined in several cases. They appea
r, at least for 4a and 5, to be consistent with Pt-Cu hyperfine intera
ctions rather than the presence of two different Cu-only species.