| Abstract
| - Three new derivatives of the cytotoxic azole-bridged dinuclear platinum(II) complex [{cis-Pt(NH3)2}2(μ-OH)(μ-pz)][NO3]2 (1) have been prepared and structurally characterized. Their formulas are [{cis-Pt(NH3)2}2(μ-OH)(μ-1,2,3-ta)][NO3]2 (2) (1,2,3-ta = 1,2,3-triazolate), [{Pt(R,R-dach)}(μ-OH)(μ-pz){Pt(S,S-dach)}][NO3]2 (3) (dach= 1,2-diaminocyclohexane, pz = pyrazolate), and [{Pt(R,R-dach)}(μ-1,2,3-ta)2{Pt(S,S-dach)}][NO3]2 (4). Thecompounds were characterized by 1H, 13C, and 195Pt NMR spectroscopy, and elemental analysis, and their crystalstructures were determined. Relevant data for 2: triclinic, space group P1̄, a = 8.5225(15) Å, b = 9.1977(18) Å,c = 9.9771(7) Å, α = 66.988(10)°, β = 75.423(9)°, γ = 67.321(13)°, Z = 2. 3: orthorhombic, space groupPca21, a = 17.7653(3) Å, b = 12.4076(3) Å, c = 10.7091(3) Å, Z = 4. 4: orthorhombic, space group Pbca, a= 13.8944(1) Å, b = 17.8668(1) Å, c = 20.7647(2) Å, Z = 8. In the crystal structures of 2, and 3, the intramoleculardistances between the two Pt atoms are 3.4411(6) and 3.4873(5) Å, and the dihedral angles between the platinumcoordination planes are 14.1(3) and 9.3(4)°, respectively. In 2, an intramolecular hydrogen bond is observedbetween N9 of the ammine ligand and the noncoordinated nitrogen atom (N3) of the triazole ring (N9···N3: 2.962(10) Å). 4 has a boat-form structure, and the two coordination planes cross at 83.64(10)°. A cytotoxicityassay of these dinuclear platinum(II) compounds on human tumor cell lines was performed. In most of the celllines, 1 and 2 showed much higher cytotoxicity than those of cisplatin. On the other hand, 3 was found to bemoderately active, and 4 was found only marginally cytotoxic. Implications of these findings are discussed in thecontext of a structure−activity relationship.
- Three new azole-bridged dinuclear platinum(II) complexes, have been prepared and structurally characterized. Their formulas are [{cis-Pt(NH3)2}2(μ-OH)(μ-1,2,3-ta)][NO3]2 (2) (1,2,3-ta = 1,2,3-triazolate), [{Pt(R,R-dach)}(μ-OH)(μ-pz){Pt(S,S-dach)}][NO3]2 (3) (dach = 1,2-diaminocyclohexane, pz = pyrazolate), and [{Pt(R,R-dach)}(μ-1,2,3-ta)2{Pt(S,S-dach)}][NO3]2 (4). The compounds were characterized by NMR spectroscopy and elemental analysis, and their crystal structures were determined. Compound 2 shows much higher cytotoxicity than cisplatin.
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