Platinum(II) complexes containing amine ligands

Pd2Ag triangle supported by two µ3-amidopyridine ligands

[Pd(tmeda)(Hampy-N1)(H2O)]2+ (tmeda=N,N,N',N'-tetramethylethylenediamine; Hampy=2-aminopyridine) forms in the presence of Ag+ at pH 8-9 a triangular Pd2Ag complex containing two deprotonated ampy- ligands. It has been crystallized and structurally characterized with nitrate anions and a second co-crystallized AgNO3, [{Pd(ampy)(tmeda)}2Ag(micro-NO3)2Ag(NO3)2]. The two amidopyridine ligands are triply bridging, binding to Ag+ in a monodentate fashion viaN1, and to two PdII centres in a micro2-bridging fashion via the monodeprotonated N2 position. The resulting four-membered Pd(ampy)2Pd metallacycle is syn-planar with Pd[dot dot dot]Pd separations of 3.0878(13) A. The Pd...Ag distances are 3.0879(14) A in (isosceles triangle). In solution (D2O), the two ampy- ligand in are non-equivalent as concluded from a detailed 1H NMR spectroscopic study and confirmed by a 13C NMR spectrum. Removal of Ag+ from, as achieved by addition of Cl-, causes cluster degradation and linkage isomerization of PdII(tmeda) from the exocyclic N2 to the endocyclic N1 position.

Platinum(II) complexes of 4-methoxy- and 4-chlorobenzoic acid hydrazides. Synthesis, characterization, and cytotoxic effect

The complexes [Pt(NH3)(pmbah)Cl2], [Pt(NH3)(pcbah)Cl2], [Pt(pmbah)2X2] and [Pt(pcbah)2X2] (pmbah = 4-methoxybenzoic acid hydrazide, pcbah = 4-chlorobenzoic acid hydrazide; X = Cl, Br, I) have been synthesized and characterized by elemental analysis, electric conductivity, 1H NMR, IR, and electronic spectra. A cis-square planar structure with hydrazide ligands coordinated via the NH2 groups has been proposed for these compounds. The complexes, but not the free ligands, have shown a strong growth inhibitory effect in Friend leukemia cells in vitro, most of which are more active than cisplatin.

Platinum (II) complexes of benzoic- and 3-methoxybenzoic acid hydrazides. Synthesis, characterization, and cytotoxic effect

The complexes [Pt(bah)2X2], [Pt(NH3)(bah)Cl2].0.5H2O, [Pt(mbah)2X2], and [Pt(NH3)(mbah)Cl2] (bah = benzoic acid hydrazide, mbah = 3-methoxybenzoic acid hydrazide; X = Cl, Br, I) have been prepared and characterized by elemental analysis, electric conductivity, IR, 1H NMR, and electronic spectra. A cis-square planar structure with hydrazide ligands coordinated via the NH2-groups has been proposed for these complexes. The complexes have shown a growth-inhibitory effect against Friend leukemia cells in culture comparable to that of the antitumor drug cisplatin.

Synthesis, characterization and anti-tumour testing of some platinum(II) amine complexes containing 1,1- and 1,2-cyclobutanedicarboxylate ligands

A series of new platinum(II) amine complexes containing 1,1- and 1,2-cyclobutanedicarboxylate ligands, cis-[PtA2(1,1-CBDCA)] (A = RNH2, where R = C2H5, n-C3H7, n-C4H9, n-C5H11, n-C6H13, c-C3H5, c-C5H9, c-C6H11; A2 = ethylenediamine, 1,3-diaminopropane), cis-[PtA2(1,2-CBDCA)] (A = NH3, RNH2 where R = CH3, C2H5, n-C3H7, n-C4H9, c-C3H5) and trans-[Pt(NH3)2(1,1-CBDCAH)2] (CBDCA, CBDCAH = dianion and monoanion of the dicarboxylic acid, respectively) have been synthesized by an improved route. These complexes are stable in aqueous solution and show good aqueous solubility. The [Pt(c-C3H5NH2)2(1,1-CBDCA)] can be isolated in white, grey and blue forms. The grey and blue forms exhibit ESR signals analogous to the so-called platinum blues. The existence of the blue form in aqueous solution is time and temperature dependent. Several of the complexes have been tested against leukaemia L1210 in male BDF mice and activity appears to decrease with the increase in length of the aliphatic chain (or increase in size of the alicyclic ring) of the primary amine. The Yoshida lymphoscarcoma screen, usually insensitive to platinum drugs, was found to respond well to [Pt(n-C4H9NH2)2(1,1-CBDCA)] in 5-day subcutaneously implanted tumours in female Wistar rats.