72151-35-0Relevant articles and documents
Multinuclear NMR study and crystal structures of complexes of the types cis- and trans-Pt(Ypy)2X2, where Ypy=pyridine derivative and X=Cl and I
Tessier, Christian,Rochon, Fernande D.
, p. 25 - 38 (1999)
Complexes of the types cis- and trans-Pt(Ypy)2X2 where Ypy is a methyl derivative of pyridine and X=Cl or I were studied by spectroscopic methods, especially by multinuclear NMR spectroscopy. In 195Pt MNR, the cis-dichloro compounds were observed between -1998 and -2021 ppm in CDCl3, while the trans compounds were found at slightly lower field, between -1948 and -1973 ppm. The diiodo species were observed at much higher field, between -3199 and -3288 ppm for the cis isomers and between -3122 and -3264 ppm for the trans isomers. In 1H NMR, the 3J(195Pt-1H) coupling constants are larger for the cis compounds (about 42 ppm) than for the trans isomers (about 33 ppm). In 13C NMR, the values of 3J(195Pt-13C) were also found to be larger for the cis complexes. There seems to be a slight dependence of the pKa values of the protonated ligands on the δ(Pt) chemical shifts. The presence of π-bonding between Pt and the pyridine ligands do not seem very important. The crystal structures of three dichloro and five diiodo complexes were determined, in an attempt to obtain information on the trans influence of the three ligands. The results have shown that the iodo ligand has the greatest trans influence. Chloro and pyridine ligands seem to have similar trans influence, although, the chloro ligand seems to have a slightly larger influence than pyridine derivatives. One structure, trans-Pt(2-pic)2I2, has shown a syn conformation of the two 2-picoline ligands.
Application of microwave-assisted heating to the synthesis of Pt(II) complexes
Gabano, Elisabetta,Gama, Sofia,Mendes, Filipa,Fregonese, Federico,Paulo, António,Ravera, Mauro
, p. 16 - 19 (2015/09/01)
The microwave-assisted synthesis of Pt(II) complexes containing several pyridines (i.e., pyridine L1, 2-picoline L2, 3-picoline L3, 4-picoline L4, 2,2′-bipyridine L5) is reported. For L1-L5, the reaction was successful in about 50% yield with all the ligands except L2. The same method applied to 4,4′-bis(2-morpholinoethoxy)-2,2′-bipyridine (L6, a ligand showing interesting antiproliferative properties because of a high DNA affinity), was unsatisfactory. The corresponding complex cis-[PtCl2(L6)] was obtained only heating at reflux a mixture of [PtCl2(1,5-cyclooctadiene)] and L6 in acetonitrile for 24 h. Antiproliferative activity of [PtCl2(L6)] on four cancer cell lines (ovarian A2780 and its cisplatin-resistant variant A2780cisR, prostate PC3 and breast cancer MDA-MB-231) was compared with that of its ligand and the model complex [PtCl2(L5)]. These studies showed that [PtCl2(L6)] has just marginal activity towards the tested cells if compared with cisplatin.
Synthesis, characterization, and reactivity of trans-[PtCl(R′R″SO)(A)2]NO3 (R′R″SO = ME2SO, MeBzSO, MePhSO; A = NH3, py, pic). Crystal structure of trans-[PtCl(Me2SO)(py)2]+
Fontes,Oskarsson,Loevqvist,Farrell
, p. 1745 - 1750 (2008/10/08)
Trans complexes such as trans-[PtCl2(NH3)2] have historically been considered therapeutically inactive. The use of planar ligands such as pyridine greatly enhances the cytotoxicity of the trans geometry. The complexes trans-[PtCl(R′R″SO)(A)2]NO3 (R′R″SO = substituted sulfoxides such as dimethyl (Me2SO), methyl benzyl (MeBzSO), and methyl phenyl sulfoxide (MePhSO) and A = NH3, pyridine (py) and 4-methylpyridine or picoline (pic)) were prepared for comparison of the chemical reactivity between ammine and pyridine ligands. The X-ray crystal structure determination for trans-[PtCl(Me2SO)(py)2]NO3 confirmed the geometry with S-bound Me2SO. The crystals are orthorhombic, space group P212121, with cell dimensions a = 7.888(2) A, b = 14.740(3) A, c = 15.626(5) A, and Z = 4. The geometry around the platinum atom is square planar with l(Pt-Cl) = 2.304(4) A, l(Pt-S) = 2.218(5) A and l(Pt-N) = 2.03(1) and 2.02(1) A. Bond angles are normal with Cl-Pt-S = 177.9(2)°, Cl-Pt-N1 = 88.0(4)°, Cl-Pt-N2 = 89.3(5)°, S-Pt-N1 = 93.8(4)°, S-Pt-N2 = 88.9(4)°, and N1-Pt-N2 = 177.2(6)°. The intensity data were collected with Mo Kα radiation with a λ = 0.710 69 A. Refinement was by full-matrix least-squares methods to a final R value of 3.80%. Unlike trans-[PtCl2(NH3)2], trans-[PtCl2(A)2] (A = py or pic) complexes do not react with Me2SO. The solvolytic products of cis-[PtCl2(A)2] (A = py or pic) were characterized. Studies of displacement of the sulfoxide by chloride were performed using HPLC. The sulfoxide was displaced faster for the pyridine complex relative to the ammine complex. Chemical studies comparing the reactivity of trans-[PtCl(R′R″SO)(amine)2]NO3 with a model nucleotide, guanosine 5′-monophosphate (GMP), showed that the reaction gave two principal products: the species [Pt(R′R″SO)(amine)2(N7-GMP)], which reacts with a second equivalent of GMP, forming [Pt(amine)2(N7- GMP)2]. The reaction pathways were different, however, for the pyridine complexes in comparison to the NH3 species, with sulfoxide displacement again being significantly faster for the pyridine case.
