- Synthesis and NMR characterization of the novel mixed-ligand Pt(II) complexes cis- and trans-Pt(Ypy)(pyrimidine)Cl2 and trans,trans-Cl2(Ypy)Pt(μ-pyrimidine)Pt(Ypy)Cl2 (Ypy = pyridine derivative)
-
Mixed-ligand complexes of the type cis- and trans-Pt(Ypy)(pm)Cl2 where Ypy = pyridine derivative and pm = pyrimidine were synthesized and characterized by IR spectroscopy and by multinuclear (195Pt, 1H and 13C) magnetic resonance spectroscopy. The cis compounds were prepared from the reaction of K[Pt(Ypy)Cl3] with pyrimidine (1:1 proportion) in water, while most of the trans isomers were synthesized from the isomerization of the cis compounds. The cis isomers could not be isolated with the Ypy ligands containing two -CH3 groups in ortho positions. When the aqueous reaction of K[Pt(Ypy)Cl3] with pyrimidine was performed in a Pt:pm ratio = 2:1, the pyrimidine-bridged dinuclear species were formed. Only the most stable trans-trans isomers could be isolated pure. In IR spectroscopy, the cis monomers showed two ν(Pt-Cl) bands, while the trans monomers and dimers showed only one ν(Pt-Cl) band. The 195Pt NMR signals of the cis monomers were found at slightly higher fields than those of the corresponding trans isomers. The δ(195Pt) of the dimers were found close to those of the trans monomers. The NMR results were interpreted in relation to the solvent effect, which seems important in these complexes. The coupling constants J(195Pt-1H) and J(195Pt-13C) are larger in the cis geometry. The crystal structures of the compounds cis-Pt(2,4-lut)(pm)Cl2, trans-Pt(2,6-lut)(pm)Cl2 and trans,trans-Cl2(2,6-lut)Pt(μ-pm)Pt(Ypy)Cl2 were studied by X-ray diffraction methods and the results have confirmed the configurations suggested by IR and NMR spectroscopies.
- Rochon, Fernande D.,Fakhfakh, Majd
-
p. 1455 - 1466
(2009/08/08)
-
- Platinum(II) complexes of substituted pyridine and pyrazole derivatives
-
A series of new platinum(II) halo complexes of substituted pyridines and pyrazoles: [trans-PtCl2(C7H7N)2], [trans-PtCl2(C3H4N2)2], [trans-PtCl2(C6H7N)2] and [trans-PtCl2(C4H6N2)2] has been synthesized, and the complexes have been characterised on the basis of their IR, 1H NMR, UV/vis and elemental analysis data. Trans-dichloroplatinum(II) complexes of nitrogen cyclic compounds have been prepared through the reaction of K2[PtCl4] with the corresponding ligands in water or a mixture of water and an organic solvent. The coordination reaction of 3- or 4-substituted pyridine is complete within 10 h and the yields are more than 60%, but that of 2-substituted pyridine requires a longer time (15 h) and the yields are low (44%). Platinum complexes of pyridine with a vinyl group at the ortho position could not be obtained, but those with a methyl or a vinyl group at the para position have been obtained. Each complex has a trans square-planar structure, the platinum being coordinated by two halogen and two nitrogen atoms and lying at a centre of symmetry.
- Mostafa Hossain,Ogura
-
p. 373 - 378
(2007/10/03)
-
- Hindered rotation of ligands in cis- complexes
-
The temperature dependence of the 1H NMR spectra of cis- complexes was studied in DMSO at 18 - 100 deg C (R is 2-methyl and 2,5-dimethylpyridine).The broadening of the signals from the methyl groups or hydrogen atoms in the ortho-positions of
- Bondarenko, V. S.,Korniets, E. D.,Sokolenko, B. A.,Kovrova, N. B.
-
p. 388 - 389
(2007/10/02)
-
- The cis- and trans-Effects of Cyanide in Substitution at Platinum(II)
-
The cis- and trans- isomers (am = dimethylamine, pyridine, 4-cyanopyridine, 4-chloropyridine, 2-methylpyridine, 4-methylpyridine, 2,4-dimethylpyridine, 4-ethylpyridine, morpholine or piperidine), react rapidly with excess CN(1-) in methanol to
- Cattalini, Lucio,Guidi, Francesca,Tobe, Martin L.
-
p. 233 - 236
(2007/10/02)
-
- Nucleophilic displacement of the chelating bis(sulfoxide) from cis-[meso-1,2-bis(phenylsulfinyl)ethane]dichloroplatinum(II) and cis-[rac-1,2-bis(phenylsulfinyl)ethane]dichloroplatinum(II)
-
The kinetics of ring opening, by amines in 1,2-dimethoxyethane, have been measured for two bis(sulfoxide)-platinum(II) isomers. The results make possible a discussion of the differences between the two isomers, in comparison with other platinum(II) complexes, in terms of absolute reactivity, nucleophilic discrimination, and steric retardation effects.
- Cattalini, Lucio,Marangoni, Giampaolo,Michelon, Gianni,Paolucci, Gino,Tobe, Martin L.
-
-