152277-66-2Relevant academic research and scientific papers
Multinuclear magnetic resonance spectroscopy and crystal structures of iodo-bridged dinuclear Pt(II) complexes with amines
Rochon, Fernande D.,Buculei, Viorel
, p. 3919 - 3926 (2005)
Complexes of the types cis-Pt(amine)2I2 were transformed into the iodo-bridged dimers, which were characterized mainly by multinuclear (195Pt, 1H and 13C) magnetic resonance spectroscopy. For bulby amines, the dinuclear species were synthesized directly from K2[PtI4]. Compounds with several primary aliphatic and cyclic amines and two secondary amines were studied. In 195Pt NMR, two signals were observed between -3899 and -4080 ppm in acetone. These species were assigned to the cis and trans dinuclear compounds I(amine)Pt(μ-I)2PtI(amine). We suggest that the most shielded compound is the trans isomer. The difference between the two isomers is 12-13 ppm for the primary amine system and 26-27 ppm for the two secondary amines. There seems to be a slight dependence of the proton affinity in the gas phase of the amine (linear amines) with the δ(Pt) chemical shifts of the dinuclear Pt(II) compounds. The 2J(195Pt-1HN) coupling constants are slightly larger for the trans isomers (average 67 Hz, vs. 56 Hz). The 3J(195Pt-1H) coupling constants were detected only for the dimethylamine compounds, 46 Hz (trans) and 44 Hz (cis). In 13C NMR, the values of 2J(195Pt- 13C) and 3J(195Pt-13C) were also found to be very slightly larger for the trans complexes (average 19 and 25 Hz vs. 15 and 18 Hz). The structures were confirmed by X-ray diffraction studies of the n-butylamine and diethylamine compounds. The two crystals were those of the trans dinuclear complexes.
Synthesis and NMR characterization of the novel mixed-ligands Pt(II) complexes Pt(amine)(pyrimidine)X2 and trans,trans-X2(amine)Pt(μ-pyrimidine)Pt(amine)X 2 (X = I and Cl)
Rochon, Fernande D.,Titouna, Hyem
, p. 1679 - 1693 (2010)
Mixed-ligand complexes of the type Pt(amine)(pm)I2, (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 I(amine)Pt(μ-I)2Pt(amine)I with pyrimidine (1:2 proportion) in water, while the trans isomers were synthesized from the isomerization of the cis complexes in acetone. The cis isomers could not be isolated with several amines, especially the more bulky ones. In 1H NMR, the pyrimidine protons of the cis compounds were found at lower fields than those of the trans analogs and the J(195Pt-1H) coupling constants are slightly larger in the cis geometry. For n-butylamine, the reaction produced also I2(n-butylamine)Pt(μ-pm)Pt(n-butylamine)I2. No such dimer could be isolated with the other amines. The compounds Pt(amine)(pm)Cl2 were also prepared (amine = methylamine and t-butylamine) from the ionic complex K[Pt(amine)Cl3] using an excess of pyrimidine. The IR and NMR characterization showed that the methylamine compound was a cis-trans mixture, while only the trans isomer was isolated with t-butylamine. When the same reaction was performed using a Pt:pm ratio of 2:1, Cl2(amine)Pt(μ-pm)Pt(amine)Cl2 was isolated. The pyrimidine-bridged dimers were identified by IR and multinuclear magnetic resonance spectroscopies as the trans-trans isomers. The trans monomers and dimers showed only one ν(Pt-Cl) band. The 195Pt NMR signals of the dimers were found close to those of the monomer trans-Pt(amine)(pm)Cl2.
Crystal and Molecular Structures of Asymmetric cis- and trans-Platinum(II/IV) Compounds and Their Reactions with DNA Fragments
Talman, Eduard G.,Brüning, Wolfgang,Reedijk, Jan,Spek, Anthony L.,Veldman, Nora
, p. 854 - 861 (2008/10/09)
The asymmetrically substituted platinum(II) complexes cis-Pt(NH3)(c-C5H11NH2)Cl 2 and trans-Pt(NH3)(c-C6H11-NH2)Cl 2 have been synthesized and their crystal structures have been determined. Crystals of cis-Pt(NH3)(c-C6H11NH2)Cl 2 (1) are orthorhombic, space group Pbca (no. 61) with a = 10.1994(12), b = 10.494(2), c = 18.826(2) ?, Z = 8. The structure refinement converged to R1 = 0.0518 and wR2 = 0.1143. Crystals of trans-Pt(NH3)(c-C6H11NH2)Cl 2 (2) are monoclinic, space group P21/c (no. 14) with a = 12.141(3), b = 6.0965(9), c = 19.864(3) ?, β= 118.71(2)°, Z = 4. The structure refinement converged to R1 = 0.0711 and wR2 = 0.1846. In addition, the Pt(IV) analogues with axial hydroxide ligands have been synthesized. Also the corresponding bis(carboxylato)-platinum(IV) compound of formula trans,cis,cis-Pt(NH3)(c-C6H11NH 2)Cl2(OOCCH3)2 has been obtained by conversion of the hydroxide with acetic anhydride. Reactions of these platinum complexes with 9-methylhy-poxanthine and guanosine-5′-monophosphate (5′-GMP) have been studied in significant detail. The course of the reactions was followed by NMR spectroscopy, and 1H and 195Pt techniques were used to identify the formation of the products. It was found that the Pt(II) compounds easily react with the bases at the N7 position, whereas the Pt(IV) compounds react very slowly (for trans,cis,cis-Pt(NH3)(c-C6H11NH 2)Cl2(OOCCH3)2) or not at all (for trans,trans,trans-Pt(NH3)(c-C6H11NH 2)Cl2(OH)2). Only in the presence of glutathione does a reaction of the latter with 5′-GMP takes place. In this case a major product was found to be the reduced trans-Pt(II) complex with one molecule of 5′-GMP and one molecule of S-bonded glutathione.
