72151-35-0Relevant academic research and scientific papers
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.
Synthesis and Characterization of Pt(II) Complexes with Pyridyl Ligands: Elongated Octahedral Ion Pairs and Other Factors Influencing 1H NMR Spectra
Lewis, Nerissa A.,Pakhomova, Svetlana,Marzilli, Patricia A.,Marzilli, Luigi G.
supporting information, p. 9781 - 9793 (2017/08/26)
Our goal is to develop convenient methods for obtaining trans-[PtII(4-Xpy)2Cl2] complexes applicable to 4-substituted pyridines (4-Xpy) with limited volatility and water solubility, properties typical of 4-Xpy, with X being a moiety targeting drug delivery. Treatment of cis-[PtII(DMSO)2Cl2] (DMSO = dimethyl sulfoxide) with 4-Xpy in acetonitrile allowed isolation of a new series of simple trans-[PtII(4-Xpy)2Cl2] complexes. A side product with very downfield H2/6 signals led to our synthesis of a series of new [PtII(4-Xpy)4]Cl2 salts. For both series in CDCl3, the size of the H2/6 δ[coordinated minus free 4-Xpy H2/6 shift] decreased as 4-Xpy donor ability increased from 4-CNpy to 4-Me2Npy. This finding can be attributed to the greater synergistic reduction in the inductive effect of the Pt(II) center with increased 4-Xpy donor ability. The high solubility of [PtII(4-Xpy)4]Cl2 salts in CDCl3 (a solvent with low polarity) and the very downfield shift of the [PtII(4-Xpy)4]Cl2 H2/6 signals for the solutions provide evidence for the presence of strong {[PtII(4-Xpy)4]2+,2Cl-} ion pairs that are stabilized by multiple CH···Cl contacts. This conclusion gains considerable support from [PtII(4-Xpy)4]Cl2 crystal structures revealing that a chloride anion occupies a pseudoaxial position with nonbonding (py)C-H···Cl contacts (2.4-3.0 ?). Evidence for (py)C-H···Y contacts was obtained in NMR studies of [PtII(4-Xpy)4]Y2 salts with Y counterions less capable of forming H-bonds than chloride ion. Our synthetic approaches and spectroscopic analysis are clearly applicable to other nonvolatile 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.
Thermal solid state synthesis of coordination complexes from hydrogen bonded precursors
Adams, Christopher J.,Crawford, Paul C.,Orpen, A. Guy,Podesta, Thomas J.,Salt, Benjamin
, p. 2457 - 2458 (2007/10/03)
Thermal dehydrochlorination of crystalline 4-picolinium salts of [PtCl 4]2- and [PdCl4]2 leads to formation of trans-[MCl2(4-picoline)2] (M = Pt, Pd). The Royal Society of Chemistry 2005.
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.
Platinum(II) complexes of substituted pyridine and pyrazole derivatives
Mostafa Hossain,Ogura
, p. 373 - 378 (2007/10/03)
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.
Acid-Base Equilibria of Co-ordinated Ligands. Part 1. The Effect of Basicity of Co-ordinated Nitrogen Donors upon the Acidity of Chelating 8-Aminoquinoline in some Dicationic Platinum(II) Complexes
Annibale, Giuliano,Cattalini, Lucio,Guidi, Francesca
, p. 731 - 734 (2007/10/02)
Cationic complexes of the type 2 and 2 (8NH2-quin = 8-aminoquinoline), where L and L-L are mono- and bi-dentate nitrogen donors respectively, have been prepared.In aqueous solution, they undergo reversible
The cis- and trans-Effects of Cyanide in Substitution at Platinum(II)
Cattalini, Lucio,Guidi, Francesca,Tobe, Martin L.
, p. 233 - 236 (2007/10/02)
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
Organoamidometallics. II. Decarboxylation Syntheses and Structures of platinum(II) Complexes
Buxton, David P.,Deacon, Glen B.,Gatehouse, Bryan M,Grayson, Ian L.,Black, David St. C.
, p. 943 - 956 (2007/10/02)
The complexes (L = py, X = Cl or Br; L = 2-methylpyridine or 4-methylpyridine, X = Cl) have been prepared by decarboxylation reactions between PtX2(dmen) (dmen = N,N-dimethylethane-1,2-diamine) and thallous pentafluorobenzoate in the appropriate hot pyridine.Other organoamidoplatinum(II) complexes, (R = p-HC6F4, X = I; R = C6F5, X = Cl, Br or I; R = p-MeC6F4, X = Cl; R = p-ClC6F4 or p-BrC6F4, X = I) and (R = p-HC6F4; dmpy = 2,5-dimethylpyridine), have been prepared by analogous decarboxylations between PtX2(dmen), thallous 2,3,5,6-tetrafluorobenzoate, and the corresponding polyfluorobenzene, RF.The mixed halogen complex has been prepared similarly and the crystal structure determined.This shows square-planar stereochemistry with the halogen and pyridine trans to NC6F5 and NMe2 respectively.Comparison of spectroscopic data suggests the other complexes have similar stereochemistry.
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)
Cattalini, Lucio,Marangoni, Giampaolo,Michelon, Gianni,Paolucci, Gino,Tobe, Martin L.
, p. 71 - 75 (2008/10/08)
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.
