185226-17-9

Upstream product

• 185226-17-9 trans(C,N)-chloromethyl(dimethyl sulfoxide)(2-phenylpyridine)platinum(II) 
• 1008-89-5 2-phenylpyridine 
• 185226-19-1 trans-chloromethylbis(dimethylsulfoxide)platinum(II) 

Downstream Products

• 185226-17-9 cis(C,N)-chloromethyl(dimethyl sulfoxide)(2-phenylpyridine)platinum(II) 

Relevant academic research and scientific papers

trans-Chloromethylbis(dimethyl sulfoxide)platinum(II): X-ray Structure, Mechanism of Isomerization, and Its Use as a Precursor to Organoamine Complexes of Variable Geometrical Configurations

An unusual 2:1 aggregate between the complex trans-[PtCl(CH3)(DMSO)2] (1; DMSO = dimethyl sulfoxide) and the organotin compound bis(μ 3-oxo)bis(μ-chloro)bis(μ-dimethyltin(IV)) bis(chlorodimethyltin(IV)) [Cl(CH3)2-SnOSn(CH3)2Cl]2 has been isolated and characterized by X-ray analysis. The crystals belong to the triclinic space group P1? with lattice constants a = 9.373(2) A?, b = 9.576(1) A?, c = 14.087(3) A?, α = 70.29(1)°, β = 72.50(1)°, γ = 72.21(2)°, and Z = 2. Least-squares refinement of the structure led to an R factor of 2.37%. 1H, 13C, and 195Pt NMR measurements revealed that in chloroform solution complex 1 gives a mixture of four different species, which have been unambiguously identified as the starting complex 1 in equilibrium with cis-[PtCl(CH3)-(DMSO)2] and the two corresponding isomeric aqua-species cis and trans-[PtCl(CH3)(DMSO)(OH2)]. The 195Pt NMR magnetization transfer technique allowed determination of the rate of interconversion among the various complexes, showing that the direct trans-cis isomerism between the [PtCl(CH3)(DMSO)2] species is negligible and that the geometrical interconversion occurs through a water-catalyzed pathway. The exchange between free and coordinated DMSO in cis- and trans-[PtCl(CH3)(DMSO)2] has been measured by 1H NMR magnetization transfer experiments. The molecule of DMSO in the position trans to a methyl group was found to be 10-fold more labile than that trans to another sulfur bonded dimethyl sulfoxide. The reactivity of complex 1 in chloroform with a series of monodentate nitrogen ligands having widely different electronic and steric properties has been investigated by 1H NMR spectroscopy. The utility of this system as precursor for the synthesis of cis- and trans-[PtCl(CH3)(DMSO)(am)] is discussed together with the evidence for the factors promoting the prevalence of a geometrical configuration.

Geometrical configuration of monomethyl-platinum(II) complexes driven by the size of entering nitrogen ligands

The reaction of the monoalkyl complex trans-[Pt(DMSO)2Cl(CH3)] with a large variety of heterocyclic nitrogen bases L, in chloroform solution, leads to the formation of uncharged complexes of the type [Pt(DMSO)(L)Cl(CH3)], containing four different groups coordinated to the metal center. Only two out of the three different possible isomers were detected in solution. These two trans(C,N) and cis(C,N) species can be unambiguously identified through 1H NMR spectroscopy. For the trans(C,N) isomers, average values of 2JPtH=75±4 Hz and 3JPtH=36±4 Hz have been observed for the coordinated methyl and DMSO ligands, respectively. In the case of the cis(C,N) isomers, these values increase to 2JPtH=83±2 Hz, and decrease to 3JPtH=26±3 Hz due to the mutual exchange of ligands in trans position to CH3 and DMSO. In the case of bulky asymmetric ligands, such as quinoline, 2-quinolinecarboxaldehyde, 2-methylquinoline, 5-aminoquinoline, 2-phenylpyridine and 2-chloropyridine, slow rotation of the hindered group around the Pt-N bond makes the coordinated DMSO ligand prochiral. NMR experiments have shown that the first reaction product is the trans(C,N) isomer as a consequence of the very fast removal of one DMSO ligand by the nitrogen bases from the starting complex trans-[Pt(DMSO)2Cl(CH3)]. This trans kinetic product undergoes a geometrical conversion into the more stable cis(C,N) isomer through the intermediacy of fast exchanging aqua-species. The rate of isomerization and the relative stability of the two isomers depends essentially on the rate of aquation and on the steric congestion imposed by the new L ligand on the metal.