33915-19-4

Upstream product

• 10199-34-5 bis(triphenylphosphine)platinum(II) dichloride 
• 7783-99-5 silver(I) nitrite 
• 10199-34-5 cis-dichlorobis(triphenylphosphine)platinum(II) 

Relevant academic research and scientific papers

Cooperation between cis and trans influences in cis-Pt II(PPh3)2 complexes: Structural, spectroscopic, and computational studies

The relevance of cis and trans influences of some anionic ligands X and Y in cis-[PtX2(PPh3)2] and cis-[PtXY(PPh 3)2] complexes have been studied by the X-ray crystal structures of several derivatives (X2 = (AcO)2 (3), (NO3)2 (5), Br2 (7), I2 (11); and XY = Cl(AcO) (2), Cl(NO3) (4), and Cl(NO2) (13)), density functional theory (DFT) calculations, and one bond Pt-P coupling constants, JPtp. The latter have allowed an evaluation of the relative magnitude of both influences. It is concluded that such influences act in a cooperative way and that the cis influence is not irrelevant when rationalizing the 1 JPtp values, as well as the experimental Pt-P bond distances. On the contrary, in the optimized geometries, evaluated through B3LYP/def2-SVP calculations, the cis influence was not observed, except for compounds CIPh (21), Ph2 (22), and, to a lesser extent, Cl(NO2) (13) and (NO2) 2(14). A natural bond order analysis on the optimized structures, however, has shown how the cis influence can be related to the s-character of the Pt hybrid orbital involved in the Pt-P bonds and the net atomic charge on Pt. We have also found that in the X-ray structures of cis-[PtX 2(PPh3)2] complexes the two Pt-X and the two Pt-P bond lengths are different each other and are related to the conformation of the phosphine groups, rather than to the crystal packing, since this feature is observed also in the optimized geometries.

Observations regarding the mechanisms of O atom transfer from metal nitro ligands to oxidizable substrates

New experimental evidence is presented related to the mechanism of O atom transfer from metal nitro complexes to alkenes and carbon monoxide. Oxidation of alkenes by the nitro complex (py)CoTPPNO2 in the presence of Pd(CH3CN)2Cl2 as a cocatalyst is found to give product distributions that do not exactly match those expected for the simple intermolecular bimetallic O atom transfer originally proposed. Pyridine, nitro, and nitrosyl ligand exchange between the cobalt and palladium are found to be facile. In one plausible revised mechanism, the bimetallic alkene oxidation could therefore proceed via nitro group transfer to palladium, oxidation via the same metallacycles as for the monometallic Pd(CH3CN)2ClNO2 catalyst, and transfer of the resulting nitrosyl ligand back to cobalt. Several other complex mechanisms cannot be ruled out. Other systems were also investigated, but no evidence could be found for a bimetallic open-chain intermediate formed by intermolecular addition of a metal nitro complex to a coordinated alkene. A literature claim for intermolecular O atom transfer from metal nitro groups to carbon monoxide based on isotopic double-labeling experiments is incomplete due to the absence of suitable control experiments. Attempts to carry out the requisite controls were hampered by experimental limitations, but the results obtained again show that there is no compelling evidence for intermolecular O atom transfer from a metal nitro group.