Oxidative addition reaction of diarylplatinum(II) complexes with MeI in ionic liquid media: a kinetic study

Tetranuclear rollover cyclometalated organoplatinum-rhenium compounds; C-I oxidative addition and C-C reductive elimination using a rollover cycloplatinated dimer

The novel tetranuclear Pt(IV)-Re(VII) complex [Pt₂Me₄(OReO₃)₂(PMePh₂)₂(µ-bpy-2H)], 4, is synthesized through the reaction of silver perrhenate with a new rollover cycloplatinated(IV) complex [Pt₂Me₄I₂(PMePh₂)₂(µ-bpy-2H)], 3. In complex 4, while 2,2'-bipyridine (bpy) acts as a linker between two Pt metal centers, oxygen acts as a mono-bridging atom between Pt and Re centers through an unsupported Pt(IV)-O-Re(VII) bridge. The precursor rollover cycloplatinated(IV) complex 3 is prepared by the MeI oxidative addition reaction of the rollover cycloplatinated(II) complex [Pt₂Me₂(PMePh₂)₂(µ-bpy-2H)], 2. Complex 2 shows a metal-to-ligand charge-transfer band in the visible region, which was used to investigate the kinetics and mechanism of its double MeI oxidative addition reaction. Based on the experimental findings, the classical S_N2 mechanism was suggested for both steps and supported by computational studies. All complexes are fully characterized using multinuclear NMR spectroscopy and elemental analysis. Attempts to grow crystals of the rollover cycloplatinated(IV) dimer 3 yielded a new dimer rollover cyclometalated complex [Pt₂I₂(PMePh₂)₂(µ-bpy-2H)], 5, presumably from the C-C reductive elimination of ethane. The identity of complex 5 was confirmed by single crystal X-ray diffraction analysis.

Photophysical Properties and Kinetic Studies of 2-Vinylpyridine-Based Cycloplatinated(II) Complexes Containing Various Phosphine Ligands

A series of cycloplatinated(II) complexes with general formula of [PtMe(Vpy)(PR₃)], Vpy = 2-vinylpyridine and PR₃ = PPh₃ (1a); PPh₂Me (1b); PPhMe₂ (1c), were synthesized and characterized by means of spectroscopic methods. These cycloplatinated(II) complexes were luminescent at room temperature in the yellow–orange region’s structured bands. The PPhMe₂ derivative was the strongest emissive among the complexes, and the complex with PPh₃ was the weakest one. Similar to many luminescent cycloplatinated(II) complexes, the emission was mainly localized on the Vpy cyclometalated ligand as the main chromophoric moiety. The present cycloplatinated(II) complexes were oxidatively reacted with MeI to yield the corresponding cycloplatinated(IV) complexes. The kinetic studies of the reaction point out to an S_N2 mechanism. The complex with PPhMe₂ ligand exhibited the fastest oxidative addition reaction due to the most electron-rich Pt(II) center in its structure, whereas the PPh₃ derivative showed the slowest one. Interestingly, for the PPhMe₂ analog, the trans isomer was stable and could be isolated as both kinetic and thermodynamic product, while the other two underwent trans to cis isomerization.

An in-depth investigation on the C–I bond activation by rollover cycloplatinated(ii) complexes bearing monodentate phosphane ligands: kinetic and kinetic isotope effect

The oxidative addition reaction of MeI reagent to some cycloplatinated(ii) complexes was performed and kinetically investigated.

Reactivity of a new aryl cycloplatinated(ii) complex containing rollover 2,2′-bipyridine N-oxide toward a series of diphosphine ligands

A new rollover cycloplatinated(ii) complex was prepared. The reactivity of this complex was investigated towards a wide range of diphosphine ligands.

Oxidation of a rollover cycloplatinated(ii) dimer by MeI: a kinetic study

The known rollover cycloplatinated(ii) complex [Pt₂Me₂(PPh₃)₂(μ-bpy-2H)], 1, in which bpy-2H acts as a bridging rollover ligand, reacts with MeI to give a new binuclear rollover cycloplatinated(iv) complex [Pt₂Me₄I₂(PPh₃)₂(μ-bpy-2H)], 2.