A re-investigation of the electrochemistry of isomeric [PtCl2(PR3)2] complexes by cyclic voltammetry

Synthesis and Electrochemistry of Heterobimetallic Ruthenium/Platinum and Molybdenum/Platinum Complexes

“…The Pt(II/IV) oxidations are observed at 1.65 and 1.82 V for the trans and cis isomers, respectively. These assignments correspond with reported trends for trans and cis forms of four-coordinate Pt oxidation potentials. , Substitution of CH 3 CN for Cl - at the platinum center has little effect on the oxidation potentials of the molybdenum center, as can be seen when the Mo(II/III) potentials of MoCp(CO) 2 (μ-PPh 2 )(μ-H)Pt(PPh 3 )Cl and 8 are compared (Table ). However, a positive shift in the Pt potentials is observed, generally consistent with the notion of a cationic compound being more difficult to oxidize.…”

Electrochemical investigations of platinum phenylethynyl complexes

“…Phenylacetylene, which is the phenylethynyl ligand alone, does not have significant oxidation peaks in this range. Tributylphosphine is not likely to undergo oxidation, because the oxidations of other similar platinum complexes in this same region are not attributed to phosphine oxidation [20,21]. Also, while the lone pair on phosphorus on free tributylphosphine can be oxidized in the potential range under study [23], in the complexed form the lone pair is in use in a bond and is not easily oxidized.…”

“…The electrochemistry of other platinum ethynyl complexes has shown that irreversible removal of two electrons from Pt(II) to form Pt(IV) is very common, and in fact Pt(III) complexes form only under unusual circumstances [14,15]. This is true not only of Pt ethynyls but of other Pt complexes as well [16][17][18][19][20][21], although Pt(III) intermediates sometimes form briefly and then disproportionate into Pt(II) and Pt(IV) species [22]. An electron loss from the Pt(II) center would come from a nonbonding metalcentered orbital, rather than the HOMO of the molecule.…”

“…We also report on preliminary experiments that attempt to characterize the products of chemical reactions that follow the irreversible oxidation of PE1. This has not been done for platinum ethynyls, although it has for other Pt(II) complexes [20,21].…”

Phosphite Bearing [(μ-ADT)RFe2(CO)6] (ADT = Azadithiolate) Moieties: A Tool for the Building of Multimetallic [FeFe]-Hydrogenase Mimics

“…Reduction of the Pt(II) nucleus should occur at more negative potentials according to the literature data. 74,75 Alternatively, Pd(II) phosphite complexes experience two sequential reduction processes at −0.76 and −1.20 V. 76 Complexes 5 are stable in the presence of increasing amounts of acetic acid, as observed by 1 H NMR spectroscopy analysis (see Figures S24 and S25). Therefore, the wave around −1.40 V should be caused by an acid-promoted by-reaction along the electrochemical process.…”