64827-25-4

Upstream product

• 27476-72-8 {PtPh₂-bis(diethyl sulphide)} 
• 64827-26-5 cis-{Pt2(Ph)4-bis(μ-diethyl sulphide)} 
• 80510-03-8 Tris(pyrazolyl)methane 

Relevant academic research and scientific papers

Factors affecting reaction pathways in nucleophilic substitution reactions on platinum(II) complexes: A comparative kinetic and theoretical study

Kinetic studies in CH2Cl2 of the displacement of the thioethers from cis-[PtPh2(Et2S)2] with pyridine or substituted pyridines to yield cis-[PtPh2(py)2] show, in agreement with previous findings, that the rate-determining step is dissociation of a molecule of thioether and the formation of a transient 3-coordinate [Pt(Ph)2(Et2S)] intermediate. At 298.16 K, the rate constant for dissociation k1 = (2.12 ± 0.1) × 10-3 s-1, ΔH? = 99.9 ± 1 kJ mol-1 and ΔS? = +39 ± 4 J mol-1 K-1. In contrast, the complex cis-[PtPh2(CO)(Et2S)], in the same reactions and under the same experimental conditions, undergoes substitution of Et2S only through a bimolecular pathway, showing a considerable discrimination among various nucleophiles. In the reaction with pyridine, the second-order rate constant k2 = 30.0 ± 0.1 M-1 s-1, ΔH? = 34 ± 1 kJ mol-1, ΔS? = -174 ± 4 J mol-1 K-1. Extended Huckel theory (EHT) and molecular electrostatic potential (MEP) calculations were performed on molecules of the type cis-[PtCl2S2], cis-[PtMe2S2], and cis-[PtMe2(CO)S] (S = Me2S or Me2SO), searching for a correlation between electronic properties and pathways followed for substitution. The sharp changeover of mechanism (dissociative vs. associative) observed on going from the diaryl disulfide to the diaryl carbonyl sulfide platinum(II) complex, is accounted for by the presence on the latter of a LUMO perpendicular to the plane, suitable to the nucleophilic attack, and by a large positive electronic potential. Dissociation is a combined result of ground-state destabilization and of a concurrent increase of electron density at the metal, preventing the approach of nucleophiles.

Cyclometallation of polydentate ligands containing pyrazole groups, including the synthesis of platinum(IV) complexes with tripodal - ligand systems

Dimethylplatinum(II) complexes, PtR2(L), have been made by reaction of 2 with a range of polydentate nitrogen donor ligands containing one or more pyrazol-1-yl (pz) donor groups, including the new ligand bis(pyrazol-1-yl)(thien-2-yl)methane.The complexes give cis-PtMe2(py)2 when dissolved in pyridine at ambient temperature, except for PtMe2(L) (L = (pz)2CH2, (pz)2C(H)Ph, (pz)3CH, or (pz)2(mim)CH (mim = N-methylimidazol-2-yl)), which undergo cyclometallation at a C(5) position of one pyrazol-1-yl ring.The cyclometallated ligands have been examined as 'isoelectronic' analogues of nitrogen donor poly(pyrazol-1-yl)alkane and poly(pyrazol-1-yl)borate ligands.A carbon monoxide derivative, PtMe(CO) (1d) and a series of phosphine complexes have been prepared.The complex PtMe(py) (1a) and polymeric >n (2) undergo oxidative addition reactions with organohalides to give the platinum(IV) complexes (py)>X (7a-d) and fac-PtXMe(R) (8a-b), respectively.The new reagent 1-bromo-2-(pyrazol-1-yl)ethane forms (pzCH2CH2-N,C)>Br (10), containing both - and - ligands.Reaction of MeI or PhCH2Br with PtMe2> gives fac-PtXMe(R) (8a,b) directly, and PtMe2 undergoes a similar cyclometallation/oxidative addition in iodomethane to form fac-PtIMe2 (13).

Mechanisms of thermal rearrangement of diarylbis(pyridine)platinum(II) complexes: Reductive carbon-carbon elimination versus hydrogen transfer

Thermolytic behavior in solution of a series of complexes cis-(py)2Pt(4-C6H4R)2 (R = H, CMe3, CF3; py = pyridine) has been examined. When R = CMe3, thermolytic rearrangement generates biaryl via unimolecular reductive elimination without prerequisite ligand dissociation. Arene elimination is an important, temperature-dependent, competitive reaction, which is suppressed by deuteriation of either aryl or pyridine ligands. Comparison with photolytic rearrangement of Hg(4-C6H4CMe3)2 indicates that Pt-C homolysis is not a significant contributor. A mechanism is indicated in which successive, reversible H transfers from pyridine and aryl ligands may occur, the latter resulting in a rare example of aryl group isomerization prior to elimination. For R = H, similar mechanistic competition is observed, but when R = CF3, concerted mononuclear reductive elimination is the only significant pathway. Its activation parameters suggest conformational restriction in the transition state. Metallic Hg alters the rearrangement pattern but not by scavenging heterogeneous byproducts.