Tuning N-Heterocyclic Carbenes in T-Shaped PtII Complexes for Intermolecular CH Bond Activation of Arenes

Fluorination Reactions at a Platinum Carbene Complex: Reaction Routes to SF3 , S(=O)F and Fluorido Complexes

The electron-rich Pt complex [Pt(IMes)2 ] (IMes: [1,3-bis(2,4,6-trimethylphenyl)-2-imidazolinylidine]) can be used as precursor for the syntheses of a variety of fluorido ligand containing compounds. The sulfur fluoride SF4 undergoes a rapid oxidative addition at Pt0 to yield trans-[Pt(F)(SF3 )(IMes)2 ]. A photolytic reaction of SF6 at [Pt(IMes)2 ] in the presence of IMes gave the fluorido complexes trans-[Pt(F)2 (IMes)2 ] and trans-[Pt(F)(SF3 )(IMes)2 ] along with trans-[Pt(F)(SOF)(IMes)2 ] and trans-[Pt(F)(IMes')(IMes)] (IMes': cyclometalated IMes ligand), the latter being products produced by reaction with adventitious water. trans-[Pt(F)(SOF)(IMes)2 ] and trans-[Pt(F)2 (IMes)2 ] were synthesized independently by treatment of [Pt(IMes)2 ] with SOF2 or XeF2 . A reaction of [Pt(IMes)2 ] with a HF source gave trans-[Pt(H)(F)(IMes)2 ], and an intermediate bifluorido complex trans-[Pt(H)(FHF)(IMes)2 ] was identified. Compound trans-[Pt(H)(F)(IMes)2 ] converts in the presence of CsF into trans-[Pt(F)(IMes')(IMes)].

Taming the Cationic Beast: Novel Developments in the Synthesis and Application of Weakly Coordinating Anions

This Review gives a comprehensive overview of the most topical weakly coordinating anions (WCAs) and contains information on WCA design, stability, and applications. As an update to the 2004 review, developments in common classes of WCA are included. Methods for the incorporation of WCAs into a given system are discussed and advice given on how to best choose a method for the introduction of a particular WCA. A series of starting materials for a large number of WCA precursors and references are tabulated as a useful resource when looking for procedures to prepare WCAs. Furthermore, a collection of scales that allow the performance of a WCA, or its underlying Lewis acid, to be judged is collated with some advice on how to use them. The examples chosen to illustrate WCA developments are taken from a broad selection of topics where WCAs play a role. In addition a section focusing on transition metal and catalysis applications as well as supporting electrolytes is also included.

True and masked three-coordinate T-shaped platinum(II) intermediates

Although four-coordinate square-planar geometries, with a formally 16-electron counting, are absolutely dominant in isolated Pt(II) complexes, three-coordinate, 14-electron Pt(II) complexes are believed to be key intermediates in a number of platinum-mediated organometallic transformations. Although very few authenticated three-coordinate Pt(II) complexes have been characterized, a much larger number of complexes can be described as operationally three-coordinate in a kinetic sense. In these compounds, which we have called masked T-shaped complexes, the fourth position is occupied by a very weak ligand (agostic bond, solvent molecule or counteranion), which can be easily displaced. This review summarizes the structural features of the true and masked T-shaped Pt(II) complexes reported so far and describes synthetic strategies employed for their formation. Moreover, recent experimental and theoretical reports are analyzed, which suggest the involvement of such intermediates in reaction mechanisms, particularly C-H bond-activation processes.