Photochemical Reactions of Fluorinated Pyridines at Half-Sandwich Rhodium Complexes: Competing Pathways of Reaction

C–F bond activation of perfluorinated arenes using NHC-stabilized cobalt half-sandwich complexes

A study on the reactivity of cobalt half-sandwich complexes [Cp(*)Co(NHC)(olefin)] with perfluoroarenes demonstrates that C–F activation occurs along a one-electron oxidative addition pathway.

Strong metal-borane interactions in low-valent cyclopentadienyl rhodium complexes

The first examples of half-sandwich Rh(i) complexes stabilized by borane coordination have been prepared and structurally characterized. As substantiated by NMR spectroscopy and single-crystal X-ray diffraction, the phosphine-borane ligand iPr₂P-(o-C₆H₄)-BFxyl₂ 1 [Fxyl = 3,5-(F₃C)₂C₆H₃] engages in tight η³-BCC or η¹-B coordination, depending on the metal environment.

Selective Carbanion-Pyridine Coordination of a Reactive P,N Ligand to RhI

Ligands with reactive carbon sites in the periphery of a metal center have emerged as a powerful approach for metal-ligand bond activation. These reactive carbon sites are commonly generated by deprotonation strategies. Carbon-silicon bond cleavage is a potential alternative to access such constructs. Herein, the monodesilylation of bis-silyl-substituted P,N scaffold PNSi2 in the coordination sphere of [RhI (Cl)(CO)(PNSi2 )] (1) with sodium azide is disclosed. This affords a unique dinucleating anionic κ2 -C,N-κ1 -P ligand with a carbanionic methine carbon atom directly bound to rhodium as part of a four-membered Rh-N-C-C rhodacycle. This dimer undergoes meta-pyridine C-H activation facilitated by weak bases, which leads to a desymmetrization of the system and provides a σ,π-bridging 3-pyridyl fragment bound to RhI . The facile Si-C cleavage strategy may pave the way to studying the reactivity and functionalization of a variety of κ2 -C,N-coordinated pyridine scaffolds for selective transformations.

Ruthenium(ii)-catalyzed α-fluoroalkenylation of arenes via C–H bond activation and C–F bond cleavage

1,2-Diaryl-substituted monofluoroalkenes with good regio-and stereo-selectivities were achieved through C–H activation by a Ru(ii)-catalyst.

The selective activation of a C–F bond with an auxiliary strong Lewis acid: a method to change the activation preference of C–F and C–H bonds

Selective activations of C–F bond in substituted (2,6-difluorophenyl)phenylimines by Fe(PMe₃)₄ with an auxiliary strong Lewis acid were explored.

Synthesis and structure of rhodium(i) silyl carbonyl complexes: photochemical C-F and C-H bond activation of fluorinated aromatic compounds

The rhodium(i) silyl carbonyl complexes [Rh{Si(OEt)3}(CO)(dippp)] () and [Rh{Si(OEt)3}(CO)(dippe)] () (dippp = 1,3-bis(diisopropylphosphino)propane, dippe = 1,2-bis-(diisopropylphosphino)ethane) were synthesized on treatment of the methyl compounds [Rh(CH3)(CO)(dippp)] () or [Rh(CH3)(CO)(dippe)] () with HSi(OEt)3 at low temperature. The methyl complexes and were prepared starting from the binuclear complexes [{Rh(μ-Cl)(dippp)}2] () and [{Rh(μ-Cl)(dippe)}2] (), respectively. The silyl complexes and as well as the precursors [{Rh(μ-I)(dippp)}2] (), [Rh(X)(CO)(dippp)] (: X = CH3, : X = I) and [Rh(X)(CO)(dippe)] (: X = CH3, : X = Cl) were characterized by NMR and IR spectroscopy and the structures in the solid state were determined by X-ray crystallography. The silyl complex converts into the carbonyl-bridged complex [{Rh(μ-CO)(dippp)}2] () above temperatures of -30 °C by loss of the silyl ligand, whereas is more thermally stable and a reaction to the binuclear complex [{Rh(μ-CO)(dippe)}2] () was observed at 50 °C. The silyl complex reacted under irradiation with hexafluorobenzene and pentafluoropyridine to give the C-F activation products [Rh(C6F5)(CO)(dippe)] () and [Rh(2-C5F4N)(CO)(dippe)] (), respectively. As additional products the silyl dicarbonyl complex [Rh{Si(OEt)3}(CO)2(dippe)] () and the cationic complex [Rh2(μ-H)(μ-CO)2(dippe)2](+)[SiF5](-) () were identified. Compound was synthesized independently by treatment of with gaseous CO. In a similar manner, the dippp analogue [Rh{Si(OEt)3}(CO)2(dippp)] () was also prepared starting from . Photochemical reaction of with pentafluorobenzene and 2,3,5,6-tetrafluoropyridine resulted selectively in C-H bond activation to afford and [Rh(4-C5F4N)(CO)(dippe)] (), respectively.

Oxidative addition of ether O-methyl bonds at a Pt(0) centre

Fluorinated (hetero)aromatic ethers undergo O–Me oxidative addition to form Pt–CH₃ complexes at Pt(PCyp₃)₂ in preference to C–H or C–F activation.