Metallomimetic Chemistry of a Cationic, Geometrically Constrained Phosphine in the Catalytic Hydrodefluorination and Amination of Ar–F Bonds

Abstract

The synthesis, isolation, and reactivity of a cationic, geometrically constrained σ 3 -P compound in the hexaphenylcarbodiphosphoranyl-based pincer-type ligand (1 + ) are reported. 1 + reacts with electron-poor fluoroarenes via an oxidative additiontype reaction of the C−F bond to the P III -center, yielding new fluorophosphorane-type species (P V ). This reactivity of 1 + was used in the catalytic hydrodefluorination of Ar−F bonds with PhSiH 3 , and in a catalytic C−N bond-forming cross-coupling reactions between fluoroarenes and aminosilanes. Importantly, 1 + in these catalytic reactions closely mimics the mode of action of the transition metal-based catalysts.

Reactivity of a Strictly T‐Shaped Phosphine Ligated by an Acridane Derived NNN Pincer Ligand

“…Reaction of ONO and NPN pincer compounds towards oxygen and oxygen atom transfer reagents was reported to result in ligand disassembly and ligand oxidation, respectively [21,51] . By contrast, a CCC ligated phosphenium cation showed phosphorus centered oxidation [33] . When 4 i Pr is reacted with oxygen at elevated temperatures, the phosphorus oxide 7 is formed as evidenced by 31 P{ 1 H} and 1 H NMR spectroscopy (Scheme 2, 31 P{ 1 H} NMR=37.4 ppm, 55 % isolated yield).…”

“…[21,51] By contrast, a CCC ligated phosphenium cation showed phosphorus centered oxidation. [33] When 4 iPr is reacted with oxygen at elevated temperatures, the phosphorus oxide 7 is formed as evidenced by 31 P{ 1 H} and 1 H NMR spectroscopy (Scheme 2, 31 P{ 1 H} NMR = 37.4 ppm, 55 % isolated yield). 7 can also be prepared upon reaction of 4 iPr with pyridine N-oxide (57 % isolated yield).…”

Redox-active carborane clusters in bond activation chemistry and ligand design

“…3,20,21 As another example, cycling between P(III) and P(V) states in geometrically constrained phosphorus compounds affords the possibility of oxidative addition and reductive elimination in a way that mimics the reactivity of transition metal complexes. 6,[22][23][24] The redox transformations in main group systems can be centered at a single atom (carbon or phosphorus atoms in the examples above), or they can occur through the participation of larger molecular fragments. The focus of this feature article is Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St, Columbia, South Carolina 29208, USA.…”

“…3,20,21 As another example, cycling between P( iii ) and P( v ) states in geometrically constrained phosphorus compounds affords the possibility of oxidative addition and reductive elimination in a way that mimics the reactivity of transition metal complexes. 6,22–24…”

Four-Electron Reduction of O2 Using Distibines in the Presence of ortho-Quinones

“…Inspired by the prevalence of bifunctional 9,9-dimethylxanthene-based constructs in artificial oxygen reduction catalysts, we have decided to focus on distibines related to F (Scheme ), which, as per our prior investigations, readily reacts with the electron-poor ortho -quinone o -chloranil to afford the corresponding distiborane G . In this article, we show that such distibines, when in the presence of an electron-rich ortho -quinone, can reduce O 2 , broadening the type of redox reactions that group 15 systems can mediate …”