B−C Bond Cleavage of BAr_FAnion Upon Oxidation of Rhodium(I) with AgBAr_F. Phosphinite Rhodium(I), Rhodium(II), and Rhodium(III) Pincer Complexes

Abstract

A rare case of BAr F anion cleavage (BAr F -) tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) by a metal complex is described. Reaction of the Rh(I) dinitrogen complexes 5a,b and 6a,b, based on the phosphinite pincer ligands {C 6 H 4 [OP( t Bu) 2 ] 2 } (2), with 2 equiv of AgBAr F at room temperature resulted in B-C bond cleavage of one of the BAr F anions and aryl transfer to afford the Rh(III) aryl complexes 7 and 8, respectively. The X-ray structure of 8 revealed a square-pyramidal geometry with a coordinated acetone molecule. The aryl transfer occurred as a result of electrophilic attack by unsaturated Rh(III) on one of the aryl rings of the BAr F anion. Utilizing different solvents yielded the same product, except when CH 3 CN was used, in which case one-electron oxidation took place, yielding complex 9. Treatment of 6a,b with 1 equiv of AgX (X ) BAr F , BF 4 , PF 6 ) resulted in a one-electron oxidation to yield the paramagnetic Rh(II) complexes 9-11, respectively. Complex 11 was characterized by X-ray diffraction, revealing a mononuclear square-planar Rh(II) complex.

Catalysis of Kumada–Tamao–Corriu coupling by a (POCOP)Rh pincer complex

“…90% purity, with no identification of impurities, from 4 and [(COE) 2 RhCl] 2 . 12 In our hands, the same synthesis also gave impure 5 (ca. 80% purity) and a synthesis using [(COD)RhCl] 2 gave even less pure 5 (50-60% pure).…”

Synthesis and Applications of Perfunctionalized Boron Clusters

“…99 The kinetic stability of these perfuctionalized boron clusters is particularly relevant to (cationic) transition metal catalysis, since even the widely used BAr F anion ([B(C 6 F 5 ) 4 ] − ) has been shown to engage in aryl ring transfer in the presence of transition metal cations. 100,101,102 …”

Mild and Selective H/D Exchange at the β Position of Aromatic α‐Olefins by N‐Heterocyclic Carbene–Hydride–Rhodium Catalysts

“…Thus, we chose 1,3-bis-(2,6-diisopropylphenyl)imidazol-2-carbene (IPr) as encumbered NHC ligand and 8-quinolinol as a suitable hydride source upon oxidative OÀH addition. [8] Treatment of the dimer [Rh(m-Cl) [9] Crystallization of 2 from coordinating solvents gave the saturated species [RhClH(k 2 O,N-C 9 H 6 NO)(IPr)(S)] [S = methanol (3); acetonitrile (4)]. The structure of 3 was confirmed by an X-ray diffraction analysis.…”