Ferrocene, Fc, and cobaltocenium hexafluorophosphate, CcPF6, have been recommended for use as internal reference redox couples in room-temperature ionic liquids (RTILs), as well as in more conventional aprotic solvents. In this study, the electrochemical behavior of Fc and CcPF6 is reported in eight commonly used RTILs; [C2mim][NTf2], [C4mim][NTf2], [C4mim][BF4], [C4mim][PF6], [C4mim][OTf], [C4mim][NO3], [C4mpyrr][NTf2], and [P14,6,6,6][FAP], where [C n mim]+ = 1-butyl-3-methylimidazolium, [NTf2]- = bis(trifluoromethylsulfonyl)imide, [BF4]- = tetrafluoroborate, [PF6]- = hexafluorophosphate, [OTf]- = trifluoromethylsulfonate, [NO3]- = nitrate, [C4mpyrr]+ = N-butyl-N-methylpyrrolidinium, [P14,6,6,6 ]+ = tris(n-hexyl)-tetradecylphosphonium and [FAP]- = trifluorotris(pentafluoroethyl)phosphate, over a range of concentrations and temperatures. Solubilities and diffusion coefficients, D, of both the charged and neutral species were determined using double potential-step chronoamperometry, and CcPF6 (36.5−450.0 mM) was found to be much more soluble than Fc (27.5−101.8 mM). It was observed that classical Stokes−Einstein diffusional behavior applies for Fc and CcPF6 in all eight RTILs. Diffusion coefficients of Fc and CcPF6 were calculated at a range of temperatures, and activation energies calculated. It was also determined that D for Fc and CcPF6 does not change significantly with concentration. This supports the use of both Fc and CcPF6 to provide a well-characterized and model redox couple for use as a voltammetric internal potential reference in RTILs contrary to previous literature reports in the former case.

Recent developments in experimental and computational chemistry have identified a rapidly growing class of nucleophilic aromatic substitutions that proceed by concerted (cSNAr) rather than classical, two‐step, SNAr mechanisms. Whereas traditional SNAr reactions require substantial activation of the aromatic ring by electron‐withdrawing substituents, such activating groups are not mandatory in the concerted pathways.

The rhodium-catalyzed methylation of ketones has been accomplished using methanol as the methylating agent and the hydrogen-borrowing method. The sequence is notable for the relatively low temperatures that are required and for the ability of the reaction system to form α-branched products with ease. Doubly alkylated ketones can be prepared from methyl ketones and two different alcohols by using a sequential one-pot iridium- and rhodium-catalyzed process.

Reported herein is the use of catalytic [{Ir(cod)Cl}2] to facilitate hydrogen-borrowing reactions of ketone enolates with methanol at 65 °C. An oxygen atmosphere accelerates the process, and when combined with the use of a bulky monodentate phosphine ligand, interrupts the catalytic cycle by preventing enone reduction. Subsequent addition of pro-nucleophiles to the reaction mixture allowed a one-pot methylenation/conjugate addition protocol to be developed, which greatly expands the range of products that can be made by this methodology.