An Expedient Synthesis of Perfluorinated Tetraazamacrocycles: New Ligands for Copper-Catalyzed Oxidation under Fluorous Biphasic Conditions

Selective Alkane Hydroxylation in a Fluorous Solvent System Catalyzed by a Fluorocarbon-Soluble Transition-Metal Catalyst

Hydroxylation of aliphatic hydrocarbons requires highly reactive oxidants, but their strength can lead to undesired oxidation of the initially formed alcohols and solvents, undermining the product selectivity. To address these problems, we developed a novel catalytic system using fluorocarbon solvents. A cobalt complex supported by the fluorinated ligand, N,N,N',N',N″-pentakis-[CF3(CF2)7(CH2)3]-diethylenetriamine (Rf-deta), acts as an efficient catalyst [turnover number (TON) = 1203, turnover frequency = 51 ± 1 min-1] for cyclohexane hydroxylation with the m-chloroperbenzoic acid oxidant, achieving high alcohol selectivity (96%). Overoxidation to form cyclohexanone is minimized due to the separation of cyclohexanol from the reaction phase, comprising perfluoromethylcyclohexane and α,α,α-trifluorotoluene. The catalyst hydroxylates primary carbons (5 examples) and exhibits significant reactivity toward the terminal C-H bond of normal hexane (TON = 13). This system extends to the hydroxylation of the gaseous substrate butane, yielding the corresponding alcohols.

Carbazole-based N4-donor Schiff base macrocycles: obtained metal free and as Cu(ii) and Ni(ii) complexes

Practical multi-step routes to 1,8-diformylcarbazole head units, and the first examples of Schiff base macrocycles derived from them, are reported. Like porphyrins, both macrocycles are shown to impose a strong ligand field.

Oxidation of hydrocarbons with H2O2/O2 catalyzed by osmium complexes containing p-cymene ligands in acetonitrile

Osmium π-complexes containing p-cymene ligands efficiently catalyze (TONs up to 200 000) the oxidation of alkanes to alkyl hydroperoxides with H₂O₂.