We report on seven 4-ferrocenylphenyl-substituted tritylium dyes Fc-C 6 H 4 -C + Ar 2 with either unlinked or interlinked aryl residues Ar, including congeners with six-membered (thio)xanthylium and seven-membered (dihydro)dibenzo[a,d]cycloheptatrienylium motifs. All complexes are intensely colored and show more or less intense absorption bands owing to charge transfer from the 4-ferrocenylphenyl donor to the C + Ar 2 acceptor unit as well as reversible electrochromism upon reduction and oxidation. The spectral profiles and redox potentials depend on whether or not the methylium center is incorporated into a 14-πelectron arene system. T-dependent EPR spectroscopy indicates that their one-electron-reduced neutral radicals dimerize. The ensuing monomer−dimer equilibria were studied by quantitative spincounting methods, which revealed an unexpectedly large extent of 85.0−99.6% of dimerization.

Nylon-6 is selectively depolymerized to the parent monomer ɛ-caprolactam by the readily accessible and commercially available lanthanide trisamido catalysts Ln(N(TMS) 2 ) 3 (Ln = lanthanide). The depolymerization process is solvent-free, near quantitative, highly selective, and operates at the lowest Nylon-6 to ɛcaprolactam depolymerization temperature reported to date. The catalytic activity of the different lanthanide trisamides scales with the Ln 3 + ionic radius, and this process is effective with post-consumer Nylon-6 as well as with Nylon-6 + polyethylene, polypropylene or polyethylene terephthalate mixtures. Experimental kinetic data and theoretical (DFT) mechanistic analyses suggest initial deprotonation of a Nylon terminal amido NÀ H bond, which covalently binds the catalyst to the polymer, followed by a chain-end back-biting process in which ɛcaprolactam units are sequentially extruded from the chain end.

Nylon-6 is selectively depolymerized to the parent monomer ɛ-caprolactam by the readily accessible and commercially available lanthanide trisamido catalysts Ln(N(TMS) 2 ) 3 (Ln = lanthanide). The depolymerization process is solvent-free, near quantitative, highly selective, and operates at the lowest Nylon-6 to ɛcaprolactam depolymerization temperature reported to date. The catalytic activity of the different lanthanide trisamides scales with the Ln 3 + ionic radius, and this process is effective with post-consumer Nylon-6 as well as with Nylon-6 + polyethylene, polypropylene or polyethylene terephthalate mixtures. Experimental kinetic data and theoretical (DFT) mechanistic analyses suggest initial deprotonation of a Nylon terminal amido NÀ H bond, which covalently binds the catalyst to the polymer, followed by a chain-end back-biting process in which ɛcaprolactam units are sequentially extruded from the chain end.