The synthesis, characterization, photophysical properties, theoretical calculations, and catalytic applications of 2,9-di(aryl)-1,10-phenanthroline copper(I) complexes are described. Specifically, this study made use of di(aryl)-1,10-phenanthroline ligands including 2,9-di(4-methoxyphenyl)-1,10-phenanthroline (1), 2,9-di(4-hydroxyphenyl)-1,10-phenanthroline (2), 2,9-di(4-methoxy-3-methylphenyl)-1,10-phenanthroline (3), and 2,9-di(4-hydroxy-3-methylphenyl)-1,10-phenanthroline (4). The 2 : 1 ligand-to-metal complexes, as PF6− salts, i.e., ([Cu·(1)2]PF6, [Cu·(2)2]PF6, [Cu·(3)2]PF6, and [Cu·(4)2]PF6) have been isolated and characterized. The structures of ligands 1 and 2 and complexes [Cu·(1)2]PF6 and [Cu·(3)2]PF6 have been determined by single-crystal X-ray analysis. The photoredox catalytic activity of these copper(I) complexes was investigated in an atom-transfer radical-addition (ATRA) reaction and the results showed fairly efficient activity, with a strong wavelength dependence. In order to better understand the observed catalytic activity, photophysical emission and absorption studies, and DFT calculations were also performed. It was determined that when the excitation wavelength was appropriate for exciting into the LUMO+1 or LUMO+2, catalysis would occur. On the contrary, excitations into the LUMO resulted in no observable catalysis. In light of these results, a mechanism for the ATRA photoredox catalytic cycle has been proposed.

Here we report the synthesis of metalated main-chain polypseudorotaxanes via ring-opening olefin metathesis copolymerization of macrocycles and metalated [2]catenanes. By varying the feed ratio of the macrocycle and the [2]catenate comonomers, we prepared metalated pseudorotaxane polymers with selected, predictable average linear densities of threaded macrocycles that ranged from 0% to 100%, thus allowing, for the first time, both full and fine control over this key parameter.

A conformationally dynamic chain compound that rapidly and reversibly samples both self-entangled and disentangled conformations, yet favors disentangled conformations, and an exclusively self-entangled [1]rotaxane were separately prepared and characterized. The conformationally dynamic state and the conformationally locked state were shown to reversibly and controllably interconvert under appropriate conditions, with an accompanying observable change in size that was calculated to approximate a 35% contraction in length upon capture of the self-entangled state.

The curious entropy-driven ring-opening metathesis polymerization (ED-ROMP) of macrocyclic olefins is highlighted. From early proof-of-principle reports through current state-of-the-art studies with an inclination towards materials applications, the known examples of these uncommon polymerizations are surveyed. The underpinnings of why these reactions work, what is and what is not to be expected and the prevailing practical measures to be taken to favor ED-ROMPs are discussed.

The synthesis, characterization, photophysical properties, theoretical calculations, and catalytic applications of 2,9-di(aryl)-1,10-phenanthroline copper(I) complexes are described. Specifically, this study made use of di(aryl)-1,10-phenanthroline ligands including 2,9-di(4-methoxyphenyl)-1,10-phenanthroline (1), 2,9-di(4-hydroxyphenyl)-1,10-phenanthroline (2), 2,9-di(4-methoxy-3-methylphenyl)-1,10-phenanthroline (3), and 2,9-di(4-hydroxy-3-methylphenyl)-1,10-phenanthroline (4). The 2:1 ligand-to-metal complexes, as PF6− salts, i.e., ([Cu·(1)2]PF6, [Cu·(2)2]PF6, [Cu·(3)2]PF6, and [Cu·(4)2]PF6) have been isolated and characterized. The structures of ligands 1 and 2 and complexes [Cu·(1)2]PF6 and [Cu·(3)2]PF6 have been determined by single-crystal X-ray analysis. The photoredox catalytic activity of these copper(I) complexes was investigated in an atom-transfer radical-addition (ATRA) reaction and the results showed fairly efficient activity, with a strong wavelength dependence. In order to better understand the observed catalytic activity, photophysical emission and absorption studies, and DFT calculations were also performed. It was determined that when the excitation wavelength was appropriate for exciting into the LUMO+1 or LUMO+2, catalysis would occur. On the contrary, excitations into the LUMO resulted in no observable catalysis. In light of these results, a mechanism for the ATRA photoredox catalytic cycle has been proposed.