Covalently linked acceptor-donor systems based on isoquinoline N-oxide acceptor: photoinduced electron transfer produces dual-channel luminescent systems that evolve chemically to photohydroxylation of the aromatic donor

A molecular 1 : 2 demultiplexer

A dual-channel fluorescent compound runs as a 1 : 2 digital demultiplexer (DEMUX) which can drive a single signal (proton) to two different destinations as a fluorescent photonic response; each fluorescent channel can be activated independently by careful selection of the excitation wavelength.

Fe(II), Ru(II) and Re(I) complexes of endotopic, sterically non-hindering, U-shaped 8,8'-disubstituted-3,3'-biisoquinoline ligands: syntheses and spectroscopic properties

The redox behaviour, optical-absorption spectra and emission properties of U-shaped and elongated disubstituted biisoquinoline ligands and of derived octahedral Fe(ii), Ru(ii), and Re(i) complexes are reported. The ligands are 8,8'-dichloro-3,3'-biisoquinoline (1), 8,8'-dianisyl-3,3'-biisoquinoline (2), and 8,8'-di(phenylanisyl)-3,3'-biisoquinoline (3), and the complexes are [Fe(3)(3)](2+), [Fe(2)(3)](2+), [Ru(1)(phen)(2)](2+), [Ru(2)(3)](2+), [Ru(3)(3)](2+), [Re(2)(py)(CO)(3)](+), and [Re()(py)(CO)(3)](+). For the ligands, the optical properties as observed in dichloromethane are in line with expectations based on the predominant (1)pipi* nature of the involved excited states, with contributions at lower energies from (1)npi* and (1)ILCT (intraligand charge transfer) transitions. For all of the Fe(ii), Ru(ii), and Re(i) complexes, studied in acetonitrile, the transitions associated with the lowest-energy absorption band are of (1)MLCT (metal-to-ligand charge transfer) nature. The emission properties, as observed at room temperature and at 77 K, can be described as follows: (i) the Fe(ii) complexes do not emit, either at room temperature or at 77 K; (ii) the room-temperature emission of the Ru(ii) complexes (phi(em) > 10(-3), tau in the micros range) is of mixed (3)MLCT/(3)LC character (and similarly at 77 K); and (iii) the room-temperature emission of the Re(i) complexes (phi(em) approximately 3 x 10(-3), tau < 1 ns) is of (3)MLCT character and becomes of (3)LC (ligand-centered) character (tau in the ms time scale) at 77 K. The interplay of the involved excited states in determining the luminescence output is examined.

Photochemical Smiles Rearrangement and Meisenheimer Complex Formation Catalyzed by Hydroxide Ion via Electron Hole Transfer Catalysis

[reactions: see text] Photochemical para-to-nitro Smiles rearrangement and para-to-nitro Meisenheimer complex formation occurs for nitrophenoxyethylamines with high concentrations of hydroxide ion in aqueous solution. Both photoreactions show first-order dependence on hydroxide ion concentration, but the mechanism involving hydroxide ion does not involve acid-base catalysis. The reactions take place from the triplet excited states of the nitrophenyl ethers. Analysis of quantum yields and kinetics is consistent with an electron hole transfer catalysis mechanism.

A Natural-Product-Inspired Photonic Logic Gate Based on Photoinduced Electron-Transfer-Generated Dual-Channel Fluorescence

[structure: see text] Modified 1-benzylisoquinoline N-oxides can operate as molecular logic gates. The combination of dual-channel fluorescence emissions and the preferred interaction for selected chemical inputs allows one to design multifunction and self-reprogrammable molecular logic gates.