No abstract

Lanthanide ion (LnIII) complexes, [Ln(3Tcbx)2]3+ (LnIII=YbIII, NdIII, ErIII) are isolated with a new pyridine‐bis(carboxamide)‐based ligand with a 2,2′:5′,2′′‐terthiophene pendant (3TCbx), and their resulting photophysical properties are explored. Upon excitation of the complexes at 490 nm, only LnIII emission is observed with efficiencies of 0.29 % at 976 nm for LnIII=YbIII and 0.16 % at 1053 nm for LnIII=NdIII. ErIII emission is observed but weak. Upon excitation at 400 nm, concurrent 1O2 formation is seen, with efficiencies of 11 % for the YbIII and NdIII complexes and 13 % for the ErIII complex. Owing to the concurrent generation of 1O2, as expected, the efficiency of metal‐centered emission decreases to 0.02 % for YbIII and 0.05 % for NdIII. The ability to control 1O2 generation through the excitation wavelength indicates that the incorporation of 2,2′:5′,2′′‐terthiophene results in access to multiple sensitization pathways. These energy pathways are unraveled through transient absorption spectroscopy.

A new pyridine-bis(carboxamide)-based ligand with a bithiophene pendant, 2Tcbx, was synthesized.

The Belousov-Zhabotinskii (BZ) oscillating reaction mixture (malonic acid, bromate, and cerium ions in a strongly acidic medium) was studied. The oxidation state of the Ce +4 /Ce +3 catalyst fluctuates and drives the open-circuit potential (OCP) of the solution. Oscillatory profiles were analyzed using Au, Pt and C micro-and macro-electrodes to study the stages of induction, oscillating, and equilibrium. The oscillating behavior of the BZ system is transient, reaching a non-oscillating reductive steady-state. The time for achieving the oscillating state depends on the substrate (electrode material and size) while the number of oscillations is independent of substrate. Fast Fourier transform (FFT) analysis yields the fundamental frequency of the oscillating profile and evaluates the exponential falloff as the system approaches equilibrium. Also, Ce +4 concentration was tracked in the UV Vis. Chemical oscillations of the catalyst Ce +4 ion were reproduced using a numerical model, and its dynamical profile was analogous to the experimental data.