Modulating Electron Transfer in a Simple Bichromophoric System Employing Axial-Ligation as an Organising Precept

A naphthalene diimide acceptor 1 bearing a pyridine group linked directly ( a series) or through a —CH 2 CH 2 — spacer ( b series) coordinated axially to a metallotetraarylporphyrin (MP) undergoes fast photoinduced electron transfer (in the case of MP = Zn(II)TTP) while the kinetically more stable ruthenium complexes (MP = Ru(CO)TPP) have been used to illustrate the correlation between the distance of probe protons from the porphyrin plane and the change in chemical shift (Δ δ ) upon coordination. Changes in the emission spectra at 650 nm ( λ ex = 400 nm) upon the addition of Zn(II) ions and/or 1b to TTPH 2 can be interpreted in a truth table to illustrate a NAND gate.