Photophysical and electrochemical behavior of thin solid films based on a three-dimensional ruthenium complex network

RuL32+ (L = 2,2'-bipyridine-4,4'-diphosphonic acid) thin solid films were fabricated by three-dimensional linking between the phosphonic acid substituents of L and Zr(O)Cl-2. The RuL3 chromophores in the films are electronically independent of each other in the ground state and give emission spectra essentially identical to that of RuL32+ in solution, although the emission lifetime is much shorter. The films are electrochemically active, showing pseudo-reversible oxidation behavior in cyclic voltammetry. A preliminary attempt has been made to apply these films to photoelectrochernical cells.