Synthesis, electrochemical and photophysical properties of phthalocyaninato oxotitanium(IV) complexes tetra-substituted at the alpha and beta positions with arylthio groups

摘要

The synthesis, electrochemical and photophysical properties of the following tetra-substituted thiol oxotitanium phthalocyanines are reported for the first time: 1,( 4)-(tetraphenylthiophthalocyaninato)titanium(IV) oxide (5a); 1,( 4)-(tetrabenzylthiophthalocyaninato) titanium( IV) oxide (5b); 2,( 3)-( tetraphenylthiophthalocyaninato) titanium( IV) oxide (6a) and 2,( 3)-(benzylthiophthalocyaninato)titanium( IV) oxide (6b). Cyclic voltammograms of all four complexes are similar, with three reversible reduction couples each involving a one electron transfer process. The first two reductions were confirmed by spectroelectrochemistry to be metal-based reductions due to (TiPc-2)-Pc-IV/(TiPc-2)-Pc-III and (TiPc-2)-Pc-III/(TiPc-2)-Pc-II redox processes, while the last reduction was confirmed to be a ring-based reduction due to (TiPc-2)-Pc-II/(TiPc-3)-Pc-II. Low fluorescence quantum yields (0.05 - 0.14), relatively long triplet lifetimes ( 150 - 210 mu s) and triplet yields (0.31 to 0.82) were observed.