Trimellitic anhydride- and pyromellitic dianhydride-originated tetrakis/octakis(octyloxycarbonyl)phthalocyaninato metal complexes

1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) catalyzed esterification with 1-bromooctane over tetrakis/octakis(carboxy)phthalocyanines originated from trimellitic anhydride and pyromellitic dianhydride led to the isolation of a series of 2(3),9(10),16(17),24(25)-tetrakis(octyloxycarbonyl)phthalocyaninato metal complexes M[Pc(COOC8H17)4] (Mdouble bond; length as m-dashCo, Ni, Cu, Zn) (1a–1d) and 2,3,9,10,16,17,24,25-octakis(octyloxycarbonyl)phthalocyaninato metal complexes M[Pc(COOC8H17)8] (Mdouble bond; length as m-dashCo, Cu) (2a, 2c). In addition to elemental analysis, these tetrakis/octakis(octyloxycarbonyl)-substituted phthalocyanines were characterized by a series of spectroscopic methods including MALDI-TOF mass, 1H NMR and 2D COSY, UV–vis, and IR spectroscopy. The tetrakis(octyloxycarbonyl)-substituted phthalocyanines represent the first example of 2(3),9(10),16(17),24(25)-tetrakis(octyloxycarbonyl)phthalocyaninato metal complexes that have ever been unambiguously characterized by mass and NMR spectroscopy.