Sandwich Double-Decker Lanthanide(III) Intracavity Complexes Based on Clamshell-Type Phthalocyanine Ligands: Synthesis, Spectral, Electrochemical, and Spectroelectrochemical Investigations

Phthalocyanine compounds of novel type based on a bridged bis-ligand, denoted intracavity complexes, have been prepared. Complexation of clamshell ligand 1,1'-[benzene-1,2-diylbis(methanediyloxy)]bis[9(10),16(17),23(24)-tri-tert-butylphthalocyanine] (clam,tBuPc2H4, 1) with lanthanide(III) salts [Ln(acac)3]center dot n?H2O (Ln=Eu, Dy, Lu; acetylacetonate) led to formation of double-deckers clam,tBuPc2Ln (2?ac). Formation of high molecular weight oligophthalocyanine complexes was demonstrated as well. The presence of an intramolecular covalent bridge affecting the relative arrangement of macrocycles was shown to result in specific physicochemical properties. A combination of UV/Vis/NIR and NMR spectroscopy, MALDI-TOF mass-spectrometry, cyclic voltammetry, and spectroelectrochemistry provided unambiguous characterization of the freshly prepared bis-phthalocyanines, and also revealed intrinsic peculiarities in the structureproperty relationship, which were supported by theoretical calculations. Unexpected NMR activity of the paramagnetic dysprosium complex 2?b in the neutral p-radical form was observed and examined as well.