Spectral investigation of phthalocyanine complexes of high-valence silver and their aggregates

Several novel silver(II) complexes ligating a tetra-substituted phthalocyaninate, [Ag(tbpc)] (where tbpc denotes tetra-tert-butylphthalocyaninate), [Ag(tppc)] (tppc = tetrakis(2,6-dimethylphenoxy)phthalocyaninate), [Ag(tObpc)] (tObpc = tetra-n-butoxyphthalocyaninate), and [Ag(tpySpc)] (tpySpc = tetrakis(4-pyridylthio)phthalocyaninate) have been synthesized and characterized by elemental analyses, MALDI-TOF MS, optical absorption, and magnetic circular dichroism (MCD) spectroscopy. Although all the compounds are well soluble in common organic solvents, concentration studies on their optical spectra in solutions have found that they are prone to strongly aggregate in a cofacial manner (i.e., H-aggregate). Silver(II) complexes, which are essentially non-fluorescent, are readily demetallated in the presence of appropriate reductant (e.g., I− or BH4−) to liberate the corresponding macrocyclic ligand, which emits intense red fluorescence. Chemical oxidation by using NOBF4 generates the corresponding silver(III) species. Several novel silver(II) complexes ligating a tetra-substituted phthalocyaninate (AgPcs) have been synthesized. Spectral properties of AgPcs, their molecular assembles, as well as their oxidized species have been investigated. These AgPcs are capable of oxidizing weak electron donors such as iodide. [Display omitted] •Syntheses of four novel silver-phthalocyanines (AgPcs).•Spectral properties of AgPcs with the metal in higher oxidation states (+2/+3).•Spectral studies on supramolecular interactions between AgPc molecules.•Solution chemistry involving AgPcs.