Metalloid porphyrins and phthalocyanines

Application of the electronic spectra of porphyrins for analytical purposes: The effects of metal ions and structural distortions

“…The redshifts of absorption bands induce those of the emission bands too, and as further consequences of distortion, the quantum yields and the lifetimes of the fluorescences decrease due to the acceleration of non-radiative decays [24]. Considering the consequences of distortions as steric effects in the metalation of porphyrins, we disproved the validity of the widespread categorization method of metalloporphyrins introduced by Gouterman and based exclusively on the electronic structure of metal center [25]. Instead, we declared the distorting effect originating from the size and the position of the metal center compared to the cavity of the ligand as the primary aspect [19].…”

“…Also a ruffled-like deformation of the periphery superposes on this high doming, which results in a large redshift, called also as bathochromic or (not quite correctly) hyperchromic effect (bathochromic effect means the increase of the wavelength, while hyperchromic effect means the increase of the absorbance or molar extinction coefficient). Considering the spectral effects, the complexes possessing so highly redshifted absorption bands were named by Gouterman as hyper-porphyrins [25]. According to his definition, this category involves the complexes, whose absorption spectra can not be described with his 4 MO model [83].…”

Metallophthalocyanine dimers incorporating five-atom covalent bridges

“…These soluble, unsymmetrical, mononyclear phthalocyanines contained the necessary handle, a hydroxy functional group, which could be used to attach the phthalocyanine to electrodes ( 13,14). The synthesis of a very soluble mononuclear phthalocyanine in our earlier studies (1 1, 12) and the development of chromatographic methods for the separation of phthalocyanines in general (1 2) has enabled us to contemplate the syntheses of the hitherto unknown binuclear phthalocyanines.…”

Lead structures for applications in photodynamic therapy. 5. Synthesis and biological evaluation of water soluble phosphorus(V) 5,10,15,20-tetraalkylporphyrins for PDT

“…Here, we present the use of P(V) porphyrin complexes which offer such a possibility, as they allow not only the preparation of new drug candidates but simple improvements of existing drugs through P(V) complexation, i.e., water solubility [18], better uptake and potentially less side effects. P(V) porphyrin complexes are known but their exploitation in terms of PDT has been limited thus far [18,19,20,21,22,23,24,25]. We found that through P(V) complexation of simple meso tetrasubstituted porphyrins both the water solubility and the in vitro cytotoxicity of the photosensitizer can be drastically improved with respect to the non-complexed form.…”

“…Meso aryl and β-octaethyl P(V) porphyrins have been prepared before, mostly for coordination studies, redox chemistry investigations, and structural analyses [19,20,21,22,23,24]. The procedure we adopted followed that developed for P(V) insertion of 2,3,7,8,12,13,17,18-octaethylporphyrin derivatives, whereby PCl 3 acts as a more effective reagent for insertion over POCl 3 due to a lower phosphorus oxidation state [23,24].…”