119273-08-4Relevant academic research and scientific papers
Photoreactivity of σ-bonded metalloporphyrins. 1. Formation of zwitterionic indium and gallium porphyrin complexes in tetrahydrofuran
Kadish,Maiya,Xu
, p. 2518 - 2523 (2008/10/08)
Continuous irradiation and laser-flash photolysis experiments were carried out in THF on σ-bonded indium and gallium porphyrins of the type (P)M(R), where P is the dianion of tetraphenylporphyrin (TPP) or octaethylporphyrin (OEP), M is In or Ga, and R is CH3, C2H5, C4H9, CH(CH3)2, C(CH3)3, CH=CHC6H5, or C≡CC6H5. Steady-state photolysis of (P)M(R), where R = CH3, C2H5, C4H9, CH(CH3)2, or C(CH3)3, leads to photodissociation of the metal-carbon bond. In contrast, indium and gallium porphyrins with σ-bonded CH=CHC6H5 or C≡CC6H5 groups do not undergo this photodissociation reaction. Laser photolysis studies were carried out both in the presence and in the absence of ferrocene and indicate that the photoreaction occurs via a triplet state originating from the porphyrin macrocycle. The resulting ESR spectra obtained after photolysis of (TPP)In(C2H5) in THF are compared with ESR spectra obtained after electrochemical reduction of (TPP)InCl. On the basis of these results, a photochemical generation of zwitterionic metalloporphyrin radicals of the type (P)-In+ is demonstrated to occur in THF. Similarly, the (P)Ga(R) complexes also form a zwitterionic photoproduct upon irradiation as evidenced by ESR and UV-visible spectra. The photoreactivity of (P)In(R) and (P)Ga(R) is discussed with respect to the porphyrin macrocycle, the σ-bonded R group, and the solvent polarity.
