Electrochemical and photophysical characterization of non-peripherally-octaalkyl substituted dichlorotin(IV) phthalocyanine and tetrabenzotriazaporphyrin compounds

Abstract

Three non-peripherally substituted tin(IV) macrocylic compounds, octahexylphthalocyaninato dichlorotin(TV) (3a), octahexyltetrabenzo-5,10,15-triazaporphyrinato dichlorotin(IV) (3b) and octadecylphthalocyaninato dichlorotin(IV) (3c) were synthesized and their photophysical and electrochemical behavior studied. Complex 3b, containing a CH group in place of one of the aza nitrogen atoms of the phthalocyanine core, shows a split Q-band due to its lower symmetry. The triplet state quantum yields were found to be lower than would be expected on the basis of the heavy atom effect of tin as the central metal for phthalocyanine derivatives (3a and 3c). In contrast, 3b shows a triplet quantum yield Phi(T) = 0.78. The triplet state lifetimes were solvent dependent, and were higher in tetrahydrofuran than in toluene. Cyclic voltammetry and spectroelectrochemistry of the complexes revealed only ring-based redox processes

Low Symmetry Phthalocyanines and Their Analogues

“…415 Some CV and DPV data have also been reported. 455,459,465,466 Kobayashi, Stuzhin, and co-workers 455 recorded CV and DPV data for Cu II Pz and Cu II oppDAP, together with the cyclic voltammograms of copper octaethylporphyrin (Cu II OEP) and Cu II Pz in o-dichlorobenzene (Figure 34). As the number of aza-nitrogen atoms increases Cu II oppDAP, and Cu II Pz are 2.36, 2.17, and 2.19 V, respectively, while the corresponding values for OEP derivatives are reported to be 2.25 ( 0.15 V. 482 This demonstrates that the presence of the aza-nitrogens has only a minor effect on the magnitude of the HOMO-LUMO band gap as would be anticipated based on their similar Q band wavelengths.…”

Porphyrin Complexes with Highly Electronegative Metals – A New Chapter in Nucleophilic Substitution of Hydrogen?

“…Tin complexes: meso-tetraphenylporphyrindichlorotin(IV) and octaethylporphyrin-dichlorotin(IV) systems. We tried to verify the above concept using another relatively easily available porphyrin complexes (dichlorotin derivatives; e Sn = 1.96): octaethylporphyrin-dichlorotin(IV) (8) and mesotetraphenylporphyrin-dichlorotin(IV) (9). They were synthesized on the basis of two literature reports.…”

“…They were synthesized on the basis of two literature reports. [8,9] Nevertheless, some modifications were introduced (sulfolane as a solvent, 170-200°C, ca 1 h, 68-100%; see Experimental). Confirmation of their structures was not a trivial problem.…”

“…Also octaethylporphyrin was obtained according to known procedure. [13] Octaethylporphyrin-dichlorotin(IV) complex (8) was prepared therefrom according to modified procedure described in the literature for similar compounds [8,9] [Octaethylporphyrin (50 mg, 0.094 mmol) and SnCl 2 2H 2 O (31 mg, 0.137 mmol) in sulfolane (4 mL) were heated (under argon) at 170°C in a round-bottomed light-shielded flask equipped with a reflux condenser over a period of 1.5 h. Then, the reaction mixture was cooled to room temperature and to this mixture CHCl 3 (30 mL) was added. The organic layer was washed with water (440 mL) and dried with anhydrous MgSO 4 .…”

Tetrabenzoporphyrin and -mono-, -cis-di- and Tetrabenzotriazaporphyrin Derivatives: Electrochemical and Spectroscopic Implications of meso CH Group Replacement with Nitrogen

“…A recent review reports fewer than 150 papers have been published on these compounds . However, of particular relevance to the present paper are those of Lever and Leznoff who described some electrochemical, spectroelectrochemical, and Langmuir–Blodgett film deposition studies of peripherally substituted tetrabenzotriazaporphyrins, while Nyokong reported on the electrochemical and photophysical properties of tin complexes of tetrabenzotriazaporphyrins. Kobayashi, Mack, and co-workers reported on the magnetic circular dichroism properties in relation to time-dependent density functional theory (TD-DFT) calculations of related copper complexes …”