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Coumarin-substituted manganese phthalocyanines: synthesis, characterization, photovoltaic behaviour, spectral and electrochemical properties.

The synthesis and spectroscopic characterization of novel manganese(III) phthalocyanines bearing 7-oxy-4-(4-methoxyphenyl)-8-methylcoumarin or/and chloro groups have been achieved. The effect of alpha and beta substitution on the ligand- and metal-based reduction processes of the manganese phthalocyanine complexes and their interaction with dioxygen were investigated. The more effective interaction of the central metal of the beta coumarin substituted complex with dioxygen than that of its alpha substituted analogue was attributed to the hindrance of the interaction by the nonplanarity in the case of alpha substitution. Similarly, the aggregation tendency was lower in the case of alpha substitution. Among the fabricated coumarin-substituted manganese phthalocyanine donor layer and fullerene (C60) acceptor based photovoltaic heterojunction devices, the one containing 8 exhibited the best performance. The effect of the thickness of the active Pc layer on solar cell parameters has also been investigated. A nearly thickness independent open circuit voltage was observed.

Synthesis of selected 3- and 4-arylcoumarin derivatives and evaluation as potent antioxidants

A series of hydroxyl-, methoxy-, and acetoxy-substituted 3- and 4-arylcoumarins were synthesized. All title compounds were screened for their antioxidant capacity, ability to scavenge the 1,1-diphenyl-1-picrylhydrazyl (DPPH) radical, and ability to chelate iron ions. Furthermore, all derivatives were assessed using molecular properties prediction and drug likeness using Molinspiration. It was found that all studied derivatives were potential candidates for further research, as they complied with Lipinski’s rule of five for drug likeness. 3- or 4-arylcoumarins that possess two hydroxyl groups in ortho position, such as 4h, 5b, h, and 6a, had remarkable half-maximal effective concentration (EC50) for radical scavenging, with better performance than known antioxidants in DPPH and metal-chelating assays. In addition, the cupric-reducing antioxidant capacity and ferric-reducing antioxidant power of the synthesized compounds were investigated for antioxidant activity. Among them, 5g, h and 6a, b showed significantly better Trolox equivalent antioxidant capacity (TEAC) than standard compounds. The results demonstrate that the compounds with dihydroxyl groups at 6- and 7-positions of the benzopyrone ring of the arylcoumarin structure are the most active of the series as antioxidants. On the basis of these findings, these new coumarin derivatives are potential therapeutic candidates for pathogenesis of many diseases characterized by free-radical overproduction.

The effects of substituent position on kinetics of benzene vapour adsorption onto 3-phenylphenoxy substituted metal-free and metallo-phthalocyanines thin films

The preparation of metal-free, Zn(ii), In(iii), and Cu(ii)-phthalocyanines containing tetrakis-(3-phenylphenoxy) groups was achieved by employing 3-(3-phenylphenoxy)phthalonitrile (1) and 4-(3-phenylphenoxy)phthalonitrile (2) as starting materials. The phthalonitriles and phthalocyanines were characterized by elemental analysis, infrared, proton nuclear magnetic resonance, ultraviolet-visible, and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopic techniques. The effect of the substituent group on the kinetics of benzene vapour adsorption onto these novel compounds was examined using three kinetics models: the pseudo first-order model, the Elovich equation, and a simple adsorption-desorption model. Results show that the benzene adsorption kinetics strongly depend on the position of the substituent groups.