Photocatalytic behaviour of tantalum (V) phthalocyanines in the presence of gold nanoparticles towards the oxidation of cyclohexene

This paper presents the photocatalytic oxidation of cyclohexene using (OH)(3)TaPc derivatives in the absence or presence of gold nanoparticles (AuNPs). The photochemical parameters that include photodegradation (Phi(P)) and singlet oxygen (Phi(Delta)) quantum yields are also reported in this work. The Phi(Delta) values were 0.47 and 0.36 for complexes 1a and 1b, respectively. The Phi(Delta) values improved drastically in the presence of AuNPs to 0.75 and 0.88, respectively. The Phi(P) values ranged from 1.02 to 2.45 x 10(-6), showing stability of TaPc derivatives in the absence and presence of AuNPs. The photocatalytic products identified using gas chromatograph (GC) are cyclohexene oxide, 2-cyclohexen-1-ol, 2-cyclohexene-1-one and 1,2-cyclohexanediol. The percentage conversion values were higher in the presence of AuNPs. Singlet oxygen was determined to be the main agent involved in the photocatalytic oxidation of cyclohexene. The product yield percentage values for both TaPc complexes (1a and 1b) and TaPc in the presence of AuNPs ranged from 6.3 to 21.2%. (C) 2010 Elsevier B.V. All rights reserved.