New fluorescent manganese(III) phthalocyanines bearing non-peripherally octa-(3-pyridin-3-ylpropoxy) and (4-pyridin-3-ylpropoxy) for the sensitive determination of Pd2+in real water samples

In this study, 3,6-bis(3-pyridin-3-ylpropoxy)phthalonitrile (1), 3,6-bis(3-pyridin-4-ylpropoxy)phthalonitrile (2), {1,4,8,11,15,18,22,25-octakis[3-pyridin-3-ylpropoxy]-phthalocyaninato} manganese(III) chloride (1a), {1,4,8,11,15,18,22,25-octakis[3-pyridin-4-ylpropoxy]-phthalocyaninato} manganese(III) chloride (2a) were synthesized and characterized with various techniques. Then, the affinities of the two new fluorescent manganese(III) phthalocyanines 1a and 2a with a range of metal ions were investigated. Manganese(III) phthalocyanine (MnPc) 1a selectively forms a complex with Pd2+ which exhibits intense fluorescence quenching (lambda ex/lambda em = 390/466 nm). 1a has been used as a fluorescent reagent to determine Pd2+ in real water samples. The samples of spiked water showed no matrix effect for Pd2+ determination in the working conditions. The proposed method, which is simple, fast, and sensitive, is good enough to recover Pd2+ at a concentration of 13.3 ng/mL. The detection limit (LOD) and the quantification limit (LOQ) of method are 3.0 ng/mL, and 9.1 ng/mL, respectively. The inter and intra-day precisions of method (RSD %) are 1.9 and 2.9. Therefore, 1a can detect and determine the hazardous pollutant Pd2+ in real water samples.