Synthesis of 5,10,15,20-meso-unsubstituted and 5,10,15,20-meso-substituted-21,23-ditellura/diselena core-modified porphyrinogens: oxidation and detection of mercury(ii)

Abstract

Tellurium and selenium incorporated 5,10,15,20-meso-unsubstituted-21,23-ditellura/diselena core-modified porphyrinogens (N₂Te₂ and N₂Se₂), 5,10,15,20-meso-unsubstituted-21-tellura/selena core-modified porphyrinogens (N₃Te and N₃Se) and fully substituted meso-carbons porphyrinogens (N₂Te₂, N₂Se₂ and higher analogs) are synthesized by 3 + 1 condensation of tellurophene/selenophene dipyrranes and their corresponding diols in the presence of BF₃–etharate or BF₃–methanol. The meso-unsubstituted and substituted porphyrinogens were oxidized with chloranil/0.1% aqueous FeCl₃ in CHCl₃ at room temperature to obtain the corresponding porphines and porphyrins which are further reduced to corresponding chlorin and bacteriochlorin, whereas the fully meso-substituted porphyrinogens were found to be good ligands for Hg²⁺. The structures of the products were characterized by IR, ¹H, ¹³C, ¹²⁵Te, ⁷⁷Se NMR, CHN analysis, mass spectrometry and single-crystal XRD.