Synthesis of 2,3,9,10,16,17,23,24-octaalkynylphthalocyanines and the effects of concentration and temperature on their H-1 NMR spectra

The syntheses of 3,4- and 4,5-diiodophthalonitriles are described. Coupling of the latter compound with Pd(PPh(3))(2)Cl-2 and 1-octyne, 1-heptyne, 1-hexyne, 1-pentyne, and 3,3-dimethyl-1-butyne gave a series of 4,5-dialkynylphthalonitriles. Hydrogenation of 4,5-bis(1-pentynyl)phthalonitrile and 4,5-bis(3,3-dimethyl-1-butynyl)phthalonitrile gave 4,5-dipentylphthalonitrile and 4,5-bis(3,3-dimethylbutyl)phthalonitriles. Condensation of the dialkynylphthalonitriles with lithium 1-pentoxide in 1-pentanol gave 2,3,9,10,16,17,23,24-octaalkynylphthalocyanines, while intervention of the intermediate dilithium phthalocyanines with zinc acetate gave the related zinc(II) phthalocyanines. H-1 NMR spectroscopy of these octaalkynylphthalocyanines exhibited large chemical shifts (1-2 ppm) of the internal and aromatic protons at concentrations ranging from 10(-2) to 10(-5) M and at temperatures from 27 to 147 degrees C. The effects of aggregation phenomena are discussed. The importance of reporting concentration and temperature values for NMR spectra of phthalocyanines is stressed.