Synthesis of pyridylporphyrin metal complexes

Abstract

Trtraarylporphyrins carring 4-pyridyl (Py) and phenyl (P) groups at mesopositions have been synthesized and characterized by various spectroscopic methods. this synthesis was performed by reacting pyrrole, benzaldehyde, and 4-pyridine carboxaldehyde at a 4:2:2 ratio giving 5-(4-pyridyl)-10,15,20-triphenylporphyrin (MPyTPP, 8) as a major product in 36% yield. among the porphyrins prepared, 5,10,15,20-tetraphenylporphrin (TPP, 1) and MPyTPP (8) have been shown to from complexes with acetate salts of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and chloride salt of Fe (III) in either chloroform or N,N-dimethylformamide. IH NMR measurements of all these metalloporphyrins revealed that the signal of internal N-H protons within the inner core of porphyrin rings between -2.70 to -2.90 ppm was absent, supportive of replacements of these pro by metal atoms. UV-Visible spectra showed that the four Q-bands of the free porphyrin base were reduced to only one or two peaks upon complexatioms. dimeric porphrin formed by a side to face complexation, (ZnTPP) (MPyTPP) (22) and (CoTPP)(MPyTPP) (23) were synthesized insitu in NMR tubes. IH MNR spectra indicated that pyridyl protons of MPyTPP showed large upfiled shifts. the corresponding molecular weights of the porhyrin complexes and the dimer film has been used as optical-responsive chemically interacing materials for the detection of various vaporized alcohols.