Suhstituent effects an complex formation between variously substituted metallodeuteroporphyrins with filled 12~ orbitals and extraplanar hgand(s) ean be correlated by Hammett freeenergy plots. The slopes of these plots are positive and the correlation is high with substituent constants typical of resonance transmission of electronic effects. Conversely, correlation of the monoprotonation of substituted deuteroporphyrins requires KT,,, substituent constants, iudieative of the inductive mode of transmission_ Electron spin resonance spectra of the dg metalioporphyrins are in accord with the concept of the resonance mode of transm i&on sod suggest that the porphyrins with strongly electron withdrawing groups produce a relativeIy low ligand field A number of papers have been published recently presenting substituent effects on various properties of 2,4 and a ,B substituted deuteroporphyrin IX dimethyl ester derivatives. These have included variations in b&city in the free base porphyrin, [l, 21, variations in the stability constants for complex formation for various metalloporphyrins 13-51 and variat.ions in the observed electron spin resonance signal for copper (II) porphyrins [S]. It has been observed that the substituent effects on complex formation between various substituted nickel (II) deuteroporphyrin IX dimethyl ester derivatives and ext.ra planar pyridine Iigands may be correIated by a Hammett linear free-energy plot [7]_
We wish to report here the correlation of a variety of the physical properties of substituted deuteroporphyrin IX dimethyl ester derivatives