77761-16-1Relevant academic research and scientific papers
A reinvestigation of silver porphyrin electrochemistry. Reactions of Ag(III), Ag(II), and Ag(I)
Kadish,Lin,Ding,Wu,Araullo
, p. 3236 - 3242 (2008/10/08)
The homogeneous and heterogeneous oxidation and reduction of silver porphyrins were investigated in nonaqueous media. Eleven complexes of ((p-X)TPP)Ag (where TPP = the dianion of tetraphenylporphyrin) were electrochemically investigated in CH2Cl2, Me2SO, and pyridine. Up to four reversible electrode reactions were observed for each complex. These corresponded to the formation of Ag(III), Ag(III) cation radicals, Ag(I), and Ag(I) anion radicals. No evidence of demetalation was observed on the spectroelectrochemical time scale, and reversibly generated spectra of the Ag(I) complexes were obtained. Surprisingly, these spectra resembled those of (TPP)Ag2. The oxidation of ((p-X)TPP)Ag by Ce(IV) and the reduction of ((p-X)TPP)Ag by N2H4 were also investigated. The former reaction generated [((p-X)TPP)AgIII]+ while the latter generated Ag0 and (TPP)H2. Rate constants were calculated for the chemical oxidation of Ag(II) to Ag(III) as well as the demetalation of Ag(II) or Ag(I) by N2H4. Correlations were made between these chemical rate constants and the sum of the substituent constants, 4σ, for ((p-X)TPP)Ag. Correlations were also made between the spectral and electrochemical properties of ((p-X)TPP)Ag. In addition, linear free energy relationships involving electrochemical data and electronic absorption spectra are reported.
