Radiolytic reduction of tetrapropylporphycene and its iron, cobalt, nickel, copper, and tin complexes
- Univ. of Notre Dame, IN (United States)
- National Inst. of Standards and Technology, Gaithersburg, MD (United States)
- Universitaet zu Koeln (Germany)
One-electron and multielectron reductions of 2,7,12,17-tetrapropylporphycene (H{sub 2}TPrPc) and its Fe, Co, Ni, Cu, and Sn complexes in 2-PrOH solutions have been studied by radiolytic techniques. Formation and decay of intermediates formed upon one-electron reduction have been followed by kinetic spectrophotometric pulse radiolysis, and the absorption spectra of stable reduction products have been recorded following {gamma}-radiolysis. H{sub 2}TPrPc and Sn{sup IV}TPrPc are reduced to the {pi}-radical anions and then to the dianions, which are stable in alkaline 2-PrOPH. In neutral or acidic solutions, the {pi}-radical anions undergo proton enhanced disproportionation and the dianions undergo protonation. With the transition metal complexes, redox reactions of Fe{sup III}/Fe{sup II} and Co{sup III}/Co{sup II} have been observed. The porphycenes of Fe{sup II}, Co{sup II}, Ni{sup II}, and Cu{sup II} are reduced in most cases to form the {pi}-radical anions, M{sup II}Pc{sup .-}. The exception is the case of the Co{sup II}Pc, which forms Co{sup II}Pc{sup .-} in alkaline 2-PrOH but yields a short-lived Co{sup I}Pc in neutral 2-PrOH. Cu{sup II}Pc{sup .-} has some Cu{sup I} character, resulting in rapid demetallation in acidic solutions. The radical anions M{sup II}Pc{sup .-} also undergo proton-enhanced disproportionation to yield M{sup II}PcH{sub 2}. 21 refs., 6 figs., 1 tab.
- OSTI ID:
- 226754
- Journal Information:
- Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 10 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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