Radiolytic reduction of rhodium porphyrins. Chain reaction in alkaline 2-propanol

Journal Article · Thu Apr 20 04:00:00 EDT 1995 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100016a043· OSTI ID:45006

Grodkowski, J; Neta, P ^[1]; Hambright, P ^[2]

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1. National Inst. of Standards and Technology, Gaithersburg, MD (United States)
2. Howard Univ., Washington, DC (United States)

Rhodium(II) tetramesitylporphyrin (Rh{sup III}TMP) undergoes radiolytic reduction in deoxygenated alkaline alcohol solutions to produce a transient Rh{sup II}TMP and then a stable Rh{sup I}TMP. When the solvent was 2-PrOH and the KOH concentration was $$LS@0.02 mol L{sup -1}, the radiolytic yield of reduction was considerably higher than the total yield of reducing radicals, indicating a chain reaction. The chain propagation process is suggested to be a reaction of the intermediate Rh{sup II}TMP with the solvent and the base to yield Rh{sup I}TMP and an additional reducing radical, (CH{sub 3}){sub 2}CO{sup -}. No chain reaction was observed with $$LB@KOH$RB > 0.01 mol L{sup -1} or when the solvent was MeOH. With pyridine as an axial ligand, reduction occurs on the porphyrin ring to yield Rh{sup III}TMP{sup -}, which then yields the stable Rh{sup I}TMP. Further radiolytic reduction of Rh{sup I}TMP in 2-PrOH takes place at the porphyrin ring to yield the chlorin and more highly reduced products. 25 refs., 2 figs., 1 tab.

• Sponsoring Organization: USDOE
• OSTI ID: 45006
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 16 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ABSORPTION SPECTRA
CHAIN REACTIONS
CHEMICAL REACTION KINETICS
GAMMA RADIATION
ORGANOMETALLIC COMPOUNDS
PORPHYRINS
POTASSIUM HYDROXIDES
PROPANOLS
PYRIDINES
RADIOLYSIS
REACTION INTERMEDIATES
REDUCTION
RHODIUM COMPOUNDS
SOLVENTS