Synthesis, Characterization, and Laser Flash Photolysis Reactivity of a Carbonmonoxy Heme Complex
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- 作者：David W. Thompson ; Ryan M. Kretzer ; Estelle L. Lebeau ; Donald V. Scaltrito ; Reza A. Ghiladi ; Kin-Chung Lam ; Arnold L. Rheingold ; Kenneth D. Karlin ; and Gerald J. Meyer
- 刊名：Inorganic Chemistry
- 出版年：2003
- 出版时间：August 25, 2003
- 年：2003
- 卷：42
- 期：17
- 页码：5211 - 5218
- 全文大小：147K
- 年卷期：v.42,no.17(August 25, 2003)
- ISSN：1520-510X
文摘
We present here the synthesis, characterization, and flash photolysis study of [(F8TPP)FeII(CO)(THF)] (1) {F8TPP= tetrakis(2,6-difluorophenyl)porphyrinate(2-)}. Complex 1 crystallizes from THF/heptane solvent system as atris-THF solvate, [(F8TPP)FeII(CO)(THF)]·3THF (1·3THF), with ferrous ion in the porphyrin plane (C61H52F8FeN4O5;a = 11.7908(2) Å, b = 20.4453(2) Å, c = 39.9423(3), 
= 90
, 
= 90, 
= 90; orthorhombic, P212121, Z =8; Fe-N4(av) = 2.00 Å; N-Fe-N (all) = 90.0). This complex (as 1·THF) has also been characterized by 1H NMR{six-coordinate, low-spin heme; CD3CN, RT, 
8.82 (s, pyrrole-H, 8H), 7.89 (s, para-phenyl-H, 8H), 7.46 (s, meta-phenyl-H, 4H), 3.58 (s, THF, 8H), 1.73 (s, THF, 8H)}, 2H NMR (pyrrole-deuterated analogue) [(F8TPP-d8)FeII(CO)(THF)] {THF, RT, 8.78 ppm (s, pyrrole-D)}, 13C NMR (on 13CO-enriched adduct) {THF-d8, RT, 206.5 ppm;CD2Cl2, RT, 206.1 ppm}, UV-vis {THF, RT, 
max, 411 (Soret), 525 nm}, and IR {293 K, solution, 
CO 1979cm-1 (THF), 1976 cm-1 (acetone), 1982 cm-1 (CH3CN)} spectroscopies. In order to more fully understand theintricacies of solvent-ligand binding (as compared to CO rebinding to the photolyzed heme), we have also synthesizedthe bis-THF adduct [(F8TPP)FeII(THF)2]. Complex 2 also crystallizes from THF/heptane solvent system as a bis-THF solvate, [(F8TPP)FeII(THF)2]·2THF (2·2THF), with ferrous iron in the porphyrin plane (C60H52F8FeN4O4; a =21.3216(3) Å, b = 12.1191(2) Å, c = 21.0125(2) Å, = 90, = 105.3658(5), = 90; monoclinic, C2/c, Z= 4; Fe-N4(av) = 2.07 Å; N-Fe-N (all) = 90.0). Further characterization of 2 includes UV-vis {THF, max, 421(Soret), 542 nm} and 1H NMR {six-coordinate, high spin heme; THF-d8, RT, 56.7 (s, pyrrole-H, 8H), 8.38 (s,para-phenyl-H, 8H), 7.15 (s, meta-phenyl-H, 4H)} spectroscopies. Flash photolysis studies employing 1 were ableto resolve the CO rebinding kinetics in both THF and cyclohexane solvents. In CO saturated THF {[CO] ~ 5 mM}and at [1] 
5 
M, the conversion of [(F8TPP)FeII(THF)2] (produced after photolytic displacement of CO) to [(F8TPP)FeII(CO)(THF)] was monoexponential, with kobs = 1.6 (±0.2) × 104 s-1. Reduction in [CO] by vigorous Arpurging gave kobs 103 s-1 in cyclohexane. The study presented in this report lays the foundation for applyingfast-time scale studies based on CO flash photolysis to the more complicated heterobimetallic heme/Cu systems.
= 90, = 90, = 90; orthorhombic, P212121, Z =8; Fe-N4(av) = 2.00 Å; N-Fe-N (all) = 90.0). This complex (as 1·THF) has also been characterized by 1H NMR{six-coordinate, low-spin heme; CD3CN, RT, 8.82 (s, pyrrole-H, 8H), 7.89 (s, para-phenyl-H, 8H), 7.46 (s, meta-phenyl-H, 4H), 3.58 (s, THF, 8H), 1.73 (s, THF, 8H)}, 2H NMR (pyrrole-deuterated analogue) [(F8TPP-d8)FeII(CO)(THF)] {THF, RT, 8.78 ppm (s, pyrrole-D)}, 13C NMR (on 13CO-enriched adduct) {THF-d8, RT, 206.5 ppm;CD2Cl2, RT, 206.1 ppm}, UV-vis {THF, RT, max, 411 (Soret), 525 nm}, and IR {293 K, solution, CO 1979cm-1 (THF), 1976 cm-1 (acetone), 1982 cm-1 (CH3CN)} spectroscopies. In order to more fully understand theintricacies of solvent-ligand binding (as compared to CO rebinding to the photolyzed heme), we have also synthesizedthe bis-THF adduct [(F8TPP)FeII(THF)2]. Complex 2 also crystallizes from THF/heptane solvent system as a bis-THF solvate, [(F8TPP)FeII(THF)2]·2THF (2·2THF), with ferrous iron in the porphyrin plane (C60H52F8FeN4O4; a =21.3216(3) Å, b = 12.1191(2) Å, c = 21.0125(2) Å, = 90, = 105.3658(5), = 90; monoclinic, C2/c, Z= 4; Fe-N4(av) = 2.07 Å; N-Fe-N (all) = 90.0). Further characterization of 2 includes UV-vis {THF, max, 421(Soret), 542 nm} and 1H NMR {six-coordinate, high spin heme; THF-d8, RT, 56.7 (s, pyrrole-H, 8H), 8.38 (s,para-phenyl-H, 8H), 7.15 (s, meta-phenyl-H, 4H)} spectroscopies. Flash photolysis studies employing 1 were ableto resolve the CO rebinding kinetics in both THF and cyclohexane solvents. In CO saturated THF {[CO] ~ 5 mM}and at [1] 5 M, the conversion of [(F8TPP)FeII(THF)2] (produced after photolytic displacement of CO) to [(F8TPP)FeII(CO)(THF)] was monoexponential, with kobs = 1.6 (±0.2) × 104 s-1. Reduction in [CO] by vigorous Arpurging gave kobs 103 s-1 in cyclohexane. The study presented in this report lays the foundation for applyingfast-time scale studies based on CO flash photolysis to the more complicated heterobimetallic heme/Cu systems.