O-2 AND CO BINDING TO IRON(II) PORPHYRINS - A COMPARISON OF THE PICKET FENCE AND POCKET PORPHYRINS
O-2 AND CO BINDING TO IRON(II) PORPHYRINS - A COMPARISON OF THE PICKET FENCE AND POCKET PORPHYRINS
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DOI：
10.1021/ja00348a019
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发表时间：
1983-01-01
影响因子：
15
通讯作者：
GIBSON, QH
中科院分区：
文献类型：
--
作者：
COLLMAN, JP;BRAUMAN, JI;GIBSON, QH
报道了各种Fe（II）卟啉体系的动力学和平衡O2和CO结合行为。与尖桩栅栏配合物相比，无保护的铁（II）卟啉降低了配体亲和力和配体缔合率。这可以用溶剂化效应来解释，溶剂化效应稳定了无保护的Fe（II）卟啉中的配位形式。与类似的开腔尖桩栅栏配合物相比，中、小袋卟啉的五坐标Fe（II）配合物的CO亲和力明显降低。动力学数据表明，袋状配合物CO亲和力的降低主要反映在缔合率的降低上。相比之下，与尖桩栅栏类似物相比，口袋模型显示O2解离和缔合率均降低。因此，在整个口袋和尖桩栅栏复合体的系列中，氧的亲和力实际上是相同的。这些结果在远端空间相互作用方面进行了讨论。
Kinetic and equilibirum O2 and CO binding behavior for various Fe(II) porphyrin systems are reported. Compared to the picket fence complexes, unprotected Fe(II) porphyrins have both lowered ligand affinities and lowered ligand association rates. This is explained in terms of a solvation effect which stabilizes the coordinate form in the unprotected Fe(II) porphyrins. Five-coordinate Fe(II) complexes of the sterically encumbered medium and small pocket porphyrins show substantially reduced CO affinities as compared to the analogous open-cavity picket fence complexes. Kinetic data indicate that the lowered CO affinities in the pocket complexes are primarily reflected in decreased association rates. By contrast, the pocket models show both decreased O2 dissociation and association rates as compared to the picket fence analogs. As such, the O2 affinities are virtually identical throughout the series of pocket and picket fence complexes. These results are discussed in terms of distal-side steric interactions.