How far can proteins bend the FeCO unit? Distal polar and steric effects in heme proteins and models
作者:Gigi B. Ray、Xiao Yuan Li、James A. Ibers、Jonathan L. Sessler、Thomas G. Spiro
DOI:10.1021/ja00080a019
日期:1994.1
ResonanceRaman (RR) spectra are reported for structurally defined CO adducts of two sterically constrained Fe II porphyrins: PocPiv, in which three of the pivaloylamino pickets of «picketfence» porphyrin (5,10,15,20-tetrakis-[o(pivaloylamino)phenyljporphyrin) are attached to a benzene cap by single methylene groups, and C 2 -Cap, in which a benzene cap is attached by carboxylate links and a pair
共振拉曼 (RR) 光谱报告了两个空间受限的 Fe II 卟啉的结构定义的 CO 加合物:PocPiv,其中三个“栅栏”卟啉(5,10,15,20-tetrakis-[o(新戊酰氨基)苯基卟啉)通过单个亚甲基连接到苯帽上,而 C 2 -Cap,其中苯帽通过羧酸盐连接和一对亚甲基连接到 5,10,15,20 的四个羟基-四(邻羟基苯基)卟啉。尽管两种加合物的 X 射线晶体结构显示出非常相似的 FeCO 几何形状,涉及少量弯曲和倾斜,但它们的振动频率和 RR 增强模式却大不相同
Brewer, Cynthia T.; Brewer, Greg, Journal of the Chemical Society, Dalton Transactions
作者:Brewer, Cynthia T.、Brewer, Greg
DOI:——
日期:——
Structure of a carbon monoxide adduct of a "capped" porphyrin: Fe(C2-Cap)(CO)(1-methylimidazole)
作者:Kimoon Kim、James A. Ibers
DOI:10.1021/ja00016a023
日期:1991.7
The structure of Fe(C2-Cap)(CO)(1-Melm) has been determined by single-crystal X-ray diffraction methods. It consists of the packing of two crystallographically independent porphyrin molecules and solvate molecules. Both porphyrin molecules display the expected connectivity in which the benzene caps are slanted with respect to the mean porphyrin planes (dihedral angles of 15.5 and 11.5-degrees for molecules 1 and 2, respectively). The centroids of the cap atoms are 5.57 and 5.68 angstrom from the mean porphyrin planes. Since this distance is 3.96 angstrom in H-2(C2-Cap), the cap moves 1.6-1.7 angstrom further away from the porphyrin upon binding a CO ligand inside the cavity. The coordinated CO ligand is slightly but detectably distorted from linearity, being both bent and tilted off the axis normal to the porphyrin. The Fe-C-O bond angle and the off-axis displacements for the C and O atoms of CO are 173.1 (9)degrees, 0.17 angstrom, and 0.41 angstrom, respectively, for molecule 1, and 175.8 (8)degrees and 0.12 and 0.28 angstrom, respectively, for molecule 2. Crystallographic data: triclinic P1BAR, Z = 4, a = 18.022 (2) angstrom, b = 20.017 (1) angstrom, c = 20.691 (2) angstrom, alpha = 70.507 (7)degrees, beta = 76.232 (10)degrees, gamma = 82.549 (7)degrees at -150-degrees-C, 18 468 observations, 1740 variables, R(F) = 0.096 (F0(2) > 3-sigma(F0(2))).