Structural, spectroscopic, and reactivity comparison of xanthene- and dibenzofuran-bridged cofacial bisporphyrins

被引：91

作者：

Chang, CJ ^{[1
]}

Baker, EA ^{[1
]}

Pistorio, BJ ^{[1
]}

Deng, YQ ^{[1
]}

Loh, ZH ^{[1
]}

Miller, SE ^{[1
]}

Carpenter, SD ^{[1
]}

Nocera, DG ^{[1
]}

机构：

[1] MIT, Dept Chem, Cambridge, MA 02139 USA

来源：

INORGANIC CHEMISTRY | 2002年 / 41卷 / 12期

关键词：

D O I：

10.1021/ic0111029

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

A comparison of the structure, spectroscopy, and oxygen atom-transfer reactivity of cofacial bisporphyrins anchored by xanthene (DPX) and dibenzofuran (DPD) pillars is presented. The synthesis and characterization of dicopper(II) and dinickel(II) complexes of DPD completes a homologous series of homobimetallic zinc(II), copper(II), and nickel(II) complexes for both cofacial platforms. X-ray crystallographic analysis of the parent free-base porphyrins H4DPX (1) and H4DPD (5) confirms the face-to-face arrangement of the two porphyrin macrocycles with a large available range of vertical pocket sizes: 1 (C80H92Cl2N8O), triclinic, space group P (1) over bar, a = 13.5167(12) Angstrom, b = 21.7008(18) Angstrom, c = 23.808(2) Angstrom, alpha = 80.116(2)degrees, beta = 76.832(2)degrees, gamma = 80.4070(10)degrees, Z = 4; 5 (C80H83N8O2), monoclinic, space group C2/c, a = 22.666(2) Angstrom, b = 13.6749(14) Angstrom, c = 42.084(4) Angstrom, p = 94.554(2)degrees, Z = 8. EPR spectroscopy of dicopper(II) derivatives Cu2DPX (3) and Cu2DPD (7) complements the crystallographic studies by probing intramolecular metal-metal arrangements in frozen solution. Exciton interactions between the porphyrin subunits in fluid solution are revealed by steady-state and time-resolved electronic absorption and emission spectroscopy. The resulting compilation of structural and spectroscopic data provides a benchmark for the use of these and related platforms for the activation of small-molecule substrates. A structure-function relation is developed for the photoinduced oxygen atom-transfer reactions of bisiron(III) mu-oxo derivatives of DPX and DPD. The efficiency of the photochemical process is markedly dependent (similar to10(4)-fold) on the vertical flexibility of cofacial architecture provided by the spacer.

引用

页码：3102 / 3109

页数：8

共 36 条

[1]

Armarego W.L. F., 1996, PURIFICATION LAB CHE, V4th

[2]

Chang C. J., 2001, ELECT TRANSFER CHE 2, V3, P409

[3] Electrocatalytic four-electron reduction of oxygen to water by a highly flexible cofacial cobalt bisporphyrin [J].