微氧（O₂⁻）桥连血红素/非血红素双铁配合物的合成与光谱学：一氧化氮还原酶活性位点的模型

Synthesis and spectroscopy of micro-oxo (O(2)(-))-bridged heme/non-heme diiron complexes: models for the active site of nitric oxide reductase.

作者信息

Wasser Ian M, Martens Constantinus F, Verani Claudio N, Rentschler Eva, Huang Hong-Wei, Moënne-Loccoz Pierre, Zakharov Lev N, Rheingold Arnold L, Karlin Kenneth D

机构信息

Department of Chemistry, Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, USA.

出版信息

Inorg Chem. 2004 Jan 26;43(2):651-62. doi: 10.1021/ic0348143.

DOI:10.1021/ic0348143

PMID:14731027

Abstract

In this paper, we describe the synthesis and study of a series of heme/non-heme Fe-O-Fe' complexes supported by a porphyrin and the tripodal nitrogen ligand TMPA [TMPA = tris(2-pyridylmethyl)amine]. The complete synthesis of ((6)L)Fe-O-Fe(X) (1) (X = OMe(-) or Cl(-), 69:31 ratio), where (6)L is the dianion of 5-(o-O-[(N,N-bis(2-pyridylmethyl)-2-(6-methoxyl)pyridinemethanamine)phenyl]-10,15,20-tris(2,6-difluorophenyl)porphine, is reported. The crystal structure for 1.PF(6) reveals an intramolecular heme/non-heme diferric complex bridged by an Fe-O-Fe' moiety; 90 degree angle (Fe-O-Fe') = 166.7(3) degrees, and d(Fe.Fe') = 3.556 A. Crystal data for C(70)H(57)ClF(12)Fe(2)N(8)O(3)P (1.PF(6)): triclinic, Ponemacr;, a = 13.185(3) A, b = 14.590 (3) A, c = 16.885(4) A, alpha = 104.219(4) degrees, beta = 91.572(4) degrees, gamma = 107.907(4) degrees, V = 2977.3(11) A(3), Z = 2, T = 150(2) K. Complex 1 (where X = Cl(-)) is further characterized by UV-vis (lambda(max) = 328, 416 (Soret), 569 nm), (1)H NMR (delta 27-24 [TMPA -CH(2)-], 16.1 [pyrrole-H], 15.2-10.5 [PY-3H, PY-5H], 7.9-7.2 [m- and p-phenyl-H], 6.9-5.8 [PY-4H] ppm), resonance Raman (nu(as)(Fe-O-Fe') 844 cm(-)(1)), and Mössbauer (delta(Fe) = 0.47, 0.41 mm/s; deltaE(A) = 1.59, 0.55 mm/s; 80 K) spectroscopies, MALDI-TOF mass spectrometry (m/z 1202), and SQUID susceptometry (J = - 114.82 cm(-)(1), S = 0). We have also synthesized a series of 3-, 4-, and 5-methyl-substituted as well as selectively deuterated TMPA(Fe') complexes and condensed these with the hydroxo complex (F(8))FeOH or (F(8)-d(8))FeOH to yield "untethered" Fe-O-Fe' analogues. Along with selective deuteration of the methylene hydrogens in TMPA, complete (1)H NMR spectroscopic assignments for 1 have been accomplished. The magnetic properties of several of the untethered complexes and a comparison to those of 1 are also presented. Complex 1 and related species represent good structural and spectroscopic models for the heme/non-heme diiron active site in the enzyme nitric oxide reductase.

摘要

在本文中，我们描述了一系列由卟啉和三脚架型氮配体TMPA [TMPA = 三(2 - 吡啶甲基)胺] 支撑的血红素/非血红素Fe - O - Fe' 配合物的合成与研究。报道了((6)L)Fe - O - Fe(X) (1)（X = OMe⁻ 或Cl⁻，比例为69:31）的全合成，其中(6)L是5 - (o - O - [(N,N - 双(2 - 吡啶甲基)-2 - (6 - 甲氧基)吡啶甲胺)phenyl]-10,15,20 - 三(2,6 - 二氟苯基)卟啉的二价阴离子。1·PF₆的晶体结构揭示了一个由Fe - O - Fe' 部分桥连的分子内血红素/非血红素双铁配合物；90°角(Fe - O - Fe') = 166.7(3)°，d(Fe·Fe') = 3.556 Å。C₇₀H₅₇ClF₁₂Fe₂N₈O₃P (1·PF₆)的晶体数据：三斜晶系，P1̅；a = 13.185(3) Å，b = 14.590(3) Å，c = 16.885(4) Å，α = 104.219(4)°，β = 91.572(4)°，γ = 107.907(4)°，V = 2977.3(11) Å³，Z = 2，T = 150(2) K。配合物1（其中X = Cl⁻）通过紫外 - 可见光谱（λmax = 328、416（Soret）nm、569 nm）、¹H NMR（δ 27 - 24 [TMPA - CH₂ - ]，16.1 [吡咯 - H]，15.2 - 10.5 [PY - 3H，PY - 5H]，7.9 - 7.2 [间位和对位苯基 - H]，6.9 - 5.8 [PY - 4H] ppm）、共振拉曼光谱（νas(Fe - O - Fe') 844 cm⁻¹）、穆斯堡尔光谱（δ(Fe) = 0.47、0.41 mm/s；δE(A) = 1.59、0.55 mm/s；80 K）、基质辅助激光解吸电离飞行时间质谱（m/z 1202）和超导量子干涉仪磁学测量（J = - 114.82 cm⁻¹，S = 0）进行了进一步表征。我们还合成了一系列3 - 、4 - 和5 - 甲基取代以及选择性氘代的TMPA(Fe')配合物，并将它们与羟基配合物(F₈)FeOH或(F₈ - d₈)FeOH缩合，得到“非束缚”的Fe - O - Fe' 类似物。连同TMPA中亚甲基氢的选择性氘代，已完成了1的¹H NMR光谱的全归属。还给出了几种非束缚配合物的磁性性质以及与1的磁性性质的比较。配合物1及相关物种代表了一氧化氮还原酶中血红素/非血红素双铁活性位点的良好结构和光谱模型。