BIOLOGICALLY RELATED IRON-SULFUR CHEMISTRY

拟议研究的广泛目标是阐明 形成途径、结构、电子和反应性 性质，以及含金属的生理功能 铁硫蛋白和酶的配位部位。方法论是 用合成类比方法研究化合物的活性中心 金属生物分子，其中低分子量部位表示是 制备及其在小分子水平上的性能考察 细节。将开展以下工作：(1)环状化合物的合成 多硫醇配体，用于稳定某些核心结构和 氧化程度。[Fe-MS-n]z，(2)合成与表征 [Fe2S2]1和[Fe4S4]3簇，以确定详细结构 和电子离域性质；(3)合成和表征 三核簇合物[Fe3S4]1，O的主要意图是 提供蛋白质Fe3S4簇的结构证据并进行检验 团簇重组反应，(4)双立方烷簇合物的合成 用于评估分子内电子相互作用；(5) Fe4S4团簇的合成与表征 在一个配基位置官能化；(6)反应顺序的阐明 导致还原的铁氧还蛋白类似物的形成 [Fe4S4(SR)4]3-，(7)本征核心结构变化的定义 伴随着生物上普遍存在的[Fe4S4]2，1电子转移 反应；(8)发展了一个结构和功能模型 亚硫酸盐和亚硝酸盐还原酶的活性部位，包括检查 通过合成还原底物中间体，(9)合成和 含[Fe2S]3，4，5桥联单元的配合物的表征 与硫氰菊酯相似；(10)继续发展 金属硫酸盐化学，重点是几何和电子 [M(SR)4]1-，2-和[M2(SR)6]2-物种的结构和反应活性。

The broad objective of the proposed research is the elucidation of the pathways of formation, the structural, electronic, and reactivity properties, and the physiological functions of the metal-containing coordination sites of iron-sulfur proteins and enzymes. The methodology is that of the synthetic analogue approach to the active sites of metallobiomolecules, whereby low molecular weight site representations are prepared and their properties scrutinized at the small molecule level of detail. These problems will be undertaken: (1) synthesis of cyclic polythiol ligands designed to stabilize certain core structures and oxidation levels. [Fe-mS-n]z, (2) synthesis and characterization of [Fe2S2]1+ and [Fe4S4]3+ clusters in order to determine detailed structures and electron delocalization properties; (3) synthesis and characterization of the trinuclear clusters [Fe3S4]1+,O with the main intentions of providing a structure proof for protein Fe3S4 clusters and examining cluster reconstitution reactions, (4) synthesis of double-cubane clusters for the purpose of assessing intramolecular electronic interactions; (5) synthesis and characterization of Fe4S4 clusters specifically functionalized at one ligand site; (6) elucidation of the reaction sequence leading to the formation of the reduced ferredoxin analogues [Fe4S4(SR)4]3-, (7) definition of the intrinsic core structural change accompanying the biologically pervasive [Fe4S4]2+,1+ electron transfer reaction; (8) development of a structural and functional model of the active sites of sulfite and nitrite reductase, including examination of reduced substrate intermediates by synthesis, (9) synthesis and characterization of complexes containing the [Fe2S]3+,4+,5+ bridge unit similar to that in sulfidohemerythrin; (10) continued development of metal-thiolate chemistry, with emphasis on the geometrical and electronic structures and reactivities of [M(SR)4]1-,2- and [M2(SR)6]2- species.