Curtis Clayton J, Habenšus Iva, Conradie Jeanet, Bardin Andrey A, Nannenga Brent L, Ghosh Abhik, Tomat Elisa
Department of Chemistry and Biochemistry, The University of Arizona, 1306 E. University Blvd., Tucson, Arizona 85721, United States.
Department of Chemistry, University of the Free State, Bloemfontein 9300, Republic of South Africa.
Inorg Chem. 2024 Sep 16;63(37):17188-17197. doi: 10.1021/acs.inorgchem.4c02903. Epub 2024 Aug 31.
The identification of ligands that stabilize Au(III) centers has led to the isolation of complexes for applications in catalysis, gold-based therapeutics, and functional materials. Herein, we report the coordination of gold by tripyrrin-1,14-dione, a linear tripyrrole with the scaffold of naturally occurring metabolites of porphyrin-based protein cofactors (e.g., heme). Tripyrrindione HTD2 binds Au(III) as a trianionic tridentate ligand to form square planar complex [Au(TD2)(HO)], which features an adventitious aqua ligand. Two reversible ligand-based oxidations of this complex allow access to the other known redox states of the tripyrrindione framework. Conversely, (spectro)electrochemical measurements and DFT analysis indicate that the reduction of the complex is likely metal-based. The chemical reduction of [Au(TD2)(HO)] leads to a reactive species that utilizes dichloromethane in the formation of a cyclometalated organo-Au(III) complex. Both the aqua and the organometallic Au(III) complexes were characterized in the solid state by microcrystal electron diffraction (MicroED) methods, which were critical for the analysis of the microcrystalline sample of the organo-gold species. Overall, this study illustrates the synthesis of Au(III) tripyrrindione as well as its redox profile and reactivity leading to gold alkylation chemistry.
能够稳定金（III）中心的配体的鉴定，促使人们分离出了用于催化、金基治疗和功能材料领域的配合物。在此，我们报道了三吡咯-1,14-二酮（一种具有卟啉基蛋白质辅因子天然代谢产物支架结构的线性三吡咯）与金的配位情况。三吡咯二酮HTD2作为三阴离子三齿配体与金（III）结合，形成平面正方形配合物[Au(TD2)(HO)]，该配合物具有一个偶然存在的水合配体。该配合物的两次基于配体的可逆氧化反应，使得我们能够获得三吡咯二酮骨架的其他已知氧化还原态。相反，（光谱）电化学测量和密度泛函理论（DFT）分析表明，该配合物的还原反应可能基于金属。[Au(TD2)(HO)]的化学还原产生了一种活性物种，该活性物种在形成环金属化有机金（III）配合物的过程中利用了二氯甲烷。水合金（III）配合物和有机金属金（III）配合物均通过微晶电子衍射（MicroED）方法进行了固态表征，这对于分析有机金物种的微晶样品至关重要。总体而言，本研究阐述了金（III）三吡咯二酮的合成及其氧化还原特征和导致金烷基化化学的反应活性。
