Alemayehu Abraham B, Settineri Nicholas S, Lanza Arianna E, Ghosh Abhik
Department of Chemistry, University of Tromsø, N-9037 Tromsø, Norway.
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720-8229, United States.
Inorg Chem. 2024 Dec 30;63(52):24787-24796. doi: 10.1021/acs.inorgchem.4c04091. Epub 2024 Dec 16.
The high-temperature (∼180 °C) reaction between free-base -triarylcorroles and Re(CO), followed by exposure to PCl and thiols (or elemental sulfur), affords rhenium-sulfido (ReS) corroles in 67-76% yields. The use of shorter reaction times, lower temperatures (∼130 °C), and a dithiol (e.g., ethane-1,2-dithiol) also allows the isolation of rhenium-dithiolato corroles, presumptive intermediates on the path to ReS corroles. The ReS corroles exhibit high thermal stability and two reversible oxidations and reductions in their cyclic voltammograms, with redox potentials nearly identical to those observed for analogous ReO corroles. The electrochemical HOMO-LUMO gaps of the complexes, at 2.2 eV, are consistent with ligand-centered oxidation and reduction. The UV-vis spectra of ReS corroles, on the other hand, differ significantly from those of their ReO counterparts. Scalar-relativistic DFT calculations suggest that this difference reflects low-energy LUMO+2 and LUMO+3 levels, consisting of Re-S π-antibonding interactions; the ReO corroles, in contrast, exhibit a larger LUMO+1/LUMO+2 gap, as expected for a relatively classical Gouterman-type metalloporphyrin analogue. The high stability of ReS corroles is consistent with geochemists' view of rhenium as a moderately chalcophilic element (i.e., one that partitions into sulfide melts) as well as with a recent quantitative analysis of thiophilicity, which indicates that rhenium's oxophilicity and thiophilicity are essentially evenly balanced.
游离碱三芳基卟啉与Re(CO)在高温（约180°C）下反应，随后暴露于PCl和硫醇（或元素硫）中，以67 - 76%的产率得到铼硫代（ReS）卟啉。使用较短的反应时间、较低的温度（约130°C）和二硫醇（如乙烷-1,2-二硫醇）也能分离出铼二硫醇基卟啉，它们可能是生成ReS卟啉过程中的中间体。ReS卟啉具有高热稳定性，其循环伏安图中有两个可逆的氧化和还原过程，氧化还原电位与类似的ReO卟啉几乎相同。配合物的电化学HOMO - LUMO能隙为2.2 eV，与以配体为中心的氧化和还原一致。另一方面，ReS卟啉的紫外可见光谱与它们的ReO对应物有显著差异。标量相对论DFT计算表明，这种差异反映了由Re - S π反键相互作用组成的低能量LUMO + 2和LUMO + 3能级；相比之下，ReO卟啉表现出更大的LUMO + 1/LUMO + 2能隙，这与相对经典的Gouterman型金属卟啉类似物预期的情况一致。ReS卟啉的高稳定性与地球化学家将铼视为中等亲硫元素（即一种会分配到硫化物熔体中的元素）的观点一致，也与最近对亲硫性的定量分析一致，该分析表明铼亲氧性和亲硫性基本平衡。
