Nayak Panisha, Singh Ajit Kumar, Nayak Manisha, Kar Subhajit, Sahu Kasturi, Meena Kiran, Topwal Dinesh, Indra Arindam, Kar Sanjib
School of Chemical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar - 752050, India.
Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400 094, India.
Dalton Trans. 2024 Sep 10;53(35):14922-14932. doi: 10.1039/d4dt01628a.
In this study, we present two fully characterized nickel tetrathiocyanocorroles, representing a novel class of 3d-metallocorroles. These nickel(II) ions form square planar complexes, exhibiting a d-electronic configuration. These anionic complexes are stabilized by the electron-withdrawing SCN groups on the bipyrrole unit of the corrole. The reduced aromaticity in these anionic nickel(II) corrole complexes is evidenced by single crystal X-ray diffraction (XRD) data and a markedly altered absorption profile, with stronger Q bands compared to Soret bands. Notably, the UV-Vis and electrochemical data exhibit significant differences from previously reported nickel(II) corrole radical cation and nickel(II) porphyrin complexes. While these electrochemical data bear a resemblance to those of the anionic nickel(II) corrole by Gross , the UV-Vis data show substantial distinctions. Additionally, we explore the utilization of nickel(II)-corrole@CC (where CC denotes carbon cloth) as an electrocatalyst for the oxygen evolution reaction (OER) in an alkaline medium. During electrochemical water oxidation, the molecular catalyst is partially converted to nickel (oxy)hydroxide, Ni(O)OH. The structure reveals the coexistence of the molecular complex and Ni(O)OH in the active catalyst, achieving a turnover frequency (TOF) of 3.32 × 10 s. The synergy between the homogeneous and heterogeneous phases improves the OER activity, providing more active sites and edge sites and enhancing interfacial charge transfer.
在本研究中，我们展示了两种完全表征的四硫氰基镍卟啉，它们代表了一类新型的3d-金属卟啉。这些镍（II）离子形成平面正方形配合物，呈现d电子构型。这些阴离子配合物通过卟啉联吡咯单元上的吸电子SCN基团得以稳定。单晶X射线衍射（XRD）数据和明显改变的吸收谱证明了这些阴离子镍（II）卟啉配合物中芳香性的降低，与Soret带相比，Q带更强。值得注意的是，紫外可见光谱和电化学数据与先前报道的镍（II）卟啉自由基阳离子和镍（II）卟啉配合物有显著差异。虽然这些电化学数据与格罗斯报道的阴离子镍（II）卟啉的数据有相似之处，但紫外可见光谱数据显示出实质性的区别。此外，我们探索了镍（II）-卟啉@CC（其中CC表示碳布）作为碱性介质中析氧反应（OER）的电催化剂的应用。在电化学水氧化过程中，分子催化剂部分转化为氢氧化镍（氧），Ni（O）OH。结构揭示了活性催化剂中分子配合物和Ni（O）OH的共存，实现了3.32×10 s的周转频率（TOF）。均相和异相之间的协同作用提高了OER活性，提供了更多的活性位点和边缘位点，并增强了界面电荷转移。
