A 5,000-fold increase in the HAT reactivity of a nonheme FeIV=O complex simply by replacing two pyridines of the pentadentate N4Py ligand with pyrazoles

• 成果类型: Article
• 署名作者: Pal, Nabhendu; Xiong, Jin; Jahja, Mehmet; Mahri, Sami; Young Jr, Victor G.; Guo, Yisong; Swart, Marcel; Que Jr, Lawrence
• 署名单位: University of Minnesota System; University of Minnesota Twin Cities; Carnegie Mellon University; Universitat de Girona; Universitat de Girona; ICREA
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9682
• DOI: 10.1073/pnas.2414962122
• 发表日期: 2025-02-11
• 关键词: oxoiron(iv) complex

摘要

A pentadentate [N5] ligand (N2Py2Pz) based on the classic N4Py (N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine) framework has been synthesized by replacing the two pyridylmethyl arms with corresponding (N-methyl)pyrazolylmethyl units to form [N-bis(1-methyl-2-pyrazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L1). The oxidation of the iron(II) precursor (N2Py2Pz)Fe-II(OTf)(2) (1) with ((BuSO2)-Bu-t)C6H4IO at 298 K leads to the formation of the [Fe-IV(O)(N2Py2Pz)](2+) intermediate (2) with a near-IR band at 750 nm (epsilon(M) = 250 M(-1)cm(-1)) and a t(1/2) similar to 2 min at 298 K. The introduction of the less basic pyrazolylmethyl ligands in place of two pyridylmethyl units generates Fe-IV=O intermediate 2 that exhibits a cyclohexane oxidation rate of 0.29 s(-1) at 298 K, which is 5,000-fold faster than that observed for the classic Fe-IV(O)N4Py parent complex and 40,000-fold more reactive than the least reactive Fe-IV(O)N2Py2Q ' complex in this series (Py = pyridine, Q ' = isoquinoline) recently reported by Nordlander.