Four Redox Isomers of a [3 × 3] Copper-Iron Heterometal Grid

Hiroki Sato; Tatsuya Onuki; Graham N Newton; Takuya Shiga; Hiroki Oshio

doi:10.1021/acs.inorgchem.3c02498

Four Redox Isomers of a [3 × 3] Copper-Iron Heterometal Grid

Inorg Chem. 2023 Nov 6;62(44):18003-18008. doi: 10.1021/acs.inorgchem.3c02498. Epub 2023 Oct 13.

Authors

Hiroki Sato¹, Tatsuya Onuki¹, Graham N Newton², Takuya Shiga¹, Hiroki Oshio^{1

3}

Affiliations

¹ Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8571, Japan.
² GSK Carbon Neutral Laboratories for Sustainable Chemistry, University of Nottingham, Jubilee Campus, Nottingham NG7 2TU, U.K.
³ State Key Laboratory of Fine Chemicals, Dalian University of Technology 2 Linggong Road, Dalian 116024, China.

PMID: 37828836
DOI: 10.1021/acs.inorgchem.3c02498

Abstract

A mixed-valence heterometallic nonanuclear [3 × 3] grid complex, [Cu^I₂Cu^II₆Fe^III(L)₆](BF₄)₅·MeOH·9H₂O (1; MeOH = methanol), was synthesized by a one-pot reaction of copper and iron ions with multidentate ligand 2,6-bis[5-(2-pyridinyl)-1H-pyrazol-3-yl]pyridine (H₂L). 1 showed five quasi-reversible one-electron redox processes centered at +0.74, +0.60, +0.39, +0.27, and -0.13 V versus SCE, assignable to four Cu^I/Cu^II processes and one Fe^II/Fe^III couple, respectively. The two-electron-oxidized species [Cu^II₈Fe^III(L)₆](PF₆)₇·4MeOH·7H₂O (1^2eOx), the two-electron-reduced species [Cu^I₄Cu^II₄Fe^III(L)₆](PF₆)₃·2H₂O (1^2eRed), and the three-electron-reduced species [Cu^I₄Cu^II₄Fe^II(L)₆](PF₆)₂·5MeOH·H₂O (1^3eRed) were isolated electrochemically. The four redox isomers were characterized by single-crystal X-ray analysis, SQUID magnetometry, and Mössbauer spectroscopy.