Bimetallic iron–iron and iron–zinc complexes of the redox-active ONO pincer ligand† †Electronic supplementary information (ESI) available: Complete experimental procedures and magnetic measurements and models. CCDC 1417565–1417567. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5sc03006d Click here for additional data file. Click here for additional data file.

Janice L. Wong, Robert F. Higgins, Indrani Bhowmick, David Xi Cao, Géza Szigethy, Joseph W. Ziller, Matthew P. Shores* and Alan F. Heyduk* A new bimetallic platform comprising a six-coordinate Fe(ONO)2 unit bound to an (ONO)M (M1⁄4 Fe, Zn) has been discovered ((ONO)H3 1⁄4 bis(3,5-di-tert-butyl-2-phenol)amine). Reaction of Fe(ONO)2 with either (ONO)Fe(py)3 or with (ONO )FeCl2 under reducing conditions led to the formation of the bimetallic complex Fe2(ONO)3, which includes unique fiveand six-coordinate iron centers. Similarly, the reaction of Fe(ONO)2 with the new synthon (ONO c)Zn(py)2 led to the formation of the heterobimetallic complex FeZn(ONO)3, with a six-coordinate iron center and a five-coordinate zinc center. Both bimetallic complexes were characterized by single-crystal X-ray diffraction studies, solid-state magnetic measurements, and multiple spectroscopic techniques. The magnetic data for FeZn(ONO)3 are consistent with a ground state S 1⁄4 3/2 spin system, generated from a high-spin iron(II) center that is antiferromagnetically coupled to a single (ONOc) radical ligand. In the case of Fe2(ONO)3, the magnetic data revealed a ground state S 1⁄4 7/2 spin system arising from the interactions of one high-spin iron(II) center, one high-spin iron(III) center, and two (ONOc) radical ligands.