Siderophore, II. Tetrazolylenolat‐ und Semicorrinat‐Anionen als Chelatliganden für Eisen(II)‐und Kupfer(II)‐Ionen: Vom Molekül zum Kollektiv. Siderophores, II1. – Tetrazolyl Enolate and Semicorrinate Anions as Chelate Ligands for Iron(II) and Copper(II) Ion: From Molecular to Collective Structures

Reaction of tetrazolyl enolate 2 (HL²) with Cu(II) acetate yields the 3D‐coordination polymer 4 ([CuL₂²]n). the structure of which is unequivocally established by single‐crystal X‐ray diffraction. The formation of 4 is understandable if 2 or its enolate is considered as tridentate chelate ligand and if an intermediate formation of the coordinatively unsaturated copper(II) building block 6 is assumed. The monomers 6 are bidentate coordinating by the two CN groups, which leads to linking of monomers and to coordinative saturation at the copper(II) center of 6 with formation of three‐dimensional 4. Semicorrin 8 (HL⁴), however, reacts with Fe(II) to give the exceptional mononuclear tetrahedral chelate complex 10 (X‐ray). EPR and Mössbauer spectra of 4 and 10 are discussed.