Homoleptic 2,2′-bi-pyridine metal-ates(-I) of iron and cobalt, one cocrystallized with an anthracene radical anion and the other with neutral anthracene

摘要

Homoleptic 2,2′-bi-pyridine (bipy) metalates of iron and cobalt have been synthesized directly from the corresponding homo-leptic anthracene metalates. In the iron structure, bis-[([2.2.2]cryptand)potassium(I)] tris-(2,2′-bi-pyridine)-fer-rate(-I) anthracene(-I), [K(C18H36N2O6)] 2[Fe(C10H8N2)3](C14H10), the asymmetric unit contains one potassium complex cation in a general position, the Fe center and one and a half bipy ligands of the ferrate complex on a crystallographic twofold axis that includes the Fe atom, and one half of an anthracene radical anion whose other half is generated by a crystallographic inversion center. The cations and anions are well separated and the geometry about the Fe center is essentially octa-hedral. In the cobalt structure, ([2.2.2]cryptand)potassium(I) bis-(2,2′-bi-pyridine) -cobaltate(-I) anthracene hemisolvate tetra-hydro-furan (THF) disolvate, [K(C18H36N2O6)][Co(C10H8N2)2]·0.5C14H10·2C4H8O, the asymmetric unit contains the cation, anion, and both cocrystallized THF solvent mol-ecules in general positions, and one half of a cocrystallized anthracene mol-ecule whose other half is generated by a crystallographic inversion center. The cation and anion are well separated and the ligand planes in the cobaltate anion are periplanar. Each anthracene mol-ecule is midway between and is oriented perpendicular to a pair of symmetry-related bipy ligands such that aromatic donor-acceptor inter-actions may play a role in the packing arrangement. The lengths of the bonds that connect the bipy rings support the assertion that the ligands are bipy radical anions in the iron structure. However, in the case of cobalt, these lengths are between the known ranges for a bipy radical anion and a bipy dianion, and therefore no conclusion can be made from the crystallography alone. One cocrystallized THF solvent mol-ecule in the cobalt structure was modeled as disordered over three positions with appropriate geometric and thermal restraints, which resulted in a refined component mass ratio of 0.412 (4):0.387 (3):0.201 (3).