title: Zn and Fe complexes containing a redox active macrocyclic biquinazoline ligand.
abstract: A series of iron and zinc complexes has been synthesized, coordinated by the macrocyclic biquinazoline ligand, 2-4:6-8-bis(3,3,4,4-tetramethyldihydropyrrolo)-10-15-(2,2'-biquinazolino)-[15]-1,3,5,8,10,14-hexaene-1,3,7,9,11,14-N(6) (Mabiq). The Mabiq ligand consists of a bipyrimidine moiety and two dihydropyrrole units. The electronic structures of the metal-Mabiq complexes have been characterized using spectroscopic and density-functional theory (DFT) computational methods. The parent zinc complex exhibits a ligand-centered reduction to generate the metal-coordinated Mabiq radical dianion, establishing the redox non-innocence of this ligand. Iron-Mabiq complexes have been isolated in three oxidation states. This redox series includes low-spin ferric and low-spin ferrous species, as well as an intermediate-spin Fe(II) compound. In the latter complex, the iron ion is antiferromagnetically coupled to a Mabiq-centered pi-radical. The results demonstrate the rich redox chemistry and electronic properties of metal complexes coordinated by the Mabiq ligand.
authors.affiliation: Max Planck Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany.
authors.forename: Priyabrata
authors.initials: P
authors.lastname: Banerjee
authors.forename: Anna
authors.initials: A
authors.lastname: Company
authors.forename: Thomas
authors.initials: T
authors.lastname: Weyhermüller
authors.forename: Eckhard
authors.initials: E
authors.lastname: Bill
authors.forename: Corinna R
authors.initials: CR
authors.lastname: Hess
mesh_terms: D003198:Computer Simulation; D018360:Crystallography, X-Ray; D007501:Iron / Q000737:chemistry*; D008024:Ligands; D047028:Macrocyclic Compounds / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D011799:Quinazolines / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: C540840:2-4-6-8-bis(3,3,4,4-tetramethyldihydropyrrolo)-10-15-(2,2'-biquinazolino)-(15)-1,3,5,8,10,14-hexaene-1,3,7,9,11,14-N(6); D008024:Ligands; D047028:Macrocyclic Compounds; D009942:Organometallic Compounds; D011799:Quinazolines; D007501:Iron; D015032:Zinc