title: Iron(II) cage complexes of N-heterocyclic amide and bis(trimethylsilyl)amide ligands: synthesis, structure, and magnetic properties.
abstract: Metallation of hexahydropyrimidopyrimidine (hppH) by [Fe{N(SiMe(3))(2)}(2)] (1) produces the trimetallic iron(II) amide cage complex [{(Me(3)Si)(2)NFe}(2)(hpp)(4)Fe] (2), which contains three iron(II) centers, each of which resides in a distorted tetrahedral environment. An alternative, one-pot route that avoids use of the highly air-sensitive complex 1 is described for the synthesis of the iron(II)-lithium complex [{(Me(3)Si)(2)N}(2)Fe{Li(bta)}](2) (3) (where btaH = benzotriazole), in which both iron(II) centers reside in 3-coordinated pyramidal environments. The structure of 3 is also interpreted in terms of the ring laddering principle developed for alkali metal amides. Magnetic susceptibility measurements reveal that both compounds display very weak antiferromagnetic exchange between the iron(II) centers, and that the iron(II) centers in 2 and 3 possess large negative axial zero-field splittings.
authors.affiliation: School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Sulway
authors.forename: David
authors.initials: D
authors.lastname: Collison
authors.forename: Joseph J W
authors.initials: JJ
authors.lastname: McDouall
authors.forename: Floriana
authors.initials: F
authors.lastname: Tuna
authors.forename: Richard A
authors.initials: RA
authors.lastname: Layfield
mesh_terms: D000577:Amides / Q000737:chemistry*; D005296:Ferrous Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008024:Ligands; D008280:Magnetics; D008958:Models, Molecular; D015394:Molecular Structure; D011789:Quantum Theory
chemical_list: D000577:Amides; D005296:Ferrous Compounds; D006571:Heterocyclic Compounds; D008024:Ligands