title: A mixed-valent pentanuclear Cu(II)(4)Cu(I) compound containing a radical-anion ligand.
abstract: Reaction of 2,4-(2,2'-dipyridylamino)-6-(2-pyridylhydrazino)-1,3,5-triazine, abbreviated dppht (5), with copper(II) chloride in methanol yields a mixed-valent Cu(II)(4)Cu(I) compound (6), also involving the presence of a radical anion. The single-crystal structure determination for [Cu(5)(5(M))(5(MR))Cl(8)] (6) reveals that the original dppht ligand (5) has been monochlorinated at one of its pyridine rings and oxidized at its hydrazyl moiety, generating the ligand 2,4-(2,2'-dipyridylamino)-6-(2-(5-chloropyridyl)azo)-1,3,5-triazine (5(M)). Moreover, the molecular structure of 6 indicates that one of the two coordinated ligands 5(M) is in a radical-anion state, symbolized as 5(MR), characterized by a typical N-N bond length of about 1.33 A for a one-electron reduced azo group. The nature of this unique [Cu(II)(4)Cu(I)(radical)] assembly is corroborated by X-ray absorption spectroscopy, electron paramagnetic resonance, and magnetic susceptibility measurements. Density-functional theory calculations are consistent with the unprecedented structural features and support the spectroscopic data.
authors.affiliation: Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
authors.forename: Tiddo J
authors.initials: TJ
authors.lastname: Mooibroek
authors.forename: Guillem
authors.initials: G
authors.lastname: Aromí
authors.forename: Manuel
authors.initials: M
authors.lastname: Quesada
authors.forename: Olivier
authors.initials: O
authors.lastname: Roubeau
authors.forename: Patrick
authors.initials: P
authors.lastname: Gamez
authors.forename: Serena
authors.initials: S
authors.lastname: DeBeer George
authors.forename: Joris
authors.initials: J
authors.lastname: van Slageren
authors.forename: Shadi
authors.initials: S
authors.lastname: Yasin
authors.forename: Eliseo
authors.initials: E
authors.lastname: Ruiz
authors.forename: Jan
authors.initials: J
authors.lastname: Reedijk
mesh_terms: D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D008024:Ligands; D008280:Magnetics; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry; D014227:Triazines / Q000737:chemistry; D056928:X-Ray Absorption Spectroscopy
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D014227:Triazines; D003300:Copper