title: π-π Stacking and ferromagnetic coupling mechanism on a binuclear Cu(II) complex.
abstract: The ferromagnetic couplings were observed in an unpublished crystal that consists of binuclear copper(II) complexes, namely, [Cu(2)(μ(1,3)-SCN)(2)(PhenOH)(OCH(3))(2)(HOCH(3))(2)] (PhenOH = 2-hydroxy-1,10-phenanthroline), and in the binuclear complex Cu(ii) ion assumes a distorted octahedral geometry and thiocyanate anion functions as a μ(1,3)-SCN(-) equatorial-axial (EA) bridging ligand. The analysis for the crystal structure indicates that there are three types of magnetic coupling pathways, in which two pathways involve π-π stacking between the adjacent complexes and the third one is the μ(1,3)-SCN(-) bridged pathway. The fitting for the data of the variable-temperature magnetic susceptibilities shows that there is a ferromagnetic coupling between adjacent Cu(II) ions with J = 50.02 cm(-1). Theoretical calculations reveal that the two types of π-π stacking resulted in ferromagnetic couplings with J = 4.16 cm(-1) and J = 2.75 cm(-1), respectively, and the bridged thiocyanate anions pathway led to a weaker ferromagnetic interaction with J = 0.88 cm(-1). The theoretical calculations also indicate that the ferromagnetic coupling sign from the two types of π-π stacking does not accord with McConnell I spin-polarization mechanism. The analysis for the Wiberg bond indexes that originate from the π-π stacking atoms indicates that the Wiberg bond indexes are relevant to the associated magnetic coupling magnitude and the Wiberg bond index is one of the key factors that dominates the associated magnetic coupling magnitude.
authors.affiliation: Engineering Research Center of Pesticide and Medicine Intermediate Clean Production, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan, PR China.
authors.forename: Yan-Hui
authors.initials: YH
authors.lastname: Chi
authors.forename: Li
authors.initials: L
authors.lastname: Yu
authors.forename: Jing-Min
authors.initials: JM
authors.lastname: Shi
authors.forename: Yi-Quan
authors.initials: YQ
authors.lastname: Zhang
authors.forename: Tai-Qiu
authors.initials: TQ
authors.lastname: Hu
authors.forename: Gui-Qiu
authors.initials: GQ
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
authors.forename: Peng
authors.initials: P
authors.lastname: Cheng
mesh_terms: D003198:Computer Simulation; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D003300:Copper