Structure and Magnetism of Dinuclear Copper(II) Metallacyclophanes with Oligoacenebis(oxamate) Bridging Ligands: Theoretical Predictions on Wirelike Magnetic Coupling

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• 作者：Emilio Pardo ; Rosa Carrasco ; Rafael Ruiz-Garcí ; a ; Miguel Julve ; Francesc Lloret ; M. Carmen Mu&ntilde ; oz ; Yves Journaux ; Eliseo Ruiz ; Joan Cano
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：January 16, 2008
• 年：2008
• 卷：130
• 期：2
• 页码：576 - 585
• 全文大小：376K
• 年卷期：v.130,no.2(January 16, 2008)
• ISSN：1520-5126

文摘

Self-assembly of the ligands N,N'-1,5-naphthalenebis(oxamate) (1,5-naba) and N,N'-2,6'-anthracenebis(oxamate) (2,6-anba) by Cu^II ions affords the two new dicopper(II) metallacyclophanes 2aand 3b, whereby the metal centers are connected by double naphthalene- and anthracenediamidate bridgeswith ,' and ,' substitution patterns, respectively. Despite the largely different intermetallic distances of8.3 Å (2a) and 12.3 Å (3b), magnetic susceptibility measurements show a moderately strong antiferromagnetic coupling with rather similar J values in the range from -20.5 to -20.7 (2a) and from -21.2 to-23.0 (3b) cm^-1 (H = -J S₁ · S₂; S₁ = S₂ = ¹/₂). Density functional theory calculations on the two seriesof dicopper(II) metallacyclophanes 1a-10a and 1b-10b with linear ,'- and ,'-disubstituted oligoacenediamidate bridges, respectively, confirm the better efficiency of the latter substitution pattern on long-rangemagnetic coupling. More importantly, they predict a unprecedented wirelike magnetic behavior for the longestmembers of the series with octacene through decacene spacers (J values up to +3.0 cm^-1 for intermetallicdistances reaching 28.8 Å).