The Rule Rather than the Exception: Structural Flexibility of [Ni(cyclam)]2+-Based Cyano-Bridged Magnetic Networks

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• 作者：Beata Nowicka ; Mateusz Reczyński ; Maria Bałanda ; Magdalena Fitta ; Bartłomiej Gaweł ; Barbara Sieklucka
• 刊名：Crystal Growth & Design
• 出版年：2016
• 出版时间：August 3, 2016
• 年：2016
• 卷：16
• 期：8
• 页码：4736-4743
• 全文大小：408K
• 年卷期：0
• ISSN：1528-7505

文摘

Changes in structure and magnetic properties accompanying guest removal, inclusion, or exchange in two CN-bridged 2D networks of honeycomb topology: {[Ni(cyclam)]₃[Fe(CN)₆]₂}_n (1) and {[Ni(cyclam)]₃[Cr(CN)₆]₂}_n (2) (cyclam = 1,4,8,11-tetraazacyclotetradecane) were studied by PXRD and magnetic measurements. For each compound four pseudopolymorphic forms differing in structure and magnetic characteristics were identified: fully hydrated form stable in water, partly hydrated form stable in the air at ambient conditions, anhydrous form, and MeOH-modified form. All forms can be reversibly transformed into one another by several interconversion pathways, which fully correspond between Fe and Cr compounds. All forms of 1 and 2 are metamagnetic-like with varied T_c and critical field H_cr. For several forms, differently shaped magnetic hysteresis loops can be observed. For the partly hydrated and MeOH modified forms structure models are proposed on the basis of PXRD data. Correlations between structural features and magnetic properties are discussed.