Spin Canting and Metamagnetism in 2D and 3D Cobalt(II) Coordination Networks with Alternating Double End-On and Double End-to-End Azido Bridges

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• 作者：Jaursup Boonmak ; Motohiro Nakano ; Narongsak Chaichit ; Chaveng Pakawatchai ; Sujittra Youngme
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：August 1, 2011
• 年：2011
• 卷：50
• 期：15
• 页码：7324-7333
• 全文大小：1086K
• 年卷期：v.50,no.15(August 1, 2011)
• ISSN：1520-510X

文摘

By employing an N,N鈥?/i>-ditopic spacer 2-aminopyrazine (ampyz), two-dimensional (2D) (1) and three-dimensional (3D) (2) azido-bridged cobalt(II) coordination networks with the identical formula [Co(N₃)₂(ampyz)]_n have been synthesized and characterized structurally and magnetically. Compound 1 was prepared by the layer diffusion method in ambient temperature and crystallized in the high symmetric space group Immm. The 2D square-grid structure of 1 contains the perfect symmetric linear of alternating double end-on (EO) and double end-to-end (EE) azido-bridged Co^II chains which are linked together by an ampyz spacer in trans-arrangement. The intralayer 蟺鈥撓€ stacking interactions among ampyz spacers additionally stabilize this layer. The adjacent 2D layers are assembled by the intermolecular hydrogen bonding between the NH₂ of the ampyz and the EE azido ligands building a 3D structure. Compound 2 was prepared by a hydrothermal technique and shows a 3D framework containing a zigzag chain of similarly alternating double EO and double EE azido-bridged Co^II center. In contrast, this chain is linked by two ampyz spacers in cis-fashion giving rise to a 3D structure. The magnetic investigation of 1 shows the coexistence of a big spin canting angle and metamagnetism having magnetic ordering at 10 K, whereas the magnetic behavior of 2 simply exhibits spin-canted antiferromagnetism below T_N of 16 K.