Infinite Copper(II) Coordination Architectures from a Resonative Aminotriazine-Derived Tripodal Ligand: Synthesis, Structures, and Magnetic Properties

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• 作者：Meng-Jung Tsai ; Jing-Yun Wu ; Ming-Hsi Chiang ; Cheng-Hao Huang ; Ming-Yu Kuo ; Long-Li Lai
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：November 19, 2012
• 年：2012
• 卷：51
• 期：22
• 页码：12360-12371
• 全文大小：608K
• 年卷期：v.51,no.22(November 19, 2012)
• ISSN：1520-510X

文摘

The ligand 2,4,6-tris(2-picolylamino)-1,3,5-triazine (o-H₃tpat) with essentially resonative structure and two copper(II)-based one-dimensional coordination chain structures, [Cu₃Cl₅(o-H₂tpat)(H₂O)]路MeOH路CH₂Cl₂ (1) and [Cu₂(o-H₂tpat)(H₂O)(MeOH)(NO₃)₂](NO₃)路3MeOH (2), with different structural patterns have been synthesized and characterized using single crystal X-ray diffraction analysis. For o-H₃tpat, two crystalline forms showing different solid-state structural features are obtained from MeOH/Et₂O (form I) and CH₂Cl₂/Et₂O (form II), respectively. The o-H₃tpat form I adopts an asymmetric-configured all-amino resonative tautomer with three cis鈥搕rans鈥搕rans-arranged pyridyl groups, whereas the o-H₃tpat form II adopts also an identical resonative structure but where two of the three pyridyl groups are in a cis-manner and the third one is nearly coplanar with the central aminotriazine core. On the other hand, the designed tripodal ligand in both Cu(II)-complexes serves as a monoanion, o-H₂tpat^{鈥?/sup>, which suits a propeller-configured all-imino resonative structure in 1 and a syn鈥?i>anti-configured amino鈥搃mino鈥搃mino resonative structure in 2. These observations significantly indicate that the o-H₃tpat ligand can self-adjust and interconvert its conformation via a possible structure transformation associated with proton-shift to adapt a change in the crystallization and self-assembly reaction systems. In the magnetic point of view, 1 is treated as repeated chains composed of infinite {Cu₆Cl₁₀} units wherein the hexanuclear unit is further decomposed to one {Cu(II)₄Cl₆} and two magnetically isolated {Cu(II)Cl₂} subunits. Antiferromagnetic interactions are found for the Cu₄ subunits (g = 2.33, 2J₁ = 鈭?.6 cm鈥?, 2J₂ = 鈭?.6 cm鈥?, 2J₃ = 鈭?.1 cm鈥?, and J₄ held to zero). For 2, it is considered as an infinite chain that composes of Cu₂ units antiferromagnetically coupled (g = 2.03, 2J₁ = 鈭?.2 cm鈥?). The small antiferromagnetic exchange constants in both 1 and 2 suggest that the unpaired spins do not effectively interact through the tripodal o-H₂tpat鈥?/sup> ligands.}