Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
Dalton Trans. 2011 Feb 14;40(6):1254-60. doi: 10.1039/c0dt00853b. Epub 2010 Dec 23.
By utilizing a flexible co-ligand 1,2-bis(2-pyridyl)ethylene (2,2'-bpe), two new azido-bridged cobalt(II) complexes with the formulae Co₃(N₃)₆(OH₂)₂(2,2'-bpe)₂(2,2'-bpe)(n) (1) and Co(N₃)₂(2,2'-bpe)₂ (2) have been synthesized and structurally characterized. Compound 1 shows an uncommon 1D chain comprised of double EO azido bridged five- and six-coordinated Co(II) geometries in a unique (-5-5-6-)(n) sequence of the coordination number. The 2,2'-bpe acts as a terminal co-ligand and an uncoordinated molecule in the crystal lattice. Moreover the adjacent 1D chain is assembled by C-Hπ interactions and the intermolecular hydrogen bonding between uncoordinated 2,2'-bpe and coordinated water molecules building a 2D layer. Whereas, compound 2 is a 2D coordination network containing the alternating double EO and double EE bridging modes of azides and ditopic 2,2'-bpe bridges. The magnetic investigation of 1 reveals dominant intra-chain ferromagnetic interactions, with the double EO azide-bridge and weak inter-chain antiferromagnetic interactions, with overall metamagnetic behaviour, having magnetic ordering at 6 K. The magnetic behaviour of 2 shows spin-canted antiferromagnetism below a T(N) of 12 K.
利用柔性共配体 1,2-双(2-吡啶基)乙烯(2,2'-bpe)，合成并结构表征了两个新的叠氮桥联钴(II)配合物，化学式为Co₃(N₃)₆(OH₂)₂(2,2'-bpe)₂(2,2'-bpe)(n) (1)和Co(N₃)₂(2,2'-bpe)₂ (2)。化合物 1 显示出一种不常见的一维链，由双 EO 叠氮桥联的五和六配位 Co(II)几何形状组成，在独特的(-5-5-6-)(n)配位数序列中。2,2'-bpe 在晶体晶格中作为末端共配体和未配位分子存在。此外，相邻的 1D 链通过 C-Hπ相互作用和未配位 2,2'-bpe 和配位水分子之间的分子间氢键组装成二维层。相比之下，化合物 2 是一个二维配位网络，包含交替的双 EO 和双 EE 叠氮桥联模式和双齿 2,2'-bpe 桥。1 的磁性研究表明存在主导的链内铁磁相互作用，双 EO 叠氮桥和弱的链间反铁磁相互作用，具有整体顺磁行为，在 6 K 时具有磁有序。2 的磁性表现出在 T(N)为 12 K 以下的自旋倾斜反铁磁性。
