Department of Chemistry, Nankai University, Tianjin, 300071, People's Republic of China.
Dalton Trans. 2011 Jan 28;40(4):805-19. doi: 10.1039/c0dt00516a. Epub 2010 Dec 13.
The structures, luminescent and magnetic properties of three series of coordination polymers with formulas-{[Fe(3)Ln(2)(L(1))(6)(H(2)O)(6)]·xH(2)O}(n) (Ln = Pr-Er; 1-9), {[Co(3)Ln(2)(L(1))(6)(H(2)O)(6)]·yH(2)O}(n) (Ln = Pr-Dy, Yb; 10-17) and {[Co(2)Ln(L(2))(HL(2))(2)(H(2)O)(7)]·zH(2)O}(n) (Ln = Eu-Yb; 18-25) (H(2)L(1) = pyridine-2,6-dicarboxylic acid, H(3)L(2) = 4-hydroxyl-pyridine-2,6-dicarboxylic acid) were systematically explored in this contribution. [Fe(II)(HS)-L(1)-Ln(III)] (1-9) and [Co(II)-L(1)-Ln(III)] (10-17) series are isostructural, and display 3D porous networks with 1D nanosized channels constructed by Fe/Co-OCO-Ln linkages. Furthermore, two types of "water" pipes are observed in 1D channels. [Co(II)-L(2)-Ln(III)] (18-25) series exhibit 2D open frameworks based on double-stranded helical motifs, which are further assembled into 3D porous structures by intermolecular hydrogen bonds between hydroxyl groups. The variety of the resulting structures is mainly due to the HO-substitution effect. These 3D coordination polymers show considerably high thermal stability, and do not decomposed until 400 °C. The high-spin Fe(II) ion in [Fe(II)(HS)-L(1)-Ln(III)] was confirmed by X-ray photoelectron spectroscopy, Mössbauer spectroscopy and magnetic studies. The luminescent spectra of coordination polymers associated with Sm(III), Eu(III), Tb(III) and Dy(III) were systematically investigated, and indicate that different d-metal ions in d-f systems may result in dissimilar luminescent properties. The magnetic properties of [Fe(II)(HS)-L(1)-Ln(III)] (3, 6, 7, 9, 13), [Co(II)-L(1)-Ln(III)] (15-17) and [Co(II)-L(2)-Ln(III)] (19-24) coordination polymers were also studied, and the χ(M)T values decrease with cooling. For the single ion behavior of Co(II) and Ln(III) ions, the magnetic coupling nature between Fe(II)(HS)/Co(II) and Ln(III) ions cannot be clearly depicted as antiferromagnetic coupling.
本文系统地研究了三个系列的配位聚合物，其化学式分别为-{[Fe(3)Ln(2)(L(1))(6)(H(2)O)(6)]·xH(2)O}(n) (Ln = Pr-Er; 1-9)、{[Co(3)Ln(2)(L(1))(6)(H(2)O)(6)]·yH(2)O}(n) (Ln = Pr-Dy, Yb; 10-17) 和 {[Co(2)Ln(L(2))(HL(2))(2)(H(2)O)(7)]·zH(2)O}(n) (Ln = Eu-Yb; 18-25) (H(2)L(1) = 吡啶-2,6-二甲酸，H(3)L(2) = 4-羟基吡啶-2,6-二甲酸)。[Fe(II)(HS)-L(1)-Ln(III)] (1-9) 和 [Co(II)-L(1)-Ln(III)] (10-17) 系列是同构的，它们通过 Fe/Co-OCO-Ln 键连接形成具有一维纳米尺寸通道的 3D 多孔网络。此外，在一维通道中观察到两种类型的“水管”。[Co(II)-L(2)-Ln(III)] (18-25) 系列基于双链螺旋基元呈现 2D 开放框架，这些基元通过羟基之间的分子间氢键进一步组装成 3D 多孔结构。形成的结构的多样性主要归因于 HO-取代效应。这些 3D 配位聚合物具有相当高的热稳定性，直到 400°C 才分解。X 射线光电子能谱、穆斯堡尔谱和磁性研究证实了 [Fe(II)(HS)-L(1)-Ln(III)] 中高自旋 Fe(II)离子的存在。配位聚合物与 Sm(III)、Eu(III)、Tb(III)和 Dy(III)的发光光谱进行了系统研究，表明 d-f 体系中的不同 d 金属离子可能导致不同的发光性质。还研究了 [Fe(II)(HS)-L(1)-Ln(III)] (3、6、7、9、13)、[Co(II)-L(1)-Ln(III)] (15-17) 和 [Co(II)-L(2)-Ln(III)] (19-24) 配位聚合物的磁性，χ(M)T 值随冷却而降低。对于 Co(II)和 Ln(III)离子的单离子行为，Fe(II)(HS)/Co(II)和 Ln(III)离子之间的磁耦合性质不能明确描述为反铁磁耦合。
