Coordination and Supramolecular Chemistry Laboratory, Institute of Physical Chemistry Ilie Murgulescu, Romanian Academy, Splaiul Independentei 202, 060021 Bucharest, Romania.
Inorg Chem. 2013 Feb 4;52(3):1525-37. doi: 10.1021/ic302278q. Epub 2013 Jan 18.
The synthesis, crystal structure, and magnetic properties of four new mixed 3d-4f complexes with formulas [{Fe(III)(phen)(CN)(4)}(4)Gd(2)(III)(bpym)(NO(3))(2)(H(2)O)(4)]·2CH(3)CN·2H(2)O}(n) (1), [{Fe(III)(phen)(CN)(4)}(4)Tb(2)(III)(bpym)(H(2)O)(8)]·(NO(3))(2)·2CH(3)CN}(n) (2), [{Fe(III)(phen)(CN)(4)}(4)Sm(III)(bpym)(NO(3))(2)(H(2)O)(5)]·2CH(3)CN}(n) (3), and {Fe(III)(phen)(CN)(4)}(2)Pr(2)(III)(bpym)()(NO(3))(4)(H(2)O)(2) (4) (phen = 1,10-phenanthroline and bpym = 2,2'-bipyrimidine) are discussed here. Compounds 1-3 are isomorphous and their structure consists of neutral ladder-like motifs where the rungs are made up by bpym-bridged dilanthanide(III) cations and the rods are defined by Fe(phen)(CN)(4) units adopting a bis-monodentate coordination mode through two of its four cyanide ligands. The electroneutrality in this family is achieved by either a chelating [at the Gd(III) (1) and Sm(III) (3)] or free [at the Tb(III) (2)] nitrate group and a peripheral Fe(phen)(CN)(4) entity, which act as a monodentate ligand across one of its four cyanide groups toward the rare-earth cation (1-3). Compound 4 exhibits a neutral two-dimensional structure where (μ-bpym)bis[diaquadi(nitrato-κ(2)-O,O')praseodymium(III)] fragments are interlinked through Fe(phen)(CN)(4) units adopting a tris-monodentate coordination mode across three of its four cyanide groups. Each iron(III) ion in 1-4 is six-coordinate with two nitrogen atoms from a chelating phen and four cyanide-carbon atoms building a somewhat distorted octahedral environment. The trivalent rare-earth cations are 9- (1-3) and 10-coordinate (4) having in common two nitrogen atoms from a bidentate bpym and three (1-3)/two (4) cyanide nitrogens, the coordination environment being completed by chelating nitrate (1, 3, 4) and water molecules (1-4). Magnetic susceptibility measurements in the 1.9-300 K temperature range show the occurrence of antiferromagnetic interactions in 1 through both the single cyanide- and the bis-bidentate bpym ligands. A weak ferromagnetic interaction is observed for 3 whereas very weak, if any, magnetic interactions would occur in 2 and 4, with the spin-orbit coupling of the low-spin iron(III) ion and the ligand field effects of the Tb(III) (2) and Pr(III) (4) masking their visualization.
本文讨论了四个新的混合 3d-4f 配合物[{Fe(III)(phen)(CN)(4)}(4)Gd(2)(III)(bpym)(NO(3))(2)(H(2)O)(4)]·2CH(3)CN·2H(2)O}(n) (1), [{Fe(III)(phen)(CN)(4)}(4)Tb(2)(III)(bpym)(H(2)O)(8)]·(NO(3))(2)·2CH(3)CN}(n) (2), [{Fe(III)(phen)(CN)(4)}(4)Sm(III)(bpym)(NO(3))(2)(H(2)O)(5)]·2CH(3)CN}(n) (3), 和 {Fe(III)(phen)(CN)(4)}(2)Pr(2)(III)(bpym)()(NO(3))(4)(H(2)O)(2) (4)（phen = 1,10-菲咯啉，bpym = 2,2'-联吡啶）的合成、晶体结构和磁性。配合物 1-3 是同构的，它们的结构由中性梯状基元组成，梯级由 bpym 桥联的镧系元素（III）阳离子组成，棒由通过两个氰化物配体采用双单齿配位模式的 [Fe(phen)(CN)(4)]单元定义。该系列的电中性是通过螯合[在 Gd(III)（1）和 Sm(III)（3）]或游离[在 Tb(III)（2）]硝酸根和外围[Fe(phen)(CN)(4)]实体来实现的，该实体作为单齿配体穿过其四个氰化物中的一个朝向稀土阳离子（1-3）。化合物 4 表现出中性二维结构，其中（μ-bpym）双[二水合（硝酰基-κ(2)-O,O'）镨（III）]片段通过[Fe(phen)(CN)(4)]单元相互连接，[Fe(phen)(CN)(4)]单元通过三个氰化物中的四个氰化物采用三单齿配位模式。1-4 中的每个铁（III）离子都是六配位的，两个氮原子来自螯合的 phen 和四个氰化物碳原子，形成略微扭曲的八面体环境。三价稀土阳离子为 9-（1-3）和 10 配位（4），共有两个来自双齿 bpym 的氮原子和三个（1-3）/两个（4）氰化物氮原子，配位环境由螯合的硝酸盐（1、3、4）和水分子（1-4）完成。在 1.9-300 K 的温度范围内进行的磁化率测量表明，1 中通过单个氰化物和双齿 bpym 配体发生反铁磁相互作用。3 中观察到弱铁磁相互作用，而 2 和 4 中几乎不会发生任何磁相互作用，低自旋铁（III）离子的自旋轨道耦合和 Tb(III)（2）和 Pr(III)（4）的配体场效应掩盖了它们的可视化。
