New pentachromoium metal string complexes [Cr5(μ5-L)4X2] (X = Cl−, L = dppzda2− (1), dpzpda2− (2); X = NCS−, L = dppzda2− (3), dpzpda2− (4)) were designed and synthesized through pyrazine-modulation of tripyridyldiamine ligand. X-Ray crystallographic studies revealed a linear metal chain structure consisting of two quadruple Cr–Cr bonds and a separated high spin Cr(II) at an end in crystallized form. A quintet ground state was observed for all pentachromium(II) molecules by magnetic study with g values of 2.04–2.18. While the electronic structure remained unchanged after the modification of ligands, electrochemistry showed a significant change in the molecular orbital energy levels of metal string molecules. Observation of the first oxidation peak of 1 at +0.57 V and of 2 at +0.73 V revealed that these complexes are quite resistant to oxidation. Single molecular conductance measurements showed that the complex exhibited good electronic conductance.
新型五铬金属串配合物 [Cr5(μ5-L)4X2] (X = Cl−, L = dppzda2− (1), dpzpda2− (2); X = NCS−, L = dppzda2− (3), dpzpda2− ( 4))是通过三吡啶二胺配体的吡嗪调节来设计和合成的。 X 射线晶体学研究揭示了线性金属链结构,由两个四重 Cr-Cr 键和末端结晶形式的分离的高自旋 Cr(II) 组成。通过磁性研究,g 值为 2.04–2.18,观察到所有五铬 (II) 分子的五重基态。虽然配体修饰后电子结构保持不变,但电化学显示金属串分子的分子轨道能级发生了显着变化。对 +0.57 V 处的 1 和 +0.73 V 处的 2 的第一个氧化峰的观察表明,这些配合物具有相当的抗氧化性。单分子电导测量表明该配合物表现出良好的电子电导。
One-, two- and three-dimensional Cu(<scp>ii</scp>) complexes built via new oligopyrazinediamine ligands: from antiferromagnetic to ferromagnetic coupling
作者:Rayyat H. Ismayilov、Wen-Zhen Wang、Gene-Hsiang Lee、Shie-Ming Peng
DOI:10.1039/b507485a
日期:——
Six new pyrazine-modulated N,N′-bis(α-pyridyl)-2,6-diaminopyridine ligands (PMN5) were synthesized and their complexes studied. Reaction of copper(II) with the ligand that contained one pyrazine ring in its terminal position led to formation of a one-dimensional zigzag complex whereas copper(II) reactions with ligands containing three pyrazine rings or one pyrazine ring in its middle position yielded
六个新 吡嗪调节的N,N'-双(α-吡啶基)-2,6-二氨基吡啶配体(PMN5)进行了合成并研究了它们的配合物。铜(II)与铜的反应。配体在末端位置含有一个吡嗪环的环导致形成一维之字形络合物,而铜(II)与配体在中间位置含有三个吡嗪环或一个吡嗪环的化合物可得到直的一维络合物。二维复合物是由配体在两个末端带有两个吡嗪环。当引入镍(II)时,从三个吡嗪调制的 配体。可变温度磁化率测量的研究表明,通过 σ和π途径,在以6.8–隔开的Cu(II)中心之间的直的一维复合物中,J值从-2到-3 cm -1的J值具有弱的反铁磁相互作用的优异的Heisenberg链。6.9Å。之字形一维复合物显示出非常差的磁耦合。尽管Cu-Cu距离为7.2,但二维化合物仍显示出显着的铁磁相互作用。讨论了铁磁耦合,并将其归因于桥面内和面外联动的异常协调模式吡嗪戒指。三维杂金属Cu(II)-Ni(II)化合物显示出弱的反铁磁
A magnetic and conductive study on a stable defective extended cobalt atom chain
A defective extended cobalt atom chain complex has been synthesized and the magnetism and conductance are studied. The formation and the electron transporting pathway of EMACs are investigated.