Homoleptic 1-D iron selenolate complexes—synthesis, structure, magnetic and thermal behaviour of 1∞[Fe(SeR)2] (R = Ph, Mes)
作者:Andreas Eichhöfer、Gernot Buth、Francesco Dolci、Karin Fink、Richard. A. Mole、Paul T. Wood
DOI:10.1039/c1dt10089k
日期:——
The first examples of polymeric homoleptic iron chalcogenolato complexes 1â[Fe(SePh)2] and 1â[Fe(SeMes)2] (Ph = phenyl = C6H5, Mes = mesityl = C6H2-2,4,6-(CH3)3) have been both prepared by reaction of [Fe(N(SiMe3)2)2] with two equivalents of HSeR (R = Ph, Mes) while 1â[Fe(SePh)2] was found to be also easily accessible through reactions of either FeCl2, Fe(OOCCH3)2 or FeCl3 with PhSeSiMe3 in THF. In the crystal, the two compounds form one-dimensional chains with bridging selenolate ligands comprising distinctly different FeâSeâFe bridging angles, namely 71.15â72.57° in 1â[Fe(SePh)2] and 91.80° in 1â[Fe(SeMes)2]. Magnetic measurements supported by DFT calculations reveal that this geometrical change has a pronounced influence on the antiferromagnetic exchange interactions of the unpaired electrons along the chains in the two different compounds with a calculated magnetic exchange coupling constant of J = â137 cmâ1 in 1â[Fe(SePh)2] and J = â20 cmâ1 in 1â[Fe(SeMes)2]. In addition we were able to show that the ring molecule [Fe(SePh)2]12 which is a structural isomer of 1â[Fe(SePh)2] behaves magnetically similar to the latter one. Investigations by powder XRD reveal that the ring molecule is only a metastable intermediate which converts in THF completely to form 1â[Fe(SePh)2]. Thermal gravimetric analysis of 1â[Fe(SePh)2] under vacuum conditions shows that the compound is thermally labile and already starts to decompose above 30 °C in a two step process under cleavage of SePh2 to finally form at 250 °C tetragonal PbO-type FeSe. The reaction of 1â[Fe(SePh)2] with the Lewis base 1,10-phenanthroline yielded, depending on the conditions, the octahedral monomeric complexes [Fe(SePh)2(1,10-phen)2] and [Fe(1,10-phen)3][Fe(SePh)4].
首次合成了聚合型均配铁硫醇盐配合物的首例示例1⃣️[Fe(SePh)2]和1⃣️[Fe(SeMes)2](Ph =苯基 = C6H5,Mes = 茂基 = C6H2-2,4,6-(CH3)3)。通过[Fe(N(SiMe3)2)2]与两倍当量的HSeR(R = Ph,Mes)反应制备了这两种化合物,而1⃣️[Fe(SePh)2]还可以通过FeCl2、Fe(OOCCH3)2或FeCl3与PhSeSiMe3在THF中的反应轻松获得。在晶体中,这两种化合物形成一维链结构,链中的桥联硒醇配体具有明显不同的Fe-Se-Fe桥联角度,即1⃣️[Fe(SePh)2]中为71.15-72.57°,而在1⃣️[Fe(SeMes)2]中为91.80°。磁性测量支持的DFT计算揭示,这种几何变化对两种不同化合物中沿链的未成对电子的反铁磁交换相互作用有显著影响,计算得到的磁交换耦合常数J分别为-137 cm-1(1⃣️[Fe(SePh)2])和-20 cm-1(1⃣️[Fe(SeMes)2])。此外,我们能够证明环状分子[Fe(SePh)2]12(1⃣️[Fe(SePh)2]的结构异构体)在磁性上与后者类似。粉末XRD研究表明,环状分子仅是一个亚稳态中间体,在THF中完全转化为1⃣️[Fe(SePh)2]。在真空条件下对1⃣️[Fe(SePh)2]进行热重分析显示,该化合物热稳定性较差,高于30°C时开始在两步分解过程中分解SePh2,最终在250°C时形成四方晶系PbO型FeSe。1⃣️[Fe(SePh)2]与路易斯碱1,10-菲咯啉的反应,根据条件不同,得到了八面体单体配合物[Fe(SePh)2(1,10-phen)2]和[Fe(1,10-phen)3][Fe(SePh)4]。