Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
Dalton Trans. 2019 Apr 2;48(14):4514-4519. doi: 10.1039/c9dt00558g.
A new paramagnetic ligand, betaDTDA, and its coordination complex with Fe(hfac)2 are reported (betaDTDA = 4-(benzothiazol-2'-yl)-1,2,3,5-dithiadiazolyl; hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato-). The neutral radical betaDTDA is the first dithiadiazolyl ligand designed to include an electropositive sulphur moiety outside the thiazyl heterocycle, increasing the capacity for supramolecular, structure-directing electrostatic contacts and enabling new pathways for magnetic exchange. The Fe(hfac)2(betaDTDA) complex is composed of a hs-Fe(ii) center with the three bidentate ligands arranged about the ion in a distorted octahedral 6-coordinate environment. The magnetic properties of crystalline Fe(hfac)2(betaDTDA) are consistent with strong antiferromagnetic (AF) coupling between the metal and ligand moments, giving rise to a well-defined Stotal = 3/2 ground state that is the only thermally populated state below 40 K. Below 4 K, this complex exhibits slow relaxation of the magnetization detected by ac susceptibility measurements consistent with a single-molecule magnet (SMM) behaviour.
一种新的顺磁配体βDTDA 及其与 Fe(hfac)2 的配合物被报道（βDTDA = 4-（苯并噻唑-2-基）-1,2,3,5-二噻二唑基；hfac = 1,1,1,5,5,5-六氟乙酰丙酮酸根）。中性自由基βDTDA 是第一个设计为在噻唑杂环外包含正电性硫部分的二噻二唑配体，增加了超分子、结构导向静电接触的能力，并为磁交换开辟了新途径。Fe(hfac)2(βDTDA) 配合物由一个 hs-Fe(ii)中心组成，三个双齿配体在离子周围呈扭曲的八面体 6 配位环境排列。结晶态 Fe(hfac)2(βDTDA) 的磁性性质与金属和配体磁矩之间的强反铁磁（AF）耦合一致，导致明确的总自旋 S = 3/2 基态，这是 40 K 以下唯一热占据的态。在 4 K 以下，该配合物表现出通过交流磁化率测量检测到的磁化缓慢弛豫，与单分子磁体（SMM）行为一致。
