Handzlik Gabriela, Ligielli Irene, Nain Sakshi, Khurana Rishu, Ali Md Ehesan, Papangelis Evangelos, Papapanagis Charalampos, Bailly Corinne, Tsoureas Nikolaos, Danopoulou Marianna, Bethanis Costas, Braunstein Pierre, Pinkowicz Dawid, Krzystek Jurek, Kyritsis Panayotis, Danopoulos Andreas A
Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, Krakow, 30-387, Poland.
Laboratory of Inorganic Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, Athens, 15771, Greece.
Chemistry. 2025 Jul 11;31(39):e202500607. doi: 10.1002/chem.202500607. Epub 2025 Jun 24.
Three-coordinate, paramagnetic Cr complexes of type [Cr(amido)Bn(NHC)], NHC = N, N'-bis-(2,4,6-trimethylphenyl)-imidazol-2-ylidene (IMes); N, N'-bis-(2,6-di-isopropylphenyl)-imidazol(in)-2-ylidene, (S)IDiPP; N, N'-bis-(2,6-di-isopropylphenyl)-imidazol-4-ylidene, (aIDiPP); amido = N(SiMe), NH(DiPP); Bn = benzyl, n = 2, m = 0; n = 1, m = 1, were prepared by substitution or aminolysis and thermolysis methods from [Cr{N(SiMe)}(THF)] or [CrBn((S)IDiPP)], respectively. Depending on the nature of the NHC and the amido ligands, different geometries at Cr (ranging from distorted trigonal planar, to extended Y-, compressed Y-, and distorted T-shaped) and conformations, were observed. HFEPR spectroscopy was employed to accurately determine spin Hamiltonian parameters, consisting of zero-field splitting (axial D and rhombic E components) and g-values, of five S = 2 complexes exhibiting D and E/D in the range from -2.98 to -1.63 cm and 0.026 - 0.069, respectively. AC magnetometry established slow magnetization relaxation in three complexes, operating by Raman or combined Raman-Orbach processes. Ab initio calculations provided computed zfs values, in good agreement with those obtained by HFEPR. Magnetostructural comparisons are made within this three-coordinate Cr family, as well as with previously studied two- or four- coordinate Cr complexes.
[Cr(酰胺基)苄基(NHC)]类型的三配位顺磁性铬配合物，其中NHC = N, N'-双-(2,4,6-三甲基苯基)-咪唑-2-亚基(IMes)；N, N'-双-(2,6-二异丙基苯基)-咪唑(in)-2-亚基，(S)IDiPP；N, N'-双-(2,6-二异丙基苯基)-咪唑-4-亚基，(aIDiPP)；酰胺基 = N(SiMe)，NH(DiPP)；苄基 = 苄基，n = 2，m = 0；n = 1，m = 1，分别通过取代、氨解和热解方法由[Cr{N(SiMe)}(THF)]或[Cr苄基((S)IDiPP)]制备。根据NHC和酰胺基配体的性质，观察到铬的不同几何构型（从扭曲的三角平面到扩展的Y形、压缩的Y形和扭曲的T形）和构象。采用高频电子顺磁共振光谱准确测定了五个S = 2配合物的自旋哈密顿参数，包括零场分裂（轴向D和菱形E分量）和g值，其D和E/D范围分别为-2.98至-1.63 cm和0.026 - 0.069。交流磁测量确定了三个配合物中的慢磁化弛豫，其通过拉曼或拉曼-奥尔巴赫组合过程进行。从头算计算提供了计算的零场分裂值，与通过高频电子顺磁共振获得的值良好吻合。在这个三配位铬家族内部以及与先前研究的二配位或四配位铬配合物进行了磁结构比较。
