Psomas George, Bréfuel Nicolas, Dahan Françoise, Tuchagues Jean-Pierre
Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205 route de Narbonne, 31077 Toulouse Cedex 04, France.
Inorg Chem. 2004 Jul 26;43(15):4590-4. doi: 10.1021/ic049877f.
Anaerobic reaction of ferrous thiocyanate with the deprotonated form of the pentadentate dinucleating Schiff base 1,3-bis[(2-pyridylmethyl)imino]propan-2-ol (LH) yields the novel trinuclear [Fe3L2(NCS)4(H2O)] species 1. LH results from the bis-condensation of 2-acetyl-pyridine with 1,3-diaminopropan-2-ol and includes an N4O donor set. The X-ray crystal structure of 1 [C38H40N12O3S4Fe3, triclinic, space group P-1; a = 10.7730(10) angstroms, b = 12.2048(14) angstroms, c = 19.0559(19) angstroms, alpha = 76.908(12) degrees, beta = 89.106(12) degrees, gamma = 79.637(12) degrees, V = 2399.8(4) angstroms3] can be described either as a bent linear arrangement of ferrous centers pairwise bridged through the alkoxo oxygen atom of L- or as a triangular FeII3 core with an Fe2-SCN-Fe3 bridge as the longer side of the Fe1-Fe2-Fe3 triangle. The metric parameters characterizing the ligand environments of the three ferrous centers in 1 and its Mössbauer spectra show that this unprecedented trinuclear structure involves two high-spin (Fe2 and Fe3) and one spin-crossover (Fe1) FeII centers. The donor set to the spin-crossover center (Fe1) is unprecedented: two Npyridine, two Nimine, and two Oalkoxo. Weak antiferromagnetic interactions transmitted through the end-to-end NCS bridge and/or through the O1-Fe1-O2 bridge operate between Fe2 and Fe3.
亚铁硫氰酸盐与五齿双核席夫碱1,3 - 双[(2 - 吡啶甲基)亚氨基]丙 - 2 - 醇（LH）的去质子化形式发生厌氧反应，生成了新型的三核配合物[Fe3L2(NCS)4(H2O)]，即化合物1。LH是由2 - 乙酰吡啶与1,3 - 二氨基丙 - 2 - 醇经双缩合反应得到的，其配位原子为N4O。化合物1 [C38H40N12O3S4Fe3，三斜晶系，空间群P - 1；a = 10.7730(10)埃，b = 12.2048(14)埃，c = 19.0559(19)埃，α = 76.908(12)°，β = 89.106(12)°，γ = 79.637(12)°，V = 2399.8(4)埃³]的X射线晶体结构既可以描述为亚铁中心通过L的烷氧基氧原子成对桥连形成的折线形线性排列，也可以描述为以Fe2 - SCN - Fe3桥作为Fe1 - Fe2 - Fe3三角形较长边的三角形FeII3核。表征化合物1中三个亚铁中心配体环境及穆斯堡尔谱的度量参数表明，这种前所未有的三核结构涉及两个高自旋（Fe2和Fe3）和一个自旋交叉（Fe1）的FeII中心。自旋交叉中心（Fe1）的配位原子组合是前所未有的：两个吡啶氮、两个亚胺氮和两个烷氧基氧。通过端对端的NCS桥和/或通过O1 - Fe1 - O2桥传递的弱反铁磁相互作用在Fe2和Fe3之间起作用。
