A Phosphorus Supported Multisite Coordinating Tris Hydrazone P(S)[N(Me)NCHC₆H₄-<i>o</i>-OH]₃ as an Efficient Ligand for the Assembly of Trinuclear Metal Complexes: Synthesis, Structure, and Magnetism

A phosphorus supported multisite coordinating ligand P(S)[N(Me)NCHC6H4-o-OH]3 (2) was prepared by the condensation of the phosphorus tris hydrazide P(S)[N(Me)NH2]3 (1) with o-hydroxybenzaldehyde. The reaction of 2 with M(OAc)2·xH2O (M = Mn, Co, Ni, x = 4; M = Zn, x = 2) afforded neutral trinuclear complexes {P(S)[N(Me)NCHC6H4-o-O]3}2M3 [M = Mn (3), Co (4), Ni (5), and Zn (6)]. The X-ray crystal structures of compounds 2−6 have been determined. The structures of 3−6 reveal that the trinculear metal assemblies are nearly linear. The two terminal metal ions in a given assembly have an N3O3 ligand environment in a distorted octahedral geometry while the central metal ion has an O6 ligand environment also in a slightly distorted octahedral geometry. In all the complexes, ligand 2 coordinates to the metal ions through three imino nitrogens and three phenolate oxygens; the latter act as bridging ligands to connect the terminal and central metal ions. The compounds 2−6 also show intermolecular CH···SP contacts in the solid-state which lead to the formation of polymeric supramolecular architectures. The observed magnetic data for the (s = 5/2)3 L2(Mn(II))3 derivative, 3, show an antiferromagnetic nearest- and next-nearest-neighbor exchange (J = −4.0 K and J‘ = −0.15 K; using the spin Hamiltonian ĤHDvV = −2J(Ŝ1Ŝ2 + Ŝ2Ŝ3) − 2J‘Ŝ1Ŝ3). In contrast, the (s = 1)3 L2(Ni(II))3 derivative, 5, displays ferromagnetic nearest-neighbor and antiferromagnetic next-nearest-neighbor exchange interactions (J = 4.43 K and J‘ = −0.28 K; Ĥ = ĤHDvV+ Ŝ1DŜ1 + Ŝ2DŜ2+ Ŝ3DŜ3). The magnetic behavior of the L2(Co(II))3 derivative, 4, reveals only antiferromagnetic exchange analogous to 3 (J = −4.5, J‘ = −1.4; same Hamiltonian as for 3).多位点配位磷配体 P(S)[N(Me)N=CH-C6H4-o-OH]3 (2) 可经由三(甲基氨基)硫代磷酰肼 P(S)[N(Me)NH2]3 (1) 与邻羟基苯甲醛的缩合反应合成制得。将配体2与金属乙酸盐 M(OAc)2·xH2O（其中M=Mn、Co、Ni时x=4；M=Zn时x=2）反应，可得到中性三核配合物 {P(S)[N(Me)N=CH-C6H4-o-O]3}2M3 [M=Mn(3)、Co(4)、Ni(5)及Zn(6)]。已通过X射线晶体结构（X-ray crystal structures）解析确定了化合物2~6的晶体结构。配合物3~6的结构表明，其三核金属聚集体呈近似线性排布。每个聚集体中的两个端基金属离子均处于畸变八面体配位环境，配位原子组成为N3O3；而中心金属离子则处于略微畸变的八面体配位环境，配位原子组成为O6。在所有配合物中，配体2均通过三个亚胺氮原子与三个酚氧原子与金属离子配位，其中酚氧原子作为桥联配体连接端基与中心金属离子。化合物2~6在固态下还存在分子间C-H···S=P接触作用，进而形成聚合物型超分子组装体（supramolecular architectures）结构。针对自旋量子数s=5/2的Mn(II)三核衍生物3的磁学测试数据显示，其存在最近邻与次近邻反铁磁交换相互作用（采用自旋哈密顿量（spin Hamiltonian）ĤHDvV = −2J(Ŝ1Ŝ2 + Ŝ2Ŝ3) − 2J'Ŝ1Ŝ3，其中J=−4.0 K，J'=−0.15 K）。与之相反，自旋量子数s=1的Ni(II)三核衍生物5则表现出最近邻铁磁交换、次近邻反铁磁交换的相互作用（J=4.43 K，J'=−0.28 K；哈密顿量为Ĥ = ĤHDvV + Ŝ1DŜ1 + Ŝ2DŜ2 + Ŝ3DŜ3）。Co(II)三核衍生物4的磁学行为与3类似，仅表现出反铁磁交换相互作用（J=−4.5，J'=−1.4；采用与3相同的自旋哈密顿量）。