Data for paper: Targeted Synthesis of End-on Dinitrogen-bridged Lanthanide Metallocenes and their Reactivity as Divalent Synthons

Dataset for Targeted Synthesis of End-on Dinitrogen-bridged Lanthanide Metallocenes and their Reactivity as Divalent Synthons published in Journal of the American Chemical Society September 2023 Data files CIF and checkCIF files for all crystal structures. IR spectroscopy data for all compounds. Raman spectroscopy data for all compounds. UV/visible spectroscopy data for all compounds. Magnetic measurement data for all compounds. Article abstract High-yield syntheses of the lanthanide dinitrogen complexes [(Cp2tttM)2(μ-1,2-N2)] (1M, M = Gd, Tb, Dy; Cpttt = 1,2,4-C5tBu3H2), in which the [N2]2– ligands solely adopt the rare end-on or 1,2-bridging mode, are reported. The bulk of the tert-butyl substituents and the smaller radii of gadolinium, terbium, and dysprosium preclude formation of the side-on dinitrogen bonding mode on steric grounds. Elongation of the nitrogen-nitrogen bond relative to N2 is observed in 1M, and their Raman spectra show a major absorption consistent with N═N double bonds. Computational analysis of 1Gd identifies that the local symmetry of the metallocene units lifts the degeneracy of two 5dπ orbitals, leading to differing overlap with the π* orbitals of [N2]2–, a consequence of which is that the dinitrogen ligand occupies a singlet ground state. Magnetic measurements reveal antiferromagnetic exchange in 1M and single-molecule magnet (SMM) behavior in 1Dy. Ab initio calculations show that the magnetic easy axis in the ground doublets of 1Tb and 1Dy align with the {M–N═N–M} connectivity, in contrast to the usual scenario in dysprosium metallocene SMMs, where the axis passes through the cyclopentadienyl ligands. The [N2]2– ligands in 1M allow these compounds to be regarded as two-electron reducing agents, serving as synthons for divalent gadolinium, terbium, and dysprosium. Proof of principle for this concept is obtained in the reactions of 1M with 2,2′-bipyridyl (bipy) to give [Cp2tttM(κ2-bipy)] (2M, M = Gd, Tb, Dy), in which the lanthanide is ligated by a bipy radical anion, with strong metal–ligand direct exchange coupling.### 数据集说明 本数据集对应2023年9月发表于《美国化学会志》（Journal of the American Chemical Society）的《面向端基桥联二氮桥连镧系茂金属的靶向合成及其作为二价合成子的反应性》研究工作。 #### 配套数据文件 1. 所有晶体结构的CIF及checkCIF文件 2. 所有化合物的红外（IR）光谱数据 3. 所有化合物的拉曼（Raman）光谱数据 4. 所有化合物的紫外-可见（UV/visible）光谱数据 5. 所有化合物的磁学测量数据 #### 论文摘要 本工作报道了二氮桥连镧系配合物[(Cp₂ᵗᵗᵗM)₂(μ-1,2-N₂)]（1M，M=钆(Gd)、铽(Tb)、镝(Dy)；Cpᵗᵗᵗ=1,2,4-三叔丁基环戊二烯基，即1,2,4-C₅ᵗBu₃H₂）的高产率合成路线，其中[N₂]²⁻配体仅采用罕见的端基或1,2-桥联配位模式。叔丁基取代基的空间位阻与钆、铽、镝较小的离子半径，从位阻效应层面排除了侧桥联二氮成键模式的生成可能。1M配合物中观测到氮-氮键相较于游离N₂发生伸长，其拉曼光谱显示出与N=N双键一致的主要吸收峰。对1Gd的计算分析表明，茂金属单元的局域对称性打破了两个5dπ轨道的简并性，使其与[N₂]²⁻的π*轨道产生不同程度的重叠，这一效应导致二氮配体处于单重基态。磁学测量结果显示1M中存在反铁磁交换相互作用，而1Dy表现出单分子磁体（single-molecule magnet, SMM）行为。从头算（ab initio）计算表明，1Tb和1Dy的基态二重态中磁易轴与{M–N═N–M}连接方向一致，这与镧系茂金属单分子磁体中的常规情形截然不同——常规情形下磁易轴穿过环戊二烯配体。1M中的[N₂]²⁻配体可将这类配合物视为双电子还原剂，作为二价钆、铽、镝的合成子（synthon）。通过1M与2,2'-联吡啶（2,2′-bipyridyl, bipy）的反应验证了这一概念的可行性：反应生成[Cp₂ᵗᵗᵗM(κ²-bipy)]（2M，M=Gd、Tb、Dy），其中镧系金属与联吡啶自由基阴离子配位，并存在强的金属-配体直接交换耦合作用。