Sørensen Mikkel A, Weihe Høgni, Vinum Morten G, Mortensen Jesper S, Doerrer Linda H, Bendix Jesper
Department of Chemistry , University of Copenhagen , Universitetsparken 5 , DK-2100 Copenhagen , Denmark . Email:
Department of Chemistry , Boston University , 590 Commonwealth Avenue , Boston , Massachusetts 02215 , USA.
Chem Sci. 2017 May 1;8(5):3566-3575. doi: 10.1039/c7sc00135e. Epub 2017 Feb 28.
Exploitation of HSAB preferences allows for high-yield, one-pot syntheses of lanthanide complexes chelated by two Pd or Pt metalloligands, [M(SAc)] (SAc = thioacetate, M = Pd, Pt). The resulting complexes with 8 oxygen donors surrounding the lanthanides can be isolated in crystallographically tetragonal environments as either [NEt] (space group: 4/) or [PPh] (space group: 4/) salts. In the case of M = Pt, the complete series of lanthanide complexes has been structurally characterized as the [NEt] salts (except for Ln = Pm), while the [PPh] salts have been structurally characterized for Ln = Gd-Er, Y. For M = Pd, selected lanthanide complexes have been structurally characterized as both salts. The only significant structural difference between salts of the two counter ions is the resulting twist angle connecting tetragonal prismatic and tetragonal anti-prismatic configurations, with the [PPh] salts approaching ideal symmetry very closely ( = 44.52-44.61°) while the [NEt] salts exhibit intermediate twist angles in the interval = 17.28-27.41°, the twist increasing as the complete 4f series is traversed. Static magnetic properties for the latter half of the lanthanide series are found to agree well in the high temperature limit with the expected Curie behavior. Perpendicular and parallel mode EPR spectroscopy on randomly oriented powder samples and single crystals of the Gd complexes with respectively Pd- and Pt-based metalloligands demonstrate the nature of the platinum metal to strongly affect the spectra. Consistent parametrization of all of the EPR spectra reveals the main difference to stem from a large difference in the magnitude of the leading axial term, 02, this being almost four times larger for the Pt-based complexes as compared to the Pd analogues, indicating a direct Pt(5d )-Ln interaction and an arguable coordination number of 10 rather than 8. The parametrization of the EPR spectra also confirms that off-diagonal operators are associated with non-zero parameters for the [NEt] salts, while only contributing minimally for the [PPh] salts in which lanthanide coordination approximates point group symmetry closely.
利用硬软酸碱（HSAB）偏好性可实现高产率的一锅法合成由两个钯或铂金属配体[M(SAc)]（SAc = 硫代乙酸酯，M = Pd、Pt）螯合的镧系配合物。所得的围绕镧系元素有8个氧供体的配合物可在晶体学四方环境中作为[NEt]（空间群：4/）或[PPh]（空间群：4/）盐分离出来。当M = Pt时，完整系列的镧系配合物已被表征为[NEt]盐（除了Ln = Pm），而[PPh]盐已对Ln = Gd - Er、Y进行了结构表征。当M = Pd时，选定的镧系配合物已被表征为两种盐。两种抗衡离子盐之间唯一显著的结构差异是连接四方棱柱和四方反棱柱构型的扭转角，[PPh]盐非常接近理想对称性（ = 44.52 - 44.61°），而[NEt]盐在 = 17.28 - 27.41°区间呈现中间扭转角，随着完整的4f系列的遍历扭转角增大。发现镧系系列后半部分的静态磁性质在高温极限下与预期的居里行为很好地吻合。分别对具有基于钯和铂的金属配体的钆配合物的随机取向粉末样品和单晶进行垂直和平行模式的电子顺磁共振（EPR）光谱表明，铂金属的性质强烈影响光谱。对所有EPR光谱进行一致的参数化表明，主要差异源于主导轴向项02大小的巨大差异，基于铂的配合物的该项几乎是基于钯的类似物的四倍，这表明存在直接的Pt(5d ) - Ln相互作用，并且配位原子数可论证为10而非8。EPR光谱的参数化还证实，对于[NEt]盐，非对角算符与非零参数相关，而对于[PPh]盐，其中镧系配位非常接近 点群对称性，其贡献最小。
