Brenner Natasha, Sperling Joseph M, Poe Todd N, Celis-Barros Cristian, Brittain Kristi, Villa Eric M, Albrecht-Schmitt Thomas E, Polinski Matthew J
Department of Chemistry and Biochemistry, Bloomsburg University of Pennsylvania, 400 East Second Street, Bloomsburg, Pennsylvania 17815, United States.
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States.
Inorg Chem. 2020 Jul 6;59(13):9384-9395. doi: 10.1021/acs.inorgchem.0c01254. Epub 2020 Jun 23.
The synthesis, structure, and solid-state UV-vis-NIR spectroscopy of four new f-element squarates, M(CO)(HO) (M = Eu, Am, Cf) and Sm(CO)(COOH)(HO)·0.5HO, four new cationic lanthanide squarate chlorides, [M(CO)(HO)]Cl·5HO (M = Eu, Dy, Ho Er), and two new actinide squarate oxalates, M(CO)(CO)(HO) (M = Am, Cf), are presented. All of the metal centers are trivalent. Single-crystal X-ray diffraction analysis reveals that M(CO)(HO) and Sm(CO)(COOH)(HO)·0.5HO have a two-dimensional sheet structure constructed from MO(HO) monocapped square-antiprismatic (coordination number (CN) = 9) metal centers and SmO(HO) square-antiprismatic (CN = 8) metal centers, respectively, whereas M(CO)(CO)(HO) have a three-dimensional (3D) structure constructed from MO(HO) monocapped square-antiprismatic (CN = 9) metal centers. Additionally, the cationic framework materials [M(CO)(HO)]Cl·5HO have a 3D structure constructed from two crystallographically unique MO(HO) square-antiprismatic (CN = 8) metal centers. In these structures, the squarate ligands bind to the metal centers with varying coordination modes and denticities. The results of this study provide another example of the nonparallel chemistry between the lanthanides and transplutonium elements. From the crystallographic data for the isotypic series M(CO)(HO) (M = La-Nd, Sm, Eu) and the linear regression fit to a plot of the unit cell volume as a function of the cube of the ionic radius, the nine-coordinate ionic radius of Cf was determined to be 1.127 ± 0.003 Å. Finally, computational analysis of the americium and californium complexes M(CO)(HO) and M(CO)(CO)(HO) reveals three important attributes: (i) the 5f orbitals are nonbonding in all cases, with the bonding differences occurring with the empty 6d orbitals; (ii) the Cf complexes exhibit more covalent character than their Am counterparts; and (iii) there is more covalent character in the squarate-oxalate complexes than in the squarate complexes.
本文介绍了四种新型f元素方酸化合物M(CO)(HO)（M = Eu、Am、Cf）和Sm(CO)(COOH)(HO)·0.5HO、四种新型阳离子镧系方酸氯化物[M(CO)(HO)]Cl·5HO（M = Eu、Dy、Ho、Er）以及两种新型锕系方草酸化合物M(CO)(CO)(HO)（M = Am、Cf）的合成、结构和固态紫外-可见-近红外光谱。所有金属中心均为三价。单晶X射线衍射分析表明，M(CO)(HO)和Sm(CO)(COOH)(HO)·0.5HO分别具有由MO(HO)单帽方反棱柱体（配位数(CN) = 9）金属中心和SmO(HO)方反棱柱体（CN = 8）金属中心构成的二维层状结构，而M(CO)(CO)(HO)具有由MO(HO)单帽方反棱柱体（CN = 9）金属中心构成的三维(3D)结构。此外，阳离子骨架材料[M(CO)(HO)]Cl·5HO具有由两个晶体学上独特的MO(HO)方反棱柱体（CN = 8）金属中心构成的3D结构。在这些结构中，方酸配体以不同的配位模式和齿数与金属中心结合。本研究结果提供了镧系元素和超钚元素之间非平行化学的另一个例子。根据同型系列M(CO)(HO)（M = La-Nd、Sm、Eu）的晶体学数据以及对晶胞体积与离子半径立方的函数关系图进行的线性回归拟合，确定Cf的九配位离子半径为1.127 ± 0.003 Å。最后，对镅和锎配合物M(CO)(HO)和M(CO)(CO)(HO)的计算分析揭示了三个重要特性：(i) 在所有情况下5f轨道均为非键轨道，键合差异发生在空的6d轨道上；(ii) Cf配合物比其对应的Am配合物表现出更多的共价特性；(iii) 方草酸配合物比方酸配合物具有更多的共价特性。
