Zhou Zheng, Greenough Joshua, Wei Zheng, Petrukhina Marina A
Department of Chemistry, University at Albany, State University of New York, 1400 Washington Ave., New York 12222, USA.
Acta Crystallogr C Struct Chem. 2017 May 1;73(Pt 5):420-423. doi: 10.1107/S2053229617005678. Epub 2017 Apr 26.
Only a few cyclooctatetraene dianion (COT) π-complexes of lanthanides have been crystallographically characterized. This first single-crystal X-ray diffraction characterization of a scandium(III) COT chloride complex, namely di-μ-chlorido-bis[(η-cyclooctatetraene)(tetrahydrofuran-κO)scandium(III)], [Sc(CH)Cl(CHO)] or [Sc(COT)Cl(THF)] (THF is tetrahydrofuran), (1), reveals a dimeric molecular structure with symmetric chloride bridges [average Sc-Cl = 2.5972 (7) Å] and a η-bound COT ligand. The COT ring is planar, with an average C-C bond length of 1.399 (3) Å. The Sc-C bond lengths range from 2.417 (2) to 2.438 (2) Å [average 2.427 (2) Å]. Direct comparison of (1) with the known lanthanide (Ln) analogues (La, Ce, Pr, Nd, and Sm) illustrates the effect of metal-ion (M) size on molecular structure. Overall, the M-Cl, M-O, and M-C bond lengths in (1) are the shortest in the series. In addition, only one THF molecule completes the coordination environment of the small Sc ion, in contrast to the previously reported dinuclear Ln-COT-Cl complexes, which all have two bound THF molecules per metal atom.
只有少数镧系元素的环辛四烯二价阴离子(COT)π配合物得到了晶体学表征。钪(III)COT氯化物配合物,即二-μ-氯代-双[(η-环辛四烯)(四氢呋喃-κO)钪(III)],[Sc(CH)Cl(CHO)]或[Sc(COT)Cl(THF)](THF是四氢呋喃),(1),的首次单晶X射线衍射表征揭示了一种具有对称氯桥[平均Sc-Cl = 2.5972 (7) Å]和一个η配位的COT配体的二聚体分子结构。COT环是平面的,平均C-C键长为1.399 (3) Å。Sc-C键长范围为2.417 (2)至2.438 (2) Å[平均2.427 (2) Å]。将(1)与已知的镧系元素(Ln)类似物(La、Ce、Pr、Nd和Sm)进行直接比较,说明了金属离子(M)大小对分子结构的影响。总体而言,(1)中的M-Cl、M-O和M-C键长在该系列中是最短的。此外,与先前报道的双核Ln-COT-Cl配合物相比,只有一个THF分子完成了小Sc离子的配位环境,先前报道的配合物每个金属原子都有两个配位的THF分子。