Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstrasse 34/36, D-14195 Berlin, Germany.
Inorg Chem. 2022 May 23;61(20):7765-7779. doi: 10.1021/acs.inorgchem.2c00070. Epub 2022 May 12.
The first technetium complexes containing anionic alkynido ligands in an end-on coordination mode have been prepared by using the nonprotic, cationic precursor ,-[Tc(SMe)(CO)(PPh)]. This cation acts as a functional analogue of the highly reactive 16-electron metallo Lewis acid {Tc(CO)(PPh)} in reactions with alkynes, acetylides, and other organometallic reagents. Such reactions give a variety of organometallic technetium complexes in excellent yields and enable the preparation of [Tc(CH)(CO)(PPh)], [Tc(Ph)(CO)(PPh)], [Tc(Cp)(CO)(PPh)], [Tc(═CCHCHCHO)(CO)(PPh)], [Tc(═CCHCHCHCHO)(CO)(PPh)], [Tc(C≡C-H)(CO)(PPh)], [Tc(C≡C-Ph)(CO)(PPh)], [Tc(C≡C-Bu)(CO)(PPh)], [Tc(C≡C-Bu)(CO)(PPh)], [Tc(C≡C-SiMe)(CO)(PPh)], and [Tc{C≡C-CH(CF)}(CO)(PPh)]. The bonding situation in the alkynyl complexes is compared to that in corresponding alkyl- and arylnitrile and -isonitrile complexes. Tc(N≡C-Ph)(CO)(PPh), Tc(C≡N-Ph)(CO)(PPh), Tc(N≡C-Bu)(CO)(PPh), and Tc(C≡N-Bu)(CO)(PPh) were prepared in high yields by ligand exchange reactions starting from ,-Tc(OH)(CO)(PPh). The novel complexes were characterized by single-crystal X-ray diffraction and spectroscopic methods. In particular, Tc nuclear magnetic resonance spectroscopy proved to be an invaluable and sensitive tool for the characterization of the complexes. Density functional theory calculations strongly suggest similar bonding situations for the related alkynyl, nitrile, and isonitrile complexes of technetium.
首例含有端式配位模式的负离子炔基配体的锝配合物已通过使用非质子、阳离子前体,-[Tc(SMe)(CO)(PPh)]制备。该阳离子在与炔烃、炔基化物和其他有机金属试剂的反应中充当高反应性 16 电子金属路易斯酸 {Tc(CO)(PPh)}的功能类似物。此类反应以优异的产率得到各种有机金属锝配合物，并能制备 [Tc(CH)(CO)(PPh)]、[Tc(Ph)(CO)(PPh)]、[Tc(Cp)(CO)(PPh)]、[Tc(═CCHCHCHO)(CO)(PPh)]、[Tc(═CCHCHCHCHO)(CO)(PPh)]、[Tc(C≡C-H)(CO)(PPh)]、[Tc(C≡C-Ph)(CO)(PPh)]、[Tc(C≡C-Bu)(CO)(PPh)]、[Tc(C≡C-Bu)(CO)(PPh)]、[Tc(C≡C-SiMe)(CO)(PPh)]和 [Tc{C≡C-CH(CF)}(CO)(PPh)]。炔基配合物中的键合情况与相应的烷基腈和芳基腈配合物中的键合情况进行了比较。Tc(N≡C-Ph)(CO)(PPh)、Tc(C≡N-Ph)(CO)(PPh)、Tc(N≡C-Bu)(CO)(PPh)和 Tc(C≡N-Bu)(CO)(PPh)通过从,-Tc(OH)(CO)(PPh)开始的配体交换反应以高产率制备。新型配合物通过单晶 X 射线衍射和光谱方法进行了表征。特别是，锝核磁共振光谱被证明是表征配合物的一种非常有价值且灵敏的工具。密度泛函理论计算强烈表明，相关的锝炔基、腈和异腈配合物具有相似的键合情况。
