Andrews Lester, Cho Han-Gook
Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA.
Department of Chemistry, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon, 22012, South Korea.
Angew Chem Int Ed Engl. 2020 Feb 3;59(6):2496-2504. doi: 10.1002/anie.201914153. Epub 2019 Dec 30.
Cyanogen diluted in argon was reacted with laser ablated Zn atoms to produce the NCZnCN and NCZnZnCN cyanides and higher energy isocyanides ZnNC, CNZnNC, and CNZnZnNC, which were isolated in excess argon at 4 K. These reaction products, identified from the matrix infrared spectra of their -CN and -NC chromophore ligand stretching modes, were confirmed by C and N isotopic substitution and comparison with frequencies calculated by the B3LYP and CCSD(T) methods using the all electron aug-cc-pVTZ basis sets. The cyanide and isocyanide products were increased markedly by mercury arc UV photolysis, which covers the zinc atomic absorption. The above electronic structure calculations that produce appropriate ligand frequencies for these dizinc products also provide their Zn-Zn bond lengths: CCSD(T) calculations find a short 2.367 Å Zn-Zn bond in the NCZnZnCN cyanide, a shorter 2.347 Å Zn-Zn bond in the 37.4 kJ mol higher energy isocyanide CNZnZnNC, and a longer 4.024 Å bond in the dizinc van der Waals dimer. Thus, the diatomic cyanide (-CN) and isocyanide (-NC) ligands are as capable of stabilizing the Zn-Zn bond as many much larger ligands based on their measured and our calculated Zn-Zn bond lengths. This is the first example of dizinc complexes stabilized by different ligand isomers. Additional weaker bands in this region can be assigned to the analogous trizinc molecules NCZnZnZnCN and CNZnZnZnNC.
在氩气中稀释的氰与激光烧蚀的锌原子反应，生成了氰化锌（NCZnCN）和二氰化锌（NCZnZnCN）以及能量更高的异氰化物ZnNC、CNZnNC和CNZnZnNC，这些产物在4K的过量氩气中被分离出来。通过其-CN和-NC发色团配体伸缩模式的基质红外光谱鉴定出这些反应产物，并通过碳和氮的同位素取代以及与使用全电子aug-cc-pVTZ基组的B3LYP和CCSD(T)方法计算的频率进行比较来确认。汞弧紫外光解显著增加了氰化物和异氰化物产物，汞弧紫外光解覆盖了锌原子吸收。上述为这些二锌产物产生合适配体频率的电子结构计算也提供了它们的Zn-Zn键长：CCSD(T)计算发现在氰化锌（NCZnZnCN）中Zn-Zn键短至2.367 Å，在能量高37.4 kJ·mol的异氰化物CNZnZnNC中Zn-Zn键更短，为2.347 Å，而在二锌范德华二聚体中键长为4.024 Å。因此，基于所测量的和我们计算的Zn-Zn键长，双原子氰（-CN）和异氰（-NC）配体与许多大得多的配体一样能够稳定Zn-Zn键。这是由不同配体异构体稳定的二锌配合物的首个例子。该区域中其他较弱的谱带可归属于类似的三锌分子NCZnZnZnCN和CNZnZnZnNC。
