Assessing the activity and stereoselectivity of heterobimetallic Zr/Co complexes catalyzed terminal alkyne dimerization: A DFT study

Abstract

Early/late heterobimetallic complexes are widely recognized as one of the most effective catalysts for activating coupling reactions. Herein, DFT calculations were used to investigate the specific mechanisms of terminal alkyne dimerization facilitated by two types of Zr/Co complexes: the bis (phosphinoamide) complex B and the mono (phosphinoamide) complex C. In addition, their reaction activities were compared with that of three ligand‐bridged Zr/Co complex A. The results show that the activated mechanisms of the three reactions are similar, all of them contain inner‐ and outer‐sphere mechanisms, and the inner one is the optimal process. Compared to A, the terminal alkyne dimerizations activated by B and C have the lower energy barriers and better selectivity for the E‐isomer; thus, the mono‐ and bis‐(phosphinoamide) Zr/Co complexes are expected to show better activity and selectivity than tris (phosphinoamide) complexes. The stereoselectivity of E‐, Z‐, and gem‐isomers is controlled by the reductive elimination process. The IRI analysis reveals that the selectivity for E‐ and Z‐isomers is influenced due to the notable repulsion and vdW interaction between the second alkyne and the MeNPMe2 ligand. Our work provides a theoretical basis for experimental applications and offers inspiration for the design of high selectivity heterobimetallic complexes.