Cobalt Cyclopentadienyl-Phosphine Dinitrogen Complexes 

Gao-Xiang Wang^#, Xuechao Yan^#, Jianhao Yin, Zhu-Bao Yin, Junnian Wei*, Zhenfeng Xi.

Chem. Eur. J. 2022. DOI: 10.1002/chem.202202803. (^#Authors contributed equally.)

    By applying the potassium salts of cyclopentadienyl-phosphine ligands LK to CoCl₂, the corresponding cobalt chlorides (1, LCo(II)Cl) were prepared. By reducing complexes 1 with KHBEt₃ under N₂ atmosphere, bridging end-on complexes, L Co(I)-N₂-Co(I)L (2a and 2b), were obtained successfully. ¹⁵N₂-labeled 2a-¹⁵N₂ was prepared under ¹⁵N₂/¹⁴N₂ exchange in THF solution. LCo(I)-N₂-Co(I)L complex 2a could react with P₄ molecules to release N₂ and generate a Co-P₄-Co moiety 4. Further reduction of complex 2b led to cleavage of a P-C bond in the cyclopentadienyl-phosphine ligand, while novel µ-PCy₂ bridged Co(0)-N₂ complex 5 was provided. DFT calculations were performed and confirmed the experimental observations.