Cobalt Cyclopentadienyl-Phosphine Dinitrogen Complexes.

By applying the potassium salts of cyclopentadienyl-phosphine ligands LK to CoCl 2 , the corresponding cobalt chlorides (1, LCo II Cl) were prepared. By reducing complexes 1 with KHBEt 3 under a N 2 atmosphere, bridging end-on complexes, LCo I -N 2 -Co I L (2 a and 2 b), were successfully obtained. 15 N 2 -labeled [ 15 N 2 ]-2 a was prepared under 15 N 2 / 14 N 2 exchange in THF solution. LCo I -N 2 -Co I L complex 2 a could react with P 4 molecules to release N 2 and generate a Co-P 4 -Co moiety 4. Further reduction of complex 2 b led to cleavage of a P-C bond in the cyclopentadienyl-phosphine ligand to provide novel μ-PCy 2 -bridged Co 0 -N 2 complex 5. DFT calculations confirmed the experimental observations.