Octa-coordinated alkaline earth metal–dinitrogen complexes M(N2)8 (M=Ca, Sr, Ba)

摘要

We report the isolation and spectroscopic identification of the eight-coordinated alkaline earth metal-dinitrogen complexes M(Nsub2/sub)sub8/sub (M=Ca, Sr, Ba) possessing cubic (Osubh/sub) symmetry in a low-temperature neon matrix. The analysis of the electronic structure reveals that the metal-Nsub2/sub bonds are mainly due to [M(dsubπ/sub)]→(Nsub2/sub)sub8/sub π backdonation, which explains the observed large red-shift in N-N stretching frequencies. The adducts M(Nsub2/sub)sub8/sub have a triplet (sup3/supAsub1g/sub) electronic ground state and exhibit typical bonding features of transition metal complexes obeying the 18-electron rule. We also report the isolation and bonding analysis of the charged dinitrogen complexes [M(Nsub2/sub)sub8/sub]sup+/sup (M=Ca, Sr).