A Three-Coordinate Cobalt(-I) Dinitrogen Complex

Le résumé fourni par la source

While most reported Co(-I) complexes are coordinatively saturated, we report herein a 16e – Co(-I) complex [(cyIDep)Co(η 2 -vtms)(N 2 )Na(OEt 2 )] 2 (where cyIDep = 1,3-di(2′,6′-diethylphenyl)-4,5-(CH 2 ) 4 -imidazol-2-ylidene; and vtms = vinyltrimethylsilane). The Co(-I) complex is isolated from the reaction of [(cyIDep)Co(η 2 -vtms) 2 ] with sodium under a dinitrogen atmosphere. It features short Co–N (1.695(3)/1.695(3) Å) and long N–N bonds (1.166(4)/1.168(3) Å). Theoretical study indicates the presence of 2-fold Co-to-N 2 π-backdonation interactions in the three-coordinate Co(-I) species, which might lead to thermodynamic gains to the unusual alkene-to-N 2 ligand exchange reaction that gives the Co(-I) complex. The attempts to functionalize the dinitrogen ligand in the Co(-I) complex with Me 3 SiCl and a N -heterocyclic silylene lead to the isolation of the cobalt(I) alkyl complex [(cyIDep)Co(C(SiMe 3 ) 2 Me)] and the cobalt(0) complex [( t -Bu NHSi)(cyIDep)Co(η 2 -vtms)] ( t -Bu NHSi = 1,3-bis( tert -butyl)-1,3-diaza-2-silacyclopent-4-en-2-ylidene), respectively, rather than the desired products.

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