Rearrangements of CN- functionalities promoted by cobalt(I): reactivity of cyclopentadienylbis(ethylene)cobalt(I) with dibenzophenone azine, benzophenone oxime, benzylidene(phenyl)amine and crystal structure determinations of the products

Abstract

The reaction of [Co(cp)(C₂H₄)₂](1) with various CN– organic functionalities was explored. The results are very different depending on the substituents at the imino group. Dibenzophenone azine, Ph₂CN–NCPh₂, oxidatively adds to (1) forming a diamagnetic binuclear cobalt(II) complex [{Co(cp)}₂(µ-Ph₂CN)₂](2)[Co–Co 2.335(1)Å]. The reaction of (1) with benzophenone oxime, Ph₂CNOH, led, via a preliminary oxidative addition of the O–H bond to the metal, to the formation of a non-symmetric binuclear cobalt(II) complex [{Co(cp)}₂(µ-Ph₂CN)-(µ-Ph₂CNO)](3)[Co–Co 2.426(l)Å]. Benzylidene(phenyl)amine, PhCHNPh, undergoes a sort of ortho-metallation reaction with (1), the resulting metallacycle functioning as a ligand for a second [Co(cp)] unit. The binuclear complex [{Co(cp)}₂(µ-PhNCH₂C₆H₄)][Co–Co 2.375(l)Å](4) is formed. Compounds (2)–(4) were characterized by single-crystal X-ray analysis: (2), space group Fdd2, a= 18.346(3), b= 39.348(7), c= 8.359(2)Å, Z= 8, R= 0.046 for 1463 independent observed reflections; (3), space group P2₁/_c, a= 10.009(1), b= 30.433(3), c= 10.344(l)Å, β= 1 08.93(l)°, Z= 4, R= 0.041 for 2 274 independent observed reflections; (4), space group P2₁/n, a= 9.674(1), b= 8.512(1), c= 22.741(3)Å, β= 95.90(l)°, Z= 4, R= 0.040 for 1 845 independent observed reflections.