Reactions of dicobalt octa(isocyanide) with 2-bromoacetophenone

Article abstract of DOI:10.1016/0022-328X(94)05033-8

The reaction of Co2(XylNC)8 (Xyl = 2,6-Me2C6H3) with 2-bromoacetophenone gave 2,3-bis(2,6-xylyl)imino-5-phenyl-2,3-dihydrofuran (1a) and the cobalta-azacyclopentane derivative CoBr(PhCOCH)XylNC)6 (2a).Structures of 1a and 2a were determined by X-ray analyses; 1a is a furan derivative and 2a has a distorted octahedral structure containing a five-membered metallacyclic moiety formed by an multiple insertion of isocyanide into a Co-C bond.Similar treatment at reflux in the presence of xylyl isocyanide gave two kinds of octahedral compounds, 3a and 4a, having similarformula composition CoBr(PhCOCH)(XylNC)5; 3a was found by X-ray analysis to have a cobaltacycle structure, containing a tridentate ligand consisting of sigma carbon, carbene and O-coordination sites, and 4a was proposed to have a cobalta-azacyclobutane framework.Keywords: Cobalt; Isocyanide; Insertion; Oxidative addition