Chemistry of novel bridging-imminium-vinyl diiron complexes

Novel bridging iminium-vinyl diiron complexes 1, have been obtained by alkynes insertion into the metal-aminocarbyne carbon bond of the [Fe2{mu-CNMe(2,6Me2C6H3)}(mu-CO)(CO)(NCMe)(Cp)2]SO3CF3, 1. Compounds 1 are cationic and characterized by a bridging unsaturated ligand, which is potentially reactive towards nucleophyliles. Here we report on the reaction of 1 with NaBH4 which result in hydride addition at the bridging ligand. The site of addition depends upon the nature of the substituents (R, see scheme) at the N atom. With the more hindered substituent (2-6Me2C6H3) the addition occurs on the beta-carbon yielding 2. By contrast, in the case of the dimethyl imminium complexes, the hydride attack occurs on the alpha-carbon generating 3 (scheme). The X ray crystal structure of of both 2 and 3 have been determined (the structure of 2 is reported in figure).