Reaction of (chlorocarbonyl)metallocenes of iron and cobalt with 1,4-diaminobutane:: Synthesis of a heterobimetallic ferrocene-cobaltocenium complex

The reactivity differences of the neutral and cationic metallocenes (chlorocarbonyl)ferrocene and the salt of (chlorocarbonyl)cobaltocenium, when reacted with 1,4-diaminobutane, is presented. This reaction-afforded the heterobimetallic complex [{eta (5)-C5H5}Co(eta (5)-C5H4}(CO)NH(CH2)(4)NH(CO){eta (5)-C5H4}Fe{eta (5)-C5H5}][PF6] (4) as the major product, as well as the homobimetallic [{eta (5)-C5H5}Co{eta (5)-C5H4}(CO)NH(CH2)(2)](2)[PF6](2) (5) and only traces of [{eta (5)-C5H5}Fe{eta (5)-C5H4}(CO)NH(CH2)(2)](2) (6), and constitutes a useful model approach for the synthesis of heteromultimetallic dendrimers. These compounds have been characterized by H-1 and C-13 NMR, IR spectroscopy, and fast atom bombardment mass spectrometry (FAB-MS) and elemental analyses. The molecular structure of compound 4 was ascertained by X-ray crystallography. The electrochemical behavior of 4 and 5 has been studied by cyclic voltammetry.