Eine elektrochemische und strukturelle Studie an den Eisensilylamiden Fe[N(SiMe3)2]2 und Fe[N(SiMe3)2]3

The bis(trimethyl)silylamido complex Na(THF){Fe[N(SiMe3)2]3} and the disilane tBu3SiSitBu3 were obtained from the reaction of Fe[N(SiMe3)2]3 with the sodium silanide Na(THF)2[SitBu3] in a mixture of benzene and THF. Single crystals of Na(THF){Fe[N(SiMe3)2]3} suitable for X-ray diffraction were grown from the reaction solution at ambient temperature (orthorhombic, C2221, Z = 4). The solid-state structure features a contact-ion pair with two short N–Na contacts. The THF adducts {M(THF)2[N(SiMe3)2]2} reacted with 2,2′-bipyridine to give the corresponding complexes {M(2,2bipy)[N(SiMe3)2]2} (M = Mn, Fe). Their structures (M = Fe: orthorhombic, Pca21, Z = 8; M = Mn: orthorhombic, Pbca, Z = 8) feature monomeric units. The cyclic voltammogram of Fe[N(SiMe3)2]3 revealed a reversible redox transition with the potential of −0,523 V (E1/2), which was assigned to the Fe(III)[N(SiMe3)2]3→ Fe(II)[N(SiMe3)2]3 redox transition, whereas the compounds {Fe(THF)2[N(SiMe3)2]2} (Eox = −0,379 V) and {Fe(2,2bipy)[N(SiMe3)2]2} (Eox = −0,436 V) featured irreversible oxidation waves. The related manganese bis(trimethylsilyl)amido complexes {Mn(THF)2[N(SiMe3)2]2} (Eox = −0,458 V) and {Mn(2,2bipy)[N(SiMe3)2]2} (Eox = −0513 V) also underwent irreversibile electron transfer processes.