Applications of manganocene in the synthesis of Mn(II) amide and imide cages

The reactions of manganocene, Cp2Mn (Cp = C5H5), with 2-aminopyrimidines give similar, octameric amido/imido cage complexes of general formulae [{CpMnNHR}{MnNR}]4[R = 4,6-Me2pm (1a), 4-MeO-6-Mepm (1b), 4,6-(MeO)2pm (1c); pm = pyrimidinyl]. The structures of these complexes can be visualised as being composed of central Mn4N4 imido cubane units that are coordinated at their peripheries by four [CpMnNHpm] monomers. In contrast, less acidic 2-aminopyridine (2-NH2py) and 8-aminoquinoline (8-NH2quin) are only singly deprotonated under similar conditions, giving the unusual hexanuclear amido complex [Cp2Mn3(NHpy)4]2(2) and the dimer [CpMn((mu) -8-HNquin)]2(3). N,Nʹ-Dibenzylethylenediamine [(BnNHCH2)2] only forms the simple adduct [((eta)^1-Cp)((eta)^5-Cp)Mn{(BnNHCH2)2}] (4)(Bn = CH2Ph) with Cp2Mn, in which no deprotonation of the organic acid has occurred. The X-ray structures of the new complexes 1b-c, 3 and 4 are reported (1a and 2 having been communicated previously).