Monomeric Homoleptic (2-Pyridylmethyl)(tert-butyldimethylsilyl)amido Complexes of the Divalent Metals Mg, Mn, Fe, Co, and Zn

The transamination reaction of M[N(SiMe3)(2)](2) with (2-pyridylmethyl)(tert-bLityldimethylsilyl)amine yields the corresponding homoleptic metal bis[(2-pyridylmethyl)(tert-butyldimethylsilyl)amides] of Mg (1), Mn (2), Fe (3), Co (4) and Zn (5). All these compounds crystallize from hexane isotypic in the space group C2/c. From toluene the zinc derivative precipitates as toluene solvate 5-toluene. The molecular structures of these compounds are very similar with large NMN angles to the amide nitrogen atoms with NMN values of 148 degrees (1) and 150 degrees (5) for the diamagnetic compounds and 156 degrees for the paramagnetic derivatives 2 and 3. The Co derivative 4 displays a rather small NCoN angle of 142 degrees. Different synthetic routes have been explored for compound 3 which is also available via the metallation reaction of bis(2,4,6-trimethyl- phenyl)iron with (2-pyridylmethyl)(tert-butyldimethylsilyl)amine and via the metathesis reaction of lithium (2-pyridylmethyl)(tertbutyldimethylsilyl)amide with [(thf)(2)FeCl2]. In course of the metathesis reaction, an equimolar amount of lithium (2-pyridylmethyl)(tert-butyldimethylsilyl)amide and [(thf)(2)FeCl2] yields heteroleptic (2-pyridylmethyl)(tert-butyidimethylsilyl)amido iron(II) chloride (6) which crystallizes as a centrosymmetric dimeric molecule. The oxidative C-C coupling reaction of 5 with Sn[N(SiMe3)(2)](2) leads to the formation of tin(II) 1,2-bis(2-pyridyl)-1,2-bis(tert-butyidimethylsilylamido)ethane, tin metal and Zn[N(SiMe3)(2)](2).