INSERTION REACTIONS OF ISOCYANIDES AND NITRILES INTO UNSUPPORTED IRON ARYL BONDS - THE SYNTHESIS OF A DIMERIC IRON(II) HOMOLEPTIC IMINOACYL COMPLEX

The reaction of the dimer Fe2Mes4 [Mes = 2,4,6-Me3C6H2] (1) with Bu(t)NC led to [Fe2{(eta2-C(Mes)-NBut)}2(mu-C(Mes)=NBut)2] (2), a thermally stable homoleptic dimeric iminoacyl derivative containing both a terminal and a bridging iminoacyl functionality. 2 has a very short Fe-Fe distance [2.366(2) angstrom] and a low magnetic moment [3.40 mu(B) per iron at 250 K]. A 2-fold insertion was observed in the reaction of 1 with PhCN to give dimer 3, [{(PhCN)(Mes)Fe}2{mu-N=CPhMes}2], in which the iron atoms are bridged at a distance of 2.860(2) angstrom from each other by two imino anions. Complex 3 has a magnetic moment of 2.82 mu(B) at 250 K, suggesting a strong magnetic coupling between the two iron atoms.