Structural studies of formamidine compounds: From neutral to anionic and cationic species

N,N'-Di(p-tolylformamidine), HDTolF, reacts with an ether solution of methyl lithium to give Li-2(mu-DTolF)(2)(Et(2)O)(2) (I), while N,N'-diphenylformamidine, HDPhF, reacts with a THF solution of MeMgCl to give the bioctahedral molecule (DPhF)(THF)Mg(mu-THF)(mu-Cl)(2)Mg(THF)(DPhF) (II), in which one of the THF molecules is bonded to both Mg atoms. Crystal structures of I, II, as well as the neutral molecule HDTolF (III) and the salt [H(2)DTolF][BF4] (IV) are presented. The neutral molecule shows distinct amine and imine C-N distances, while the ionic species show identical C-N distances. Copyright (C) 1996 Elsevier Science Ltd