Synthesis and structures of β-dialdiminatoantimony(iii) halides and β-dialdiminium hexahalogenoantimoniates

Abstract

From SbCl3, SbBr3 or SbI3 and an equivalent portion of the -dialdiminatopotassium compound K[{N(C6H3Pri2-2,6)C(H)}2CPh] [[triple bond]K(L)] in Et2O there was obtained in good yield the crystalline yellow [SbCl2(L)].(0.5thf).(0.5Et2O) (1) and the bis(bromo) analogue 2, or the orange [{SbI(L)(mu-I)}2].(0.5Et2O) (3). Each of 1-3 was treated with the appropriate dihalogen (X2) in Et2O. Thus, whereas 1 or 2 furnished the corresponding -dialdiminium hexahalogenoantimoniate [Et2O...H(L)H...OEt2][SbX6] (4, X = Cl; 6, X = Br), the iodo compound 3 afforded the known pyrazolium salt [N(C6H3Pri2-2,6)C(H)C(Ph)C(H)N(C6H3Pri2-2,6)][I5]. It is suggested that the source of the additional 2HX, required to convert 1 or 2 with X2 in Et2O into 4 or 6, was derived from halogenation of the N-aryl groups of L. The formation of 4 or 6 was achieved by the alternative synthesis from equivalent portions of [H2(L)]X, SbX3 and X2 in diethyl ether. The X-ray structures of the isomorphous compounds 1 and 2 and 4 and 6, as well as of 3, are reported.