Complexes of metal(II) halides of the first transition series with N,N,N′,N′-tetramethylmethane-diamine, -ethane-1,2-diamine and -propane-1,3-diamine

Complexes of metal(II) halides of the first transition series with three diamines Me2N(CH2)nNMe2 have been studied. For n=1 (tmmn), only dinuclear species [{MX2(tmmn)}2] have been isolated, whereas for n=3 (tmpn) only tetrahedral mononuclear species [MX2(tmpn)] have been characterised. For n=2 (tmen), structures of both kinds have been prepared, and also of a third kind, octahedral trans-[MX2(tmen)2]. These different structures are often interconvertible. The structural types are rationalised in terms of the dimensions of the diamines rather than of the properties of the metal(II) ions.