A family of fourteen soluble stable macrocyclic [Ni II3LnIII] heterometallic 3d–4f complexes†
A family of fourteen tetranuclear, 3d–4f heterometallic nickel(II)–lanthanide(III) complexes of the hexaimine macrocycle (LPr)6−, with general formula NiII3LnIII(LPr)(NO3)3·xsolvents (LnIII = LaIII, CeIII, PrIII, NdIII, SmIII, EuIII, GdIII, TbIII, DyIII, HoIII, ErIII, TmIII, YbIII or LuIII), were prepared in a one-pot synthesis using a 3 : 1 : 3 : 3 reaction of nickel(II) acetate, the appropriate lanthanide(III) nitrate, the dialdehyde 1,4-diformyl-2,3-dihydroxybenzene (H2LAld) and 1,3-diaminopropane. In addition, three tetranuclear heterometallic nickel(II)–lanthanide(III) complexes of H2LAld, with general formula NiII3LnIII(LAld)3(NO3)3·xsolvents, were deliberately prepared (LnIII = LaIII, DyIII or YbIII) as in effect they represent intermediates en route to the above macrocyclic complexes. Whilst single crystals of the macrocyclic complexes were not forthcoming, X-ray crystal structure determinations on NiII3LnIII(LAld)3(NO3)3·xsolvents (LnIII = DyIII or YbIII) confirmed that the large ten-coordinate lanthanide(III) ion is bound in the central O6 pocket while the smaller six-coordinate nickel(II) ions are bound in the outer O4 pockets. In all fourteen cases, addition of the diamine to this intermediate (all in one pot) gives the tetrametallic [3 + 3] macrocyclic product. The magnetic properties of all fourteen macrocyclic complexes were measured down to 1.8 K to check for Single-Molecule Magnet behaviour, but no slow dynamics of magnetisation was observed.
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