Our report [1] of a series of octanuclear {Cr7M} rings is the first such report
of anti-ferromagnetically coupled cyclic molecules that have a non-diamagnetic
ground state. There has been considerable interest in such molecules for
applications as diverse as olefin polymerisation catalysis [2], magnetic cooling
[3], and quantum computing [4]. Quite recently we reported [5] the synthesis,
structure and preliminary magnetic studies of new heterometallic wheels, that
form a very large family of complexes with general formula {[NR2H2][M7M′F8(O
2CR′)16]}, where M3+ = Cr, Fe, V; M’2+ = Mn, Fe, Co, Ni, Zn, Cd, Mg; R a linear
alkyl-chain on the protonated secondary amine, (O2CR′)- various carboxylates.
We have also shown, in a system of heterometallic {CrnNi} rings (n = 7 or 8),
that we can chose between octa- and nona-nuclear wheels by using appropriate
secondary ammonium ions as templates [1, 6]. Here we show that using the
synthetic approach and the procedures reported earlier [1, 5-7], but by including
other templates in the reactions we can isolate new types of hetero-metallocyclic
compounds. If we use a tertiary amine, NEt(cy-C6H11)2, compound [HNEt(cy-
C6H11)2][Cr9NiF12(O2CCMe3)18] (1) can be crystallized (Fig. 1). Using NMe(cy-
C6H11)2 two decametallic wheels can be separated and crystallised, differing in
the number of Ni centres in the ring. The first is [HNMe(cy-C6H11)2][Cr9NiF12(O2C
CMe3)18] (2), while the second complex is [HNMe(cy-C6H11)2]2[Cr8Ni2F12(O2CCM
e3)18] (3); in 2 the protonated amine is localized in the wheel, while in 3 a second
protonated amine is found outside. If we use NHtBuisPr a nonametallic wheel [H
2NtBuisPr][Cr8CdF9(O2CCMe3)18] (4) was isolated for the Cd2+ and a decametallic
ring [H2NtBuisPr][Cr9NiF10(O2CCMe3)20] (5) for the Ni2+.

Looking at templates involving N-atoms in an unsaturated environment we
choose imidazole (Im) and its derivatives e.g.:
1-methylimidazole (MeIm), 1-butylimidazole (BuIm), 1-benzylimidazole
(BzIm), 2-methylimidazole (2-MeIm), 4-methylimidazole (4-MeIm), 1,2-
dimethylimidazole (1,2-diMeIm), 2,4-dimethylimidazole (2,4-diMeIm). These
templates also give rings containing eight, nine or ten metals, and either one or
two heterometals: [2-MeImH][Cr7NiF8(O2CCMe3)16] (6), [2,4-diMeImH][Cr7NiF8
(O2CCMe3)16] (7), [ImH]2[Cr6Ni2F8 (O2CCMe3)16] (8),[ImH]2[Cr8NiF11(O2CCMe3)17]
(9), [4-MeImH]2[Cr8NiF11(O2CCMe3)17] (10), [BzImH]2[Cr7Ni2F9(O2CCMe3)18] (11),
[MeImH]2[Cr8Ni2F12(O2CCMe3)18](12),[BuImH]2[Cr8Ni2F12(O2CCMe3)18] (13), [1,2-
DiMeImH]2 [Cr8Ni2F12(O2CCMe3)18] (14), [1,2-DiMeImH]2 [Cr8Ni2F10(O2CCMe3)20]
(15), but now the protonated imidazoles in all cases are found inside the
wheels.
Elemental analysis, MS and X-ray structure characterization confirm the
identity of all the compounds discussed here.
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Acknowledgements. This work was supported by the EPSRC (UK), the EC
programme “QuEMolNa” (MRTN-CT 2003-504880) and INTAS (03-51-4532).