Crowding out: ligand modifications and their structure directing effects on brucite-like {M(μ-OH)} (M = Co(ii), Ni(ii)) core growth within polymetallic cages.

Previous employment of the ligands 2-methoxy-6-[(methylimino)methyl]phenol (LH) and 2-methoxy-6-[(phenylimino)methyl]phenol (LH) has resulted in the self-assembly of pseudo metallocalix[6]arene complexes of general formulae: M(μ-OH)(L) (M = Ni(ii), x = 1, y = 2 (1) and Co(ii/iii), x = 2, y = 3 (2)). Extrapolating upon this work, we report the coordination chemistry of ligands 2-methoxy-6-{[(2-methoxyphenyl)imino]methyl}phenol (LH), 2-[(benzylimino)methyl]-6-methoxyphenol (LH), 2-[(benzylamino)methyl]-6-methoxyphenol (LH) and 2-[(benzylamino)methyl]-4-bromo-6-methoxyphenol (LH), whose structures are modifications of ligands LH. These ligands are employed in the synthesis and characterisation of the dimetallic complex Ni(ii)(L)(HO)·2HO·3MeOH (3); the monometallic complexes [Ni(ii)(L)] (4) and [Co(iii)(L)]·HO·MeOH (5a); and the tetranuclear pseudo metallocalix[4]arene complexes: (NO)⊂Co(ii)(μ-OH)(L)(HO)·HO (6), (NO)⊂Ni(ii)(μ-OH)(L)(HO)·HO (7) and [Ni(ii)(μ-OH)(L)(NO)]·MeCN (8). The tetrametallic 'butterfly' core topologies in 6-8 are discussed with respect to their structural and topological relationship with their heptanuclear [M] (M = Co(ii), Ni(ii)) pseudo metallocalix[6]arene ancestors (1 and 2).