Crowding out: ligand modifications and their structure directing effects on brucite-like {Mx(3-OH)y} (M = Co(ii), Ni(ii)) core growth within polymetallic cages

Previous employment of the ligands 2-methoxy-6-[(methylimino)methyl]phenol (L1H) and 2-methoxy-6-[(phenylimino)methyl]phenol (L2H) has resulted in the self-assembly of pseudo metallocalix[6]arene complexes of general formulae: [M-7((3)-OH)(6)(L-x)(6)](NO3)(y) (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 (L3H), 2-[(benzylimino)methyl]-6-methoxyphenol (L4H), 2-[(benzylamino)methyl]-6-methoxyphenol (L5H) and 2-[(benzylamino)methyl]-4-bromo-6-methoxyphenol (L6H), whose structures are modifications of ligands L1-2H. These ligands are employed in the synthesis and characterisation of the dimetallic complex [Ni(ii)(2)(L-3)(3)(H2O)](NO3)2H(2)O3MeOH (3); the monometallic complexes [Ni(ii)(L-4)(2)] (4) and [Co(iii)(L-4)(3)]H2OMeOH (5a); and the tetranuclear pseudo metallocalix[4]arene complexes: [(NO3)< subset of>Co(ii)(4)((3)-OH)(2)(L-5)(4)(H2O)(2)](NO3)H2O (6), [(NO3)< subset of>Ni(ii)(4)((3)-OH)(2)(L-5)(4)(H2O)(2)](NO3)H2O (7) and [Ni(ii)(4)((3)-OH)(2)(L-6)(4)(NO3)(2)]MeCN (8). The tetrametallic butterfly' core topologies in 6-8 are discussed with respect to their structural and topological relationship with their heptanuclear [M-7] (M = Co(ii), Ni(ii)) pseudo metallocalix[6]arene ancestors (1 and 2).