Self-assembly of the [Fe(DABP)(3)]SO(4) (DABP = 5,5'-diamino-2,2'-bipyridine) or [Fe(bipy)(3)]SO(4) (bipy = 2,2'-bipyridine) complex with a tripodal tris(3-pyridylurea) ligand (L) results in a layered structure that includes a sulfate anion in the cleft of one L molecule. The two compounds, [Fe(DABP)(3)][SO(4) L] x 10 H(2)O (2) and [Fe(bipy)(3)][SO(4) L] x 9 H(2)O (3), show very similar sheets formed by the anionic units [SO(4) L](2-) and cationic building blocks ([Fe(DABP)(3)](2+) or [Fe(bipy)(3)](2+)). However, there are different water clusters that link the adjacent layers in the two products, that is, water parallelograms and quasi "water cubes" in 2 versus single water molecules, water dimers, and hexamers in 3. The half-encapsulation of sulfate by a single L molecule contrasts with the previously reported full-encapsulation of the sulfate ion by two L molecules in [M(H(2)O)(6)][SO(4) L(2)] (1). This different anion encapsulation is traced to the hydrogen-acceptor properties of the pyridyl groups of L together with the hydrogen-bonding properties of the cation secondary coordination sphere for a solid-state packing optimization. In 1 the direct hydrogen bonding from the secondary coordination sphere of octahedral [M(H(2)O)(6)](2+) to L-pyridyl helps in the formation of an octahedral cation-anion coordination in the NaCl-type structure. In 2 and 3, crystal water instead of the cations has to satisfy the hydrogen-accepting demands of L. Consequently, a non-spherical and only partly water-surrounded half-encapsulated [SO(4) L](2-) anion allows for a closer approach of the [Fe(DABP)(3)](2+) or [Fe(bipy)(3)](2+) cations than the [SO(4) L(2)](2-) anion. Then, the similar cation and anion size in 2 and 3 with the Coulomb attraction confined to a two-dimensional plane leads to the formation of a hexagonal BN (or graphite) lattice. Competition experiments with different anions for compound 2 reveal that SO(4)(2-) can be selectively crystallized against NO(3)(-), OAc(-), or ClO(4)(-).

The reaction of a ditopic diiminopyridine ligand 2,6-bis (1-(2,6-diisopropyl-4-(pyridin-3-yl)phenylimino)ethyl)pyridine (L) with group 12 metal salts in various solvent systems afforded 12 metal-organic coordination complexes, including zero-dimensional (0D) metallomacrocycle, one-dimensional (1D) chain, and two-dimensional (2D) network structures:In these complexes, the semirigid ligand L exhibits four kinds of coordination modes [(syn, syn, syn), (syn, syn, anti), (anti, anti, syn), (anti, anti, anti)], leading to the formation of various supramolecular structures. Complex 1a is a tetranuclear metallomacrocycle. 1b contains 1D zigzag chains propagating along two different directions, which further pack into a noninterpenetrated three-dimensional (3D) framework by hydrogen-bonding interactions. Complexes 1c, 2, 3, 9, and 10 exhibit a 1D helical chain structure, while 4, 5, 6, and 7 are 1D looped-chain coordination polymers. Complex 8 displays an unprecedented pentanuclear Hg(II)-based 2D network with both HgCl 2 and Hg 2 Cl 2 bridges. It is noteworthy that 1a and 1b are supramolecular isomers formed in different solvent systems. The effects of the solvent, metal center, and anion on the different conformations adopted by the ligand and the structure of the products have been discussed. Additionally, the luminescent properties of the complexes have been investigated in the solid state, which display increased ligand-based fluorescence emission at room temperature.

No abstract