Self-Assembly of Diboronic Esters with U-Shaped Bipyridines: "Plug-in-Socket" Assemblies

Self-assembled complexes utilizing the ditopic dative bond acceptor 1,3-diboronic acid with catechol and complementary U-shaped donors in the form of 1,8-dipyridylnaphthalenes (1,8-bis(4-pyridyl)naphthalene (DPN), 1,8-bis(4-ethylenylpyridyl)naphthalene (DEPN), and 1,8-bis(4-ethynylpyridyl)naphthalene (DAPN)) yielded discrete two-component structures. The assemblies exhibit "plug-in-socket" geometries. DFT calculations are consistent with the donor pyridyl and acceptor catecholate being electron poor and rich, respectively. The assemblies pack via π-π interactions and support the inclusion of a solvent (i.e., DPN, DAPN). The materials may form a basis for the design of complex B-based structures (e.g., supramolecular dyads).

Simultaneous encapsulation of an infinite T4(0)A(0)6(0) water tape and discrete water hexamers in a hydrogen-bonded Ag(i) supramolecular framework

In a one-dimensional mixed-ligand Ag(i) coordination polymer, an infinite 1D T4(0)A(0)6(0) water tape and discrete water hexamers were simultaneously encapsulated.

Cyclic water clusters in tape-like and cage-like structures

Controlling the ratio of 2,2'-bpy to benzene-1,3,5-tricarboxylic acid produces two interesting complexes, namely [Co(2,2'-bpy)₃]·(SO₄)·8.5H₂O (1) and [Cu₂(BTCA) (2,2'-bpy)₄] (OH)·(2,2'-bpy)₀.₅·14H₂O (2) (H₃BTCA = benzene-1,3,5-tricarboxylic acid, 2,2'-bpy = 2,2'-bipyridine). We report the structural evidence in the solid state of discrete lamellar water cluster conformations. These units are found to act as supramolecular glue in the aggregation of cobalt (II) or copper (II) complexes to give three dimensional cage-like networks through hydrogen-bonding. It is interesting that the structure of complex 1 contains a 3D negatively charged cage.

Water-chloride and water-bromide hydrogen-bonded networks: influence of the nature of the halide ions on the stability of the supramolecular assemblies

Two compounds, namely, [TTPH(2)](Cl)(2) x 4 H(2)O (1) and [TTPH(2)](Br)(2) x 4 H(2)O (2), (TTP = 4'-p-tolyl-2,2':6',2''-terpyridine) were synthesized from purely aqueous media and characterized by physical techniques. In the solid-state structures of these compounds, interesting supramolecular assemblies are observed. In 1, an unusual staircase-like architecture of the tape of edge-shared planar water hexamer is of importance, where the chloride ions are at the two edges of the tape. In 2, the polymeric nature of the water-bromide assembly is of interest, where discrete open-cube water octamers are doubly bridged by bromide ions. Semiempirical and DFT calculations confirm that the nature of the anion indeed affects the topology of the water-halide assemblies. We conclude that the protonated [TTPH(2)](2+) species can act as appropriate receptors for halide ions, which in turn act as a matrix for the formation of polymeric 1D water-halide assemblies.