Sulfate-templated self-assembly of new M4L6 tetrahedral metal organic cages

Abstract

Six equivalents of N,N'-bis(4-aminobenzyl)urea, 12 equivalents of 2-formylpyridine and four equivalents of FeSO(4) or NiSO(4) undergo subcomponent self-assembly in aqueous solution to form tetrahedral cages around a single, encapsulated sulfate anion.

Synthesis and Applications of Endohedrally Functionalized Metal‐Ligand Cage Complexes

“…A similar strategy was employed by Kaifer, who used Fe II or Ni II ‐mediated iminopyridine multicomponent assembly for the formation of sulfate‐binding tetrahedra. In this case, the sulfate anion was required for assembly: other ions showed no cage formation …”

“…In this case, the sulfate anion was required for assembly: other ions showed no cage formation. [31] Other H-bond donors can be used to effect anion recognition. Alcohols have both H-bond donor and acceptor properties, and can provide a secondary layer of control in assembly and molecular recognition.…”

Solvent- and anion-induced interconversions of metal–organic cages

“…3 Herein, we report a versatile system in which discrete monomeric and dimeric interlocked cages can be obtained simultaneously on the basis of their solubility in different solvents and the formation of various kinetic or thermodynamic products can be controlled via anion templating (Schemes 1 and S1). The combination of amino-carbaldehyde/imine and metal-ligand coordination chemistries [12][13][14][15] has been used for the generation of the monomeric Pd2L4 and dimeric Pd2L8 cages via: 1) one-pot synthesis from 4,4'oxydianiline, 3-formylpyridine and [Pd(CH3CN)4](BF4)2/Pd(NO3)2 and 2) direct self-assembly from the pre-synthesized L ligand and Pd 2+ salts. The formation of discrete cages depends closely on the chosen solvents and anions (ESI, Figs.…”

Palladium‐Templated Subcomponent Self‐Assembly of Macrocycles, Catenanes, and Rotaxanes

“…The distance between the Pd II centers is 6.7694(6) , thereby providing a positively charged cleft. The solid-state structure reveals a BF 4 À ion within this cavity, sandwiched between the two Pd II centers. Tetrafluoroborate was also observed to bind within 3 in fast exchange on the NMR time scale in solution: the 19 F NMR spectrum of 3 in acetonitrile solution revealed the chemical shift of the anion to be shifted upfield by nearly one ppm compared to tetramethylammonium tetrafluoroborate in acetonitrile solution, which is comparable to shifts seen for the binding of this anion in other metal-organic hosts.…”

“…[1] By allowing amines and aldehydes to condense around a metal template, a variety of metallosupramolecular structures, such as capsules [2] and interlocked assemblies, [3] have been synthesized, with applications including anion binding [4] and molecular magnetism. [5] This has been made possible through the use of metal-ion templates including octahedral Fe II , [6] Ni II , [7] Co II , [8] Zn II , [1h] and Cd II ions, [9] as well as tetrahedral Cu I [10] ions and higher-coordinate lanthanides.…”