Self-Assembly and Anion Encapsulation Properties of Cavitand-Based Coordination Cages

Fochi, Federica; Jacopozzi, Paola; Wegelius, Elina; Rissanen, Kari; Cozzini, Pietro; Marastoni, Elena; Fisicaro, E.; Manini, Paola; Fokkens, Roel H.; Dalcanale, Enrico

doi:10.1021/ja0103492

Cited by 186 publications

(86 citation statements)

References 38 publications

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“…[21] The 1 H and 13 C NMR spectra were particularly diagnostic for the macrocyclic mononuclear complexes 17 and 18, respectively, in which the methylene signals of the chelating dppe unit are deshielded, as expected for the cationic species relative to the neutral cis-[PdA C H T U N G T R E N N U N G (dppe)A C H T U N G T R E N N U N G (OTf) 2 ] precursor. Finally, the structural formulation of the proposed macrocycles 17 and 18 was firmly elucidated by ESI mass spectrometry.…”

Section: Resultsmentioning

confidence: 79%

The Assembly of Macrocyclic Bis‐ and Tetra‐β‐lactams with Embedded Platinum or Palladium Square‐Planar Centers

Pellico

Gallego

Ramírez‐López

et al. 2009

Chemistry A European J

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The synthesis, isolation, and full characterization of different types of stable, metal-assembled macrocyclic beta-lactams are reported. By using adequately functionalized bis-beta-lactams with defined stereochemistry as building blocks, a series of mono- and bimetallic Pd and Pt macrocycles has been prepared in good to quantitative yields. These novel structures combine the beta-lactam moiety with transition-metal fragments with cis-square-planar geometry and constitute a new class of metal-assembled cavities involving molecules with biological relevance as building blocks. By combining the adequate ligands, metallic fragments, and tuning the reaction conditions, different mono- and bimetallic macrocyclic beta-lactam cavities can be selectively obtained. Macrocycles with Pt-ethynyl groups are suitable to form host-silver triflate guest complexes in a tweezer fashion.

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Section: Resultsmentioning

confidence: 79%

The Assembly of Macrocyclic Bis‐ and Tetra‐β‐lactams with Embedded Platinum or Palladium Square‐Planar Centers

Pellico

Gallego

Ramírez‐López

et al. 2009

Chemistry A European J

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“…Non-covalent bond types such as hydrogen bonds, charge transfer interactions, van der Waals interactions, and metal coordination are weak and much less strong than covalent bonds. Thus, the relative stability of capsules made of these types of interactions is due only to the cooperative effects of the many existing interactions [19,20]. Generally, these latter types of molecular capsules allow reversible capture of guests.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of the geometrical and electronic structures and thermochemistry of spherophanes

et al. 2009

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A set of supramolecular cage-structuresspherophanes-was studied at the density functional B3LYP level. Full geometrical structure optimisations were made with 6-31G and 6-31G(d) basis sets followed by frequency calculations, and electronic energies were evaluated at B3LYP/6-31++G(d,p). Three different symmetries were considered: C1, Ci, and Oh. It was found that the bonds between the benzene rings are very long to allow π-electron delocalisation between them. These spherophanes show portal openings of 2.596 Å in Spher1, 4.000 Å in Meth2, 3.659 Å in Oxa3, and 4.412 Å in Thia4. From the point of view of potential host-guest interaction studies, it should also be noted that the atoms nearest to the centre of the cavities are carbons bonded to X groups. These supramolecules seem to exhibit relatively large gap HOMO−LUMO: 2.89 eV(Spher1),

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“…The robustness of the M-Py coordination allowed us to perform CSA in polar and competitive solvents like DMSO or acetonitrile, where the nitrile-based coordination cages immediately decompose (24). The solubility properties of cages 3a-h can be tuned by appropriately choosing counterion, chelating ligand and R substituents at the lower rim of the cavitand ligand.…”

Section: Resultsmentioning

confidence: 99%

“…The robustness of the pyridine-metal coordinative bond has been exploited to perform CSA in highly polar solvents, precluded to the first generation of cavitand-based coordination cages bearing nitrile moieties (24). Kinetically the platinum cages are stable at room temperature both in polar and apolar solvents.…”

Section: Resultsmentioning

confidence: 99%

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Design and self-assembly of wide and robust coordination cages

Pirondini

Bertolini

Cantadori

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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The self-assembly of a new class of coordination cages formed from two tetrapyridyl-substituted cavitands connected through four square-planar palladium or platinum complexes is reported. The shape of the internal cavity resembles an ellipsoid with a calculated volume of 840 Å 3 . The four lateral portals have a diameter of about 6 Å, large enough to allow the fast entrance͞ egress of counterions in solution. The platinum cages 3a,e cannot be disassembled using triethylamine as competitive ligand and they are kinetically stable at room temperature, whereas the palladium cages 3b-d, 3f-h are disassembled and kinetically labile under the same conditions. The different solubility properties of the cage components have allowed the extension of this selfassembly protocol to the liquid-liquid interface. cavitands M etal-directed self-assembly has been widely used to construct three-dimensional structures presenting internal cavities of molecular dimensions, capable of trapping ions and neutral molecules (1, 2). The ability of such container molecules to confine (3) and stabilize (4) their guests makes them particularly attractive for many potential applications ranging from catalysis (5, 6) to nanotechnology (for self-assembly in nanotechnology, see ref. 7; ref. 8). Specifically, surface-controlled self-assembly is rapidly emerging as a valuable tool for the generation of complex structures directly on solid supports (9-11). Unlike the covalent approach used for carcerands synthesis (12), the thermodynamic control of the process conveys interesting features, among which reversibility (13), selection (14), and self-repairing properties are the most interesting.Cavitand-based coordination cages are receiving increasing attention because of the versatility of cavitand platforms in terms of preorganization and synthetic modularity (15)(16)(17)(18)(19)(20). Strong metal-ligand interactions are necessary to operate cage selfassembly (CSA) in a wide range of solvents, to extend further these self-assembly protocols to solid-liquid and liquid-liquid interfaces.For this purpose we designed and synthesized new cavitands bearing pyridines (for references on cages derived from multidentate pyridine ligands, see ref. 21; refs. 22 and 23) instead of nitriles (24) at the upper rim as ligands for the coordination to the metal centers. CSA requires a cavitand with four pyridines preorganized in a diverging spatial orientation, pointing outward (o) the cavity, being designated the oooo isomer (for in͞out isomerism in cavitands, see ref. 25). Materials and MethodsGeneral. All commercial reagents were ACS reagent grade and used as received. All solvents were dried over 3-and 4-Å molecular sieves. Resorcinarenes 1a,b were prepared according to the literature (26). Metal precursors were prepared from the corresponding dichlorobis derivatives following established procedures (27-29). 1 H NMR were recorded on Bruker (Billerica, MA) AC300 (300 MHz) and AMX400 (400 MHz) spectrometers and all chemical shifts (␦) were reported in parts per milli...

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Self-Assembly and Anion Encapsulation Properties of Cavitand-Based Coordination Cages

Cited by 186 publications

References 38 publications

The Assembly of Macrocyclic Bis‐ and Tetra‐β‐lactams with Embedded Platinum or Palladium Square‐Planar Centers

The Assembly of Macrocyclic Bis‐ and Tetra‐β‐lactams with Embedded Platinum or Palladium Square‐Planar Centers

Theoretical study of the geometrical and electronic structures and thermochemistry of spherophanes

Design and self-assembly of wide and robust coordination cages

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