Hierarchical Self-Assembly of Polyoxometalate-Based Organo Palladium(II) Metallomacrocycles via Electrostatic Interactions

Abstract

The design and synthesis of a supramolecular square composed of polyoxometalate-based hybrid donors and ethylenediamine palladium­(II) nodes are reported. The structure of the metallomacrocycle scaffold was inferred by diffusion NMR, small-angle X-ray scattering (SAXS), and molecular modeling. The metallomacrocycle scaffold that contains negatively and positively charged subunits can further self-assemble owing to a competition between the solvation energy of the discrete species and intermolecular electrostatic interactions. When the dissociating character of the solvent was lowered or when in the presence of a protic solvent, different types of multiscale organizations (vesicles and pseudo-1D structures) were selectively formed and were characterized by SAXS and transmission electron microscopy.

Exploring the self-assembly of dumbbell-shaped polyoxometalate hybrids, from molecular building units to nanostructured soft materials

“…Electrostatic interactions between the POMs result in a small decrease in intensity at small wave vectors, which prevents the observation of the Guinier regime as previously observed. [8][9][10]41 The SAXS diagrams of all dumbbell-like Co(II) and Co(III) complexes display oscillations as we have observed in other supramolecular systems. 8,9 These oscillations reveal characteristic distances larger than the POM dimension and have, in the low q region, a higher intensity than the starting building units, as a consequence of larger structures.…”

“…[5][6][7] In this context we recently described the hierarchical self-assembly of organic/ inorganic polyoxometalate (POM)-based hybrids in which the POM is covalently bonded to remote binding sites. [8][9][10] POMs are nanosized polyanionic molecular metal-oxo clusters that constitute original building units for the elaboration of multifunctional materials [11][12][13][14][15][16][17] owing to their multiple properties (such as electron reservoirs) 18 and sensitiveness to different interactions. [19][20][21][22] As they are polyanionic species they establish strong electrostatic interactions with cationic species.…”

Photocurrent generation from visible light irradiation of covalent polyoxometalate–porphyrin copolymers

“…The zinc-βoctaethylporphyrin (ZnOEP) was purchased from Sigma-Aldrich, and The 5,15-ditolylporphyrin (H2T2P) was purchased from SAS PorphyChem ® . Keggin-type polyoxovanadate [PW11Si2O40C26H16N2] TBA3 (abbreviated Py-PW11Si2-Py) and Dawson-type polyoxovanadate [P2W17Si2O62C26H16N2] TBA6 (abbreviated Py-P2W17Si2-Py) were synthesized following the reported synthetic procedures [18][19].…”

Antagonistic mixing in micelles of amphiphilic polyoxometalates and hexaethylene glycol monododecyl ether

“…[9][10][11] Therefore, the development of suitable methods to modify POM frameworks with organic groups through electrostatic interactions and covalent linkages have been a focus of interest in this field. Due to the strong stabilities of covalent linkages compared to electrostatic interactions, studies have endeavoured to functionalise the POM cage through building covalent bonds to organic groups, [12][13][14] to achieve well-organised nanostructures. Interesting self-assembled amphiphilic structures have been detected, such as vesicles, [15][16][17] cylindrical micelles 16 or emulsions.…”