Solvent-driven chirality for luminescent self-assembled structures: experiments and theory

Disassembly of spherical structures into nanohelices by good solvent dilution

Supramolecular self-assembly of low molecular weight molecules into various organic nanostructures has attracted considerable research interest. However, preparing organic nanostructures through a top-down method, such as the disassembly of one large structure into many smaller nanoscale nanostructures, still remains a big challenge. Here, we make use of anti-solvent method to regulate the hierarchical self-assembly of an achiral C3-symmetric molecule in THF/water to prepare various nanostructures, including spherical structures, nanofibers, nanoribbons and nanotwists. Interestingly, the spherical structures could disassemble into nanohelices through good solvent dilution, providing a nanoscale top-down method to prepare organic nanostructures.

Effect of substituents on the 1O2 production and biological activity of (N^N^N)Pt(py) complexes

Twelve (N^N^N)platinum pyridyl complexes, (N^N^N)Pt(pyF), were synthesised and investigated for their singlet oxygen generation and potential biological activities. They exhibited 1IL and 1MLCT absorption transitions at approximately 325 and 360 nm, identified through TD-DFT calculations. Luminescence was observed only in the L1-derived compounds in solution, with a dual emission with the main contribution of phosphorescence under deaerated conditions. Room temperature phosphorescence was detected in all solid-state cases. Electron-withdrawing substituents at specific positions (R1 and X) and the number of fluorine atoms in R2 were found to enhance the photosensitizing capabilities of these compounds. Biological assessments, including cytotoxicity and photocytotoxicity, were conducted to evaluate their potential as chemotherapeutic agents and photosensitizers. Complexes with chloro substitution in the N^N^N tridentate ligand of the central pyridine ring exhibited promising chemotherapeutic properties. Ancillary pyridine ring substitution became significant under irradiation conditions, with fluoromethylated substituents enhancing cytotoxicity. Complex 2-CF3 was the most efficient singlet oxygen producer and a highly effective photosensitizer. CHF2-substituted complexes also showed improved photosensitizing activity. DNA binding studies indicated moderate interactions with DNA, offering insights into potential biological applications.

Investigating the Impact of Packing and Environmental Factors on the Luminescence of Pt(N^N^N) Chromophores

Four Pt(II)(N^N^N) compounds featuring DMSO coordination at the fourth position were synthesized. Ligands varied in terms of pyridyl central ring (hydrogen/chlorine substituent) and lateral rings (triazoles with CF3 substitution or tetrazoles). Coordination to pyridine yielded tetra-nitrogen coordinated Pt(II) complexes or Pt-functionalized polymers using commercial 4-pyridyl polyvinyl (PV) or dimethylaminopyridine. Luminescence behaviors exhibited remarkable environmental dependence. While some of the molecular compounds (tetrazole derivatives) in solid state displayed quenched luminescence, all the polymers exhibited 3MMLCT emission around 600 nm. Conversely, monomer emission was evident on poly(methyl methacrylate) or polystyrene matrices. DFT calculations were used to analyze the aggregation of the complexes both at the molecular level and coordinated to the PV polymer and their influence on the HOMO-LUMO gaps.

Dual supramolecular chirogenesis based on platinum(II) metallotweezers

Optically active platinum(II) metallotweezers demonstrate both self-complexation and host-guest complexation capabilities, leading to two distinct supramolecular chirogenic signals in the visible region.

The Martini Model in Materials Science

The Martini model, a coarse-grained force field initially developed with biomolecular simulations in mind, has found an increasing number of applications in the field of soft materials science. The model's underlying building block principle does not pose restrictions on its application beyond biomolecular systems. Here, the main applications to date of the Martini model in materials science are highlighted, and a perspective for the future developments in this field is given, particularly in light of recent developments such as the new version of the model, Martini 3.