A pre-organized monomer-reservoir strategy to prepare multidimensional phosphorescent organoplatinum nanocrystals and suprastructures

The preparation of multidimensional nano-and microstructures,in particular suprastructures with well-defined morphology and bright emissions,is a challenging task in supramolecular assembly.For this purpose,a new type of amphiphilic diplatinum complexes is presented as an excellent building block to assemble into highly phosphorescent nanofibers by supramolecular Pt…Pt interactions.These organoplatinum supramolecular fibers are further used as a pre-organized monomer reservior for the metal ion-triggered post-transformation into crystalline nanoneedles,nanorods,nanobunches,microplates,and microflowers with controllable morphology and bright phosphorescence.A reverse transformation of the obtained nanorods into nanofibers is demonstrated with the aid of ethylenediamine tetraacetic acid.In contrast,the direct treatment of diplatinum complexes with different metal ions fails to give well-defined nano and microstructures,suggestive of the pre-organized role of nanofibers for the morphological transformation.Preliminary applications of these nano-and suprastructures in sensing temperature and organic vapours by emission signal changes are demonstrated.In contrast to the conventional hierarchical assembly,the pre-organized monomer-reservoir strategy disclosed in this study offers a versatile method for the synthesis of organic nano and suprastructures with multidimensional morphology and controllable emission properties.

Integrative self-assembly of covalent organic frameworks and fluorescent molecules for ultrasensitive detection of a nerve agent simulant

Binding of fluorescent molecules to the porous matrix through noncovalent interactions will synergistically expand their application spectrum. In this regard, we report an integrative self-assembly of molecule 1 with benzothiadizole and 9,9-dihexyl fluorene units, and covalent organic frameworks(COFs) via an emulsion-modulated polymerization process, within which molecules of 1 are able to interact with the scaffolds of COFs through CH-π interactions. Thus the π-πinteractions between the fluorescent molecules are largely suppressed, giving rise to their remarkable monomer-like optical properties. Of particular interest is that, given by the specific interaction between COFs and a nerve agent simulant diethyl chlorophosphite(DCP), these assembled composites show the ability of ultrasensitive detection of DCP with a detection limit of ~40 ppb. Moreover, the present integrative assembly strategy can be extended to encapsulate multiple fluorescent molecules, enabling the assemblies with white light emission. Our results highlight opportunities for the development of highly emissive porous materials by molecular selfassembly of fluorophores and molecular units of COFs.

Spontaneously bundled nanotubes exhibit greatly enhanced emission via inter-nanotube energy transfer

Spontaneously bundled nanotubes assembled from chiral perylene diimide molecules exhibit greatly enhanced emission via inter-nanotube excitation energy transfer. The formation of densely packed superstructures is an effective approach for high fluorescence quantum yield in assembled nanomaterials without compromising optoelectronic properties.