Strategic Synthesis of ‘Picket Fence’ Porphyrins Based on Nonplanar Macrocycles

Traditional ‘picket fence’ porphyrin systems have been a topic of interest for their capacity to direct steric shielding effects selectively to one side of the macrocycle. Sterically overcrowded porphyrin systems that adopt macrocycle deformations have recently drawn attention for their applications in organocatalysis and sensing. Here we explore the combined benefits of nonplanar porphyrins and the old molecular design to bring new concepts to the playing field. The challenging ortho-positions of meso-phenyl residues dodecasubstituted porphyrin systems led us to transition to less hindered para- and meta-sites and develop selective demethylation based on the steric interplay. Isolation of the symmetrical target compound [2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetrakis(3,5-dipivaloyloxyphenyl)porphyrin] was investigated under two synthetic pathways. The obtained insight was used to isolate unsymmetrical [2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetrakis(2-nitro-5-pivaloyloxyphenyl)porphyrin]. Upon separation of the atropisomers, a detailed single-crystal X-ray crystallographic analysis highlighted intrinsic intermolecular interactions. The nonplanarity of these systems in combination with ‘picket fence’ motifs provides an important feature in the design of supramolecular ensembles.<br>

Strategic Synthesis of ‘Picket Fence’ Porphyrins Based on Nonplanar Macrocycles

Traditional ‘picket fence’ porphyrin systems have been a topic of interest for their capacity to direct steric shielding effects selectively to one side of the macrocycle. Sterically overcrowded porphyrin systems that adopt macrocycle deformations have recently drawn attention for their applications in organocatalysis and sensing. Here we explore the combined benefits of nonplanar porphyrins and the old molecular design to bring new concepts to the playing field. The challenging ortho-positions of meso-phenyl residues dodecasubstituted porphyrin systems led us to transition to less hindered para- and meta-sites and develop selective demethylation based on the steric interplay. Isolation of the symmetrical target compound [2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetrakis(3,5-dipivaloyloxyphenyl)porphyrin] was investigated under two synthetic pathways. The obtained insight was used to isolate unsymmetrical [2,3,7,8,12,13,17,18-octaethyl-5,10,15,20-tetrakis(2-nitro-5-pivaloyloxyphenyl)porphyrin]. Upon separation of the atropisomers, a detailed single-crystal X-ray crystallographic analysis highlighted intrinsic intermolecular interactions. The nonplanarity of these systems in combination with ‘picket fence’ motifs provides an important feature in the design of supramolecular ensembles.<br>

Graphene nanoribbon-based supramolecular ensembles with dual-receptor targeting function for targeted photothermal tumor therapy

Triple negative breast cancer (TNBC) is one of the most malignant subtypes of breast cancer. Here, we report the construction of graphene nanoribbon (GNR)-based supramolecular ensembles with dual-receptor (mannose and...

Tetra-(benzo-24-crown-8)-phthalocyanines as a platform for supramolecular ensembles: Synthesis and interaction with viologen

The synthesis of a series of novel tetra-(benzo-24-crown-8)-phthalocyanines (Mg(II), Ni(II) and Co(II)) as well as a modified procedure for the free-base ligand and its Zn(II) and Cu(II) complexes are reported. The tendency of these phthalocyanines to undergo supramolecular cofacial dimerization induced by interaction with a viologen ([Formula: see text]-di(but-3-ynyl)-4,4[Formula: see text]-bipyridinium) was investigated by UV-vis absorption and EPR spectral studies in solution. The nature of the metal cation in phthalocyanine, the concentration, as well as the solvent all influenced the assembly processes.

Pillar[5]arene-based tunable luminescent materials via supramolecular assembly-induced Förster resonance energy transfer enhancement

Supramolecular ensembles based on AIE-active pillararenes exhibit strongly enhanced emission accompanied with obvious colour changes upon assembly, where supramolecular assembly-induced enhanced emission and FRET process play key roles.

Supramolecular ensembles modified by near-infrared dyes and their biological applications

This review presents recently developed supramolecular ensembles modified by near-infrared dyes. We discussed the construction of these near-infrared dyes-based ensembles and their biological application.

Soft Micro- and Nanorobotics

Micro- and nanorobots can perform a number of tasks at small scales, such as minimally invasive diagnostics, targeted drug delivery, and localized surgery. During the past decade, the field has been transformed in many ways, one of the most significant being a transition from hard and rigid micro- and nanostructures to soft and flexible architectures. Inspired by the dynamics of flexible microorganisms, researchers have focused on developing miniaturized soft components such as actuators, sensors, hinges, joints, and reservoirs to create soft micro- and nanoswimmers. The use of organic structures such as polymers and supramolecular ensembles as functional components has brought more complex features to these devices, such as advanced locomotion strategies and stimulus-triggered shape transformations, as well as other capabilities. A variety of microorganisms and contractile mammalian cells have also been utilized as microengines and integrated with functional synthetic materials, producing bending or deformation of the functional materials to initiate motion. In this review, we consider several types of soft micro- and nanorobots in terms of their architecture and design, and we describe their locomotion mechanisms and applications.