Heteroleptic Metallosupramolecular Complexes of Bodipy Dyes as Energy Transfer Cassettes

Heteroleptic Triple-Stranded Metallosupramolecules with Hydrophobic Inner Voids

The systematic combination of well-defined coordination spheres and multiple types of ligands (heteroleptic) can lead to the generation of hierarchical metallosupramolecules with a high level of complexity and functionality. In particular, a specific multilevel coordination-driven assembly through the initiate generation of multinuclear clusters can form unique heteroleptic multiple-stranded supramolecular complexes. Herein, we report novel triple-stranded nickel-based supramolecules constructed from two different ditopic ligands ([1,1':3',1''-terphenyl]-4,4''-dicarboxylate (TP) and 2,6-pyridinedicarboxylate (PDA)) and a nickel precursor. The solid-state structures of the as-synthesized supramolecules revealed that three PDA ligands are employed to fabricate a tetranuclear ({Ni₄}) cluster, and two {Ni₄} clusters are assembled to form the final triple-stranded metallosupramolecules by three TP ligands. The bridging TP ligands also provide large inner voids with highly hydrophobic environments. Structural investigation of the generated complexes provided a deeper understanding of the aspects driving the formation of heteroleptic supramolecules, which is crucial for the design of multiple-strands with desired morphologies and functionalities.

Recent advances in heteroleptic multiple-stranded metallosupramolecules

Well-ordered combination of defined coordination spheres and multiple types of ligands (heteroleptic) in a given structure can expand the structural complexity and functional diversity of the resulting metallosupramolecules. Such heteroleptic metallosupramolecular architectures are expected to afford advanced utility in a variety of applications. In this concise review article, recent advances in the development of multi-nuclear-cluster-based heteroleptic multiple-stranded (HLMS) metallosupramolecules are summarized and demonstrated. To construct HLMS metallosupramolecules, one type of multitopic ligands can be employed for building up multiple strands, while another type of ligands can be utilized to construct multi-nuclear clusters. Most HLMS metallosupramolecules adopt helical geometries and have high molecular symmetry, which can be key factors for the structural completion. HLMS metallosupramolecules can be used as basic building blocks for the fabrication of higher-order polymeric or discrete assembly architectures with well-defined geometries.

Reversal aggregation-induced circular dichroism from axial chirality transfer via self-assembled helical nanowires

Two chiral binaphthyl-based enantiomers, (R/S)-7, can produce gradual reversal AICD signals from solution to aggregation, which can be attributed to axial chirality transfer to self-assembled helical nanowires in aggregation state.

BODIPY based self-healing fluorescent gel formation via acylhydrazone linkage

Polymeric BODIPY derivatives with reactive functional groups undergo reversible formation of covalent bonds leading to self-healing properties.

Synthesis of energy transfer cassettes via click and Suzuki–Miyaura cross coupling reactions

Novel cassettes capable of energy transfer involving simple synthetic methodsviz., click reaction at C-8 position and palladium catalyzed Suzuki–Miyaura cross coupling at C-6 position of imidazo[1,2-a]pyrazine, have been represented.

Spectroscopic and crystallographic investigations of novel BODIPY-derived metal-organic frameworks

To explore new 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-derived metal-organic frameworks (MOFs), we employed 2,6-dicarboxyl-1,3,5,7-tetramethyl-8-phenyl-4,4-difluoroboradiazaindacene (H2L) as a ligand to successfully synthesize five coordination polymers, namely, {[Zn2(L)2(bpp)]·2H2O·2EtOH}n (1), {[Cd2(L)2(bpp)]·2H2O·EtOH}n (2), {[Cd2(L)(bpe)3(NO3)2]·2H2O·DMF·EtOH}n (3), {[Cd(L)(bpe)0.5(DMF)(H2O)]}n (4), and {[Cd(L)(bpe)0.5]·1.5H2O·DMF}n (5) (bpp = 1,3-bi(4-pyridyl)propane, bpe = 1,2-bi(4-pyridyl)ethane). Except for two 2D-layer coordination polymers 3 and 4, the rest samples exhibit 3D metal-organic frameworks with certain pore sizes, especially MOFs 1 and 5. Spectroscopic and crystallographic investigations demonstrate that the absorption and emission energies of the BODIPY chromophores are sensitive to the coordination modes. Moreover, in case 2, the transition metal centers coordinated with the dicarboxylate ligands L(2-) are capable of forming the two BODIPY units in coplanar arrangements (θ = 37.9°), simultaneously suppressing the uncommon J-dimer absorption band centered at 705 nm with a long tail into the near-infrared region at room temperature. On the other hand, in comparison with the ligand H2L, the emission of monomer-like BODIPY in case 3 is enhanced in the solid state by a considerably long distance between the parallel BODIPY planes (about 14.0 Å).

Halogenated boron-dipyrromethenes: synthesis, properties and applications

Synthesis and properties of halogenated boron-dipyrromethenes and their applications in developing various BODIPY systems are described in this review.

From self-sorted coordination libraries to networking nanoswitches for catalysis

This feature article sketches our long way from the development of dynamic heteroleptic coordination motifs to the self-sorting of multi-component libraries and finally the design of a new family of triangular nanomechanical switches, which are useful for ON–OFF control of catalysis and in bidirectional communication.

Synthesis and properties of rhenium(I) bridged boron-dipyrromethene dyad

We synthesized the hexa-coordinated Re ( I ) bridged BODIPY dyad 1 in decent yield by thermal reaction of benzimidazole substituted BODIPY 2 with Re ( CO )5 Cl . The dyad 1 was characterized by 1 H , 13 C , 11 B , 19 F NMR, ESI-MS, FTIR, UV-vis, and electrochemical techniques. In Re ( I ) bridged dyad 1, the Re ( I ) ion is hexa-coordinated and coordinates with nitrogen atoms of two benzimidazole units, three axial carbonyl ligands and one chloride atom. The presence of three carbonyl groups in dyad 1 was verified by 13 C NMR and IR spectroscopy. The absorption and steady-state fluorescence spectra of Re ( I ) bridged BODIPY dyad showed a slightly broad and hypsochromically shifted absorption and emission bands compared to BODIPY 2. The electrochemical studies indicated that, the Re ( I ) bridge BODIPY dyad 1 was easy to reduce compared to BODIPY 2 supporting the electron deficient nature dyad upon Re ( I ) ion binding. The molecular structure of dyad 1 was further elucidated by DFT computational studies.

Designing BODIPY-based probes for fluorescence imaging of β-amyloid plaques

Styryl-congutated BODIPY dyes which are structurally similar to known Aβ peptide binding dyes, were designed and synthesized.

Ion responsive near-IR BODIPY dyes: two isomers, two different signals

Different responses of two isomeric tetrastyryl-BODIPY's were studied, shedding light on the path to near IR sensors for metal ions.