Solvent-induced structural transformation in a one-dimensional coordination polymer

We have rationally designed a one-dimensional coordination polymer (1D CP), termed 1D-DGIST-18, that exhibits intrinsic structural flexibility. This 1D CP enables its expansion into a three-dimensional network through supramolecular interactions involving coordinated solvents and/or ligands. The strategic selection of solvents for solvent exchange, prior to drying, significantly influences the structures of 1D-DGIST-18 by removing certain coordinating solvents and modulating π-π stacking. Consequently, a hierarchical porosity emerges, ranging from micro- to meso- to macroporous structures, which is attributed to its inherent structural dynamics. Additionally, the formation of excimers endows 1D-DGIST-18, when immersed in acetone, with 'turn-on' fluorescence, as evidenced by fluorescence decay profiles. These structural transitions within 1D-DGIST-18 are further elucidated using single-crystal X-ray diffractometry. The insights from this study provide a foundation for the design of materials with structural dynamics and tunable properties.

Effect of solvent inclusion on the structures and solid-state fluorescence of coordination compounds of naphthalimide derivatives and metal halides

The structural characteristics and solid-state fluorescence of coordination compounds formed between the fluorophore N-((3-pyridyl)methyl)-1,8-naphthalimide (3-pn) and a range of divalent metal halides, were investigated. Six new crystal structures, of the formula ML 2 X 2.solv, were obtained through the combination of the organic ligand L = 3-pn with the divalent metal halides CoX2 (X = Cl− or Br−) or ZnX2 (X = Cl− or Br−) in different solvents. It was found that solvent molecules are incorporated into all the structures, and that the same complex can incorporate different solvent molecules. The conformation of the complex molecule is determined by the solvent molecule incorporated into the structure. The fluorescence intensity is affected by the identity of the metal and halido ligand in the complex molecule, while the identity of the solvent molecule and the metal ion affects the emission wavelength. Thus, the solvent of crystallisation impacts on the solid-state fluorescence of the compounds, hence the same complex can be made to fluoresce at different wavelengths depending on the solvent of crystallisation.

Orientation of carbonyl groups in inclusion crystals formed from ketones with aromatic diimide-based macrocycles

Inclusion crystals were formed from ketones with aromatic diimide-based macrocycles possessing adamantane units, where the oxygen atoms of guests interacted with the electron-deficient π-surfaces of the aromatic diimides through CO⋯π contacts.

Hook, Line, and Sinker! Spectroscopic Studies of Bi-Modular Mono- and Bis-1,8-naphthalimide-Ru(bpy)3-conjugates as DNA "Light Switches"

Bi-chromophoric ruthenium polypyridyl complexes comprising one or two nitro-1,8-naphthalimide groups are shown to be effective DNA binders with off-on light switching properties. The binding to DNA was investigated using a combination of studies such as UV-visible absorption and emission titrations, thermal denaturation, and circular dichroism spectroscopy. The DNA affinity was shown to be sensitive to both the linker length and the number of naphthalimides (one vs two) contained in these systems and binding constants ranging from 10⁶ to 10⁷ M^-1 for salmon testes DNA. The strong DNA binding is attributed to the combination of naphthalimide intercalation and the electrostatic interaction of the ruthenium complex. Large emission enhancements from the metal to ligand charge transfer (MLCT) emission arising from the metal complex were observed upon DNA binding, which was attributed to the interruption of intramolecular electron transfer quenching processes. Moving the nitro substitution from the 4-position to the 3-position is found to result in modification of the DNA binding and the resulting optical properties. The off-on light switch phenomena reported demonstrate the potential of these complexes to act as DNA probes.

Structure analysis of inclusion crystals of diimide-based macrocycles with halocarbons

Inclusion crystals containing several halocarbons were formed by three types of diimide-based macrocycles. Iodomethane was encapsulated within the cavity of the macrocycle through halogen-related interactions.

Photophysical properties of Ag, Zn and Cd - N-(4-pyridylmethyl)-1,8-naphthalimide complexes: influences of π-stacking and C–H⋯O interactions

In solution ligand and complexes show similiar fluorescence emission whereas emission in solid samples are distinguishable.

Co-Inclusion of cyclic ethers and chloroform by a macrocycle with benzophenone-3,3′,4,4′-tetracarboxylic diimide units

Crystallization of a diimide-based macrocycle having adamantane parts and several cyclic ethers in chloroform provided inclusion crystals, where both guests were cooperatively accommodated within inner spaces between the macrocycles.

Stacking among the clips of the poly-aromatic rings of phenazine with hydroxy-aromatics and photophysical properties

Clip-like arrangements of molecules in the cocrystals of phenazine with hydroxy-aromatics in their respective self-assemblies and photophysical properties were presented. Phenazine cocrystals with 1,2-dihydroxybenzene provided assembly with butterfly-like arrangements. In these cocrystals, the phenazine molecules occurred in parallel pairs having extensive π-stacking. The clip-like cocrystals with 1,3-dihydroxybenzene also exhibited parallel pairs of phenazine molecules that were parallel cofacial π-stacked. The hydrated cocrystals of phenazine with 1,2,3-trihydroxybenzene had chains of parallel cofacial phenazine rings having three distinguishable π-separation distances among the centroids of the phenazine rings. Also, 2,7-dihydroxynaphthalene formed a clip-like cocrystal with phenazine, which encapsulated an additional molecule of phenazine. This cocrystal also provided chain-like parallel arrangements of the phenazine molecules. The emission and quantum yields of the cocrystals were determined by the integrating sphere method, which indicated that only the cocrystal of phenazine with 2,7-dihydroxynaphthalene showed monomer-like emission of phenazine and the rest of the cocrystals were in a quenched state. In the solution phase, quenching of the emission of hydroxynaphthalene was observed when phenazine was added to an independent solution of 2,7-dihydroxynaphthalene or another hydroxynaphthalene. However, when hydroxybenzenes were added to a solution of phenazine, fluorescence enhancements of phenazine occurred due to photo-electron transfer.

π-Stackings control the photoluminescence efficiencies in solids, whereas in solutions, the ON or OFF processes are dependent on the hydroxyaromatics.

Influence of the aromatic surface on the capacity of adsorption of VOCs by magnetite supported organic-inorganic hybrids

It has been recently evidenced that hybrid magnetic nanomaterials based on perylene diimide (PDI) dopamine and iron oxide nanoparticles are useful for the adsorption and determination of volatile organic compounds (VOCs). However, NDI compounds are expensive and difficult to handle compared to smaller size diimides. Therefore, in this manuscript a combined experimental and theoretical investigation is reported including the analysis of the effect of changing the aromatic surface on the ability of these magnetite supported organic-inorganic hybrid nanoparticles (NPs) to adsorb several aromatic and non-aromatic VOCs. In particular, two new hybrid Fe3O4NPs are synthesized and characterized where the size of organic PDI dopamine linker is progressively reduced to naphthalene diimide (NDI) and pyromellitic diimide (PMDI). These materials were utilized to fill two sorbent tubes in series. Thermal desorption (TD) combined with capillary gas chromatography (GC)/flame detector (FID) was used to analyze both front and back tubes. Adsorption values (defined as % VOCs found in the front tube) were determined for a series of VOCs. The binding energies (DFT-D3 calculations) of VOC-Fe3O4NP complexes were also computed to correlate the electron-accepting ability of the arylene diimide (PDI, NDI or PMDI) with the adsorption capacity of the different tubes. The prepared hybrids can be easily separated magnetically and showed great reusability.

High Performance Fluorescent Turn-On Probe for Amitriptyline Based on Hybrid Nanoassembly of Organic-Inorganic Nanoparticles

Fluorescence methods have gained enormous attention due to their ease in use, simplicity, selectivity and sensitivity. Fluorescent chemosensors respond instantly by converting molecular recognition to fluorescent signals. The consumption of pharmaceutical products by living beings is on great increase. The disposal of such compounds in the environment is a matter of great concern as these compounds enter aquatic environment and show accumulation in tissues of aquatic organisms. In the present study, we have utilized naphthalimide based receptors to fabricate organic nanoparticles (ONPs). These ONPs were used for the development of hybrid nanoassemblies, and the developed nanoassemblies were characterized with the help of transmission electron microscopy and dynamic light scattering studies. The photophysical studies were performed and the hybrid assembly developed using receptor 2 demonstrated a turn-on fluorescence emission behavior on binding with Amitriptyline. The present sensing system acted as promising candidate for determination of Amitriptyline among other contending drug molecules. The established system can recognize Amitriptyline up to a detection limit of 48 nM in aqueous medium. Electrochemical recognition studies show binding of hybrid nanoassembly of receptor 2 with Amitriptyline with limit of detection of 21 nM.

Photo-physical properties of salts of a di-topic imidazole-tethered anthracene derivative in solid and solution

Combined effects of Dexter-quenching and protonation to change the photoluminescence of a di-topic anthracene–amine conjugate by nitrophenols and aromatic carboxylic acids in solid and solution are presented.

Coordination chemistry of N-picolyl-1,8-naphthalimides: colourful low molecular weight metallo-gelators and unique chelation behaviours

A family of N-picolyl-1,8-napthalimide ligands display fascinating coordination chemistry and produce a series of robust and chemically responsive supramolecular metallo-gels.

Supramolecular coordination polymers using a close to ‘V-shaped’ fluorescent 4-amino-1,8-naphthalimide Tröger's base scaffold

A novel 4-amino-1,8-naphthalimide derived Tröger's base ligand L has been synthesised and subsequently used in the formation of two new supramolecular coordination polymers TB-Co-CP and TB-Cd-CP.