'Aggregation-Induced Emission' Active Mono-Cyclometalated Iridium(III) Complex Mediated Efficient Vapor-Phase Detection of Dichloromethane

Polarity responsive polysiloxanes with twisting intramolecular charge transfer effect for monitoring lipophagy process and the detection of volatile organic compounds

Polarity plays a critical role in biology and materials science, serving as a complex parameter. Imbalances in polarity within subcellular organelles are closely associated with various diseases. Moreover, volatile organic compounds (VOC) with low polarity pose significant health and safety risks, therefore, researchers have shown great interest in accurately detecting polarity. However, precise observation of polarity changes within organisms and identification of low-polarity volatile organic solvents are formidable challenges. To overcome these difficulties, we developed a versatile polymeric twisting intramolecular charge transfer (TICT) effect Polysiloxane-n (PDMS-n), utilizing polysiloxane molecular chains as "smart guides" to connect TICT molecules, inspired by the concept of "threading a needle." With the aid of PDMS-n, the process of polarity changes during cellular lipophagy was monitored in situ with high accuracy. Remarkably, the polarity changes of the local microstructure of the PDMS films were successfully visualized. PDMS-Films were also constructed, which enabled the recognition of Dichloromethane (DCM) gas during swelling. This work will contribute to the understanding of changes in cellular physiological processes, and facilitate the sensitive detection of VOCs.

An aggregation induced emission active bis-heteroleptic ruthenium(II) complex for luminescence light-up detection of pyrophosphate ions

A red emissive ruthenium(II) complex 1[PF6]2 of an amino ethanol substituted 1,10-phenanthroline-based ligand (L1) has been developed and characterized by spectroscopic analysis and single-crystal X-ray diffraction. Complex 1 shows an aggregation-induced emission (AIE) enhancement and forms nano-aggregates in the poor solvent water and highly dense polyethylene glycol (PEG) media. The possible reason behind the AIE properties may be the rigidity gained through weak supramolecular interactions between neighbouring phenanthroline ligands and PF₆^- counterions. The AIE properties were supported by UV-vis and photoluminescence (PL) spectroscopy and dynamic light scattering (DLS) studies to substantiate the formation of nano-aggregates and to understand the morphology of the aggregated particles, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies were performed. Compound 1[PF6]2 was highly selective towards pyrophosphate ions (PPi) over other phosphates such as ATP, ADP, AMP and H₂PO₄^- ions and other competitive anions in the PL spectroscopic channel in acetonitrile. The PL titrations of 1[PF6]2 with PPi in CH₃CN furnished the association constant K_a = 1.08 × 10⁴ M^-1 and the detection limit was calculated as low as 1.54 μM. The PPi detection has been established through the unique H-bonding interaction, supported by ¹H NMR titration. Finally, the cytotoxicity study and bioimaging were carried out for biological application. The complex shows very low cytotoxicity and good biocompatibility and is suitable for intracellular PPi imaging.

Multicolor Emissive Phosphorescent Iridium(III) Complexes Containing L-Alanine Ligands: Photophysical and Electrochemical Properties, DFT Calculations, and Selective Recognition of Cu(II) Ions

Three novel Ir(III) complexes, (ppy)₂Ir(L-alanine) (Ir1) (ppy = 2-phenylpyridine), (F₄ppy)₂Ir(L-alanine) (Ir2) (F₄ppy = 2-(4-fluorophenyl)pyridine), and (F_2,4,5ppy)₂Ir(L-alanine) (Ir3) (F_2,4,5ppy = 2-(2,4,5-trifluorophenyl)pyridine), based on simple L-alanine as ancillary ligands were synthesized and investigated. Due to the introduction of fluorine substituents on the cyclometalated ligands, complexes Ir1-Ir3 exhibited yellow to sky-blue emissions (λ_em = 464-509 nm) in acetonitrile solution. The photoluminescence quantum yields (PLQYs) of Ir1-Ir3 ranged from 0.48-0.69, of which Ir3 with sky-blue luminescence had the highest PLQY of 0.69. The electrochemical study and density functional theory (DFT) calculations show that the highest occupied molecular orbital (HOMOs) energy of Ir1-Ir3 are stabilized by the introduction of fluorine substituents on the cyclometalated ligands, while L-alanine ancillary ligand has little contribution to HOMOs and lowest unoccupied molecular orbitals (LUMOs). Moreover, Ir1-Ir3 presented an excellent response to Cu²⁺ with a high selectivity, strong anti-interference ability, and short response time. Such a detection was based on significant phosphorescence quenching of their emissions, showing the potential application in chemosensors for Cu²⁺.