A theoretical study on the on-off phosphorescence of novel Pt(ii)/Pt(iv)-bisphenylpyridinylmethane complexes

An in-depth theoretical study on the Pt(ii)/Pt(iv)-bisphenylpyridinylmethane complexes was carried out, which focused on the geometric/electronic structures, excitation procedures, on-off phosphorescence mechanisms, and structure-optical performance relationships. The key roles of the linkages (LK) connected in the middle of phenylpyridines were carefully investigated using multiple wavefunction analysis methods, such as non-covalent interaction (NCI) visualizations and natural bond orbital (NBO) studies. The phosphorescence-off phenomenon was considered by hole-electron analysis and visualizations, spin-orbit coupling (SOC) studies, and NBO analysis. Through these investigations, the relationship of the substituents in LK and the optical performances were revealed, as well as the fundamental principles of the phosphorescence-quenching mechanism in Pt(iv) complexes, which pave the way for further performance/structural renovation works. In addition, an intuitive visualization method was developed using a heatmap to quantitatively express the SOC matrix elementary (SOCME), which is helpful for big data simplification for phosphorescence analysis.

Electrochromic behavior of fac-tricarbonyl rhenium complexes

Tricarbonyl rhenium complex shows good electrochromic performance with a colored stage of green, rapid response and good switching stability.

Bimetallic-based food sensors for meat spoilage: Effects of the accepting metallic unit in Fe(II)CNMA (MA = Pt(II) or Au(I)) on device selectivity and sensitivity

Technologies for monitoring meat spoilage are important to ensuring consumer safety. As dimethyl sulfide (DMS) is a reliable marker for meat freshness, sensitive and selective DMS sensors are of great interest. Herein, two trinuclear cyano-bridged bimetallic donor-acceptor ensembles, Fe^II(bpy)₂(CN)₂-[Pt^II(DMSO)Cl₂]₂ (1) and Fe^II(bpy)₂(CN)₂-[Au^ICl]₂, were synthesized, and corresponding solid-supported sensors were fabricated to determine the effect of the acceptor metal (M_A) on DMS detection. Changing M_A from Au^I to Pt^II improved the sensitivity and selectivity owing to changes in the relative thermodynamic stabilities of the complex and M_A-DMS adduct. When applied to real meat samples, 1 exhibited a linear spectroscopic response to DMS, even in the presence of interfering compounds, with a method detection limit of 1.0 ppm. The total bacteria count and gas chromatography-mass spectrometry results revealed that the spectroscopic signal generated by 1 correlated with the microbial growth level and DMS concentration during meat spoilage.

A reversible fluorescence chemosensor for sequentially quantitative monitoring copper and sulfide in living cells

We report a novel, selective and sensitive strategy for the sequentially "ON-OFF-ON" fluorescent detection of Cu(2+) and S(2-) based on a fluorescein derivative, FL. The specific binding of FL towards Cu(2+) in aqueous and biological media led to the intensive green fluorescence quenching and a notable increase of the absorbance maximum at 480 nm. In the presence of S(2-), the intensity and overall pattern of the fluorescence emission and UV-vis spectra of FL-Cu(2+) ensemble were recovered since the abolishment of paramagnetic Cu(2+). This displacement approach exhibited highly specificity, and sensitivity with detection limits of 3 nM for Cu(2+) and 150 nM for S(2-). The fluorescence "ON-OFF-ON" circle can be repeated to a minimum of 5 times by the alternative addition of Cu(2+) and S(2-), implying that FL is a renewable dual-functional chemosensor. The biocompatibility of FL toward breast carcinoma cells, MDA-MB-231 was confirmed by MTT assay. The reversible "ON-OFF-ON" fluorescent response of FL to Cu(2+) and S(2-) in living system was further confirmed by confocal fluorescence imaging of living cells. The quantification of Cu(2+) and S(2-) in single intact cell was realized by the flow cytometry analysis.

A new fluorescent chemosensor for highly selective and sensitive detection of inorganic phosphate (Pi) in aqueous solution and living cells

A new fluorescein-based chemosensor, FP-Fe³⁺, was developed for the detection of inorganic phosphate (Pi) in aqueous solution and living cells.