Electron-donating Moieties Research Articles

Triplet Harvesting in Trifluoromethyl Quinoxaline Derivatives via TADF and RTP Mechanisms

In this study, we explore the impact of donor strength on the photophysical properties of novel trifluoromethyl quinoxaline derivatives, which incorporate various electron-donating moieties exhibiting distinct conformational characteristics. The triplet harvesting mechanisms within these quinoxaline systems are facilitated through thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP), both of which can be modulated by subtle structural alterations in the donor unit. The derivatives demonstrate varying photophysical properties, including pure RTP activity, dual activity (exhibiting both TADF and RTP), and pure TADF, contingent upon the nature of the electron-donating moieties employed. Notably, the intersystem crossing (ISC) rates are significantly higher than the rates of radiative decay, leading to diminished fluorescence quantum yields (ΦDF) of the compounds in toluene solutions. However, embedding the TADF compounds within a rigid polystyrene (PS) matrix results in a remarkable enhancement of ΦDF due to significant reduction of nonradiative pathways related to intramolecular twisting. A considerable conformational disorder of the polymer doped films was observed resulting in non-exponential fluorescence decay and significant shifts of prompt and delayed fluorescence in time-resolved spectra.

High-Performance Photocatalytic Hydrogen Generation Using Robust Dianchoring Photosensitizers.

A novel series of donor-donor-π-acceptor (D-D-π-A) 9,9'-dihexylfluorene-based dianchoring organic dyes, each featuring distinct bridging electron-donating moieties, have been synthesized and characterized. Their performances in photocatalytic hydrogen evolution (PHE) were evaluated, taking into account of their photophysical and electrochemical attributes. Remarkably, (Z)-3-(5-(4-((4-(5-((E)-2-carboxy-2-cyanovinyl)thiophen-2-yl)phenyl)(9,9-dihexyl-9H-fluoren-2-yl)amino)phenyl)thiophen-2-yl)-2-cyanoacrylic acid achieved an active and robust H2 generation system with a turnover number (TON) of up to 17 400 in 126 h, with a production of 1090 μmol (26.3 mL) of hydrogen. The initial turnover frequency (TOFi), initial activity (activityi), and initial apparent quantum yield (AQYi) were 808 h-1, 505 mmol g-1 h-1, and 8.65%, respectively, under visible light irradiation in water. This photosensitizer is considered one of the most effective and durable systems for photocatalytic hydrogen production that attached to molecular Pt-TiO2, as stated out in the literature using organic dyes under visible light, when compared the TOF and TON values. The experimental results demonstrated that the dianchoring dyes with bridging units could significantly enhance PHE performance, maintaining justifiable durability over prolonged irradiation.

Molecular engineering on tyrian puprle natural dye as TiO2 based fined tuned photovoltaic dye material: DFT molecular analysis

In this research, molecular modification is employed to see the enhancement in the efficiency of Tyrian Purple (TP), a natural dye, for organic photovoltaic materials.By using Density Functional Theory (DFT) based molecular modeling, seven new structures are designed with pi spacer to extend electron donor moieties. Teheir Frontier Molecular Orbital (FMO) analysis demonstartes their charges with a similar pattern of distributions over their Highest Occupied and Lowed Unocuupied Molecular Orbitals (HOMO/lUMO). This analysls also show their energy gaps (Egaps) to range around 2.97-3.02 eV. Their maximum absorption wavelength (λmax) demosntartes 486-490 nm range to indicate their tendency of absorbing light efficiently. Their Transition Density Matrix (TDM) analysis also reveals their facile electronic transitions without a significant charges over spacers. From calculating their photovoltaic paramters, their Light Harvesting Efficiency (LHE) reaches to 72.4-95.5 %. Also their Open Circuit Voltage (Voc) varies across 1.16-1.34 V. It is found that dyes actively adsorb onto TiO2 clusters to demonstrate their promise for tuning their Conduction Band (CB). This research is an effort for to evaluate the structural correlations to the developm photovoltaic materials through molecular-level design and optimization.

Molecular weight fraction-specific transformation of natural organic matter during hydroxyl radical and sulfate radical oxidation

Aquatic natural organic matter (NOM) is one of the main scavengers of reactive species (e.g., •OH and SO4•−) during oxidation processes and undergoes complex transformations. Here, the organic content, optical properties, and redox state in various MW fractions and bulk Suwannee River NOM (SRNOM) were simultaneously evaluated during •OH and SO4•− oxidation processes for the first time. The SRNOM transformation pathways were specific to radical species and MW fractions, which was evidenced by a proportional decrease in electron-donating moieties and chromophores during •OH oxidation but a higher decrease in electron-donating moieties than chromophores during SO4•− oxidation, particularly in lower MW fractions (<3 kDa). The •OH decomposed reactive moieties mainly via aromatic ring opening or depolymerization in all MW fractions. SO4•− oxidation followed a similar pathway in higher MW fractions (>3 kDa) but mainly formed compounds with UV-absorbing properties (e.g., quinones) in lower MW fractions (<3 kDa). With competitive kinetics and depolymerization model, •OH was quantified as approximately 10 times more reactive towards MW fractions than SO4•−. However, the SO4•− concentrations were approximately 10 times those of •OH, resulting in comparable performance to •OH oxidation. SRNOM depolymerization by •OH and SO4•− resulted in formation of more precursors of disinfection byproducts than the parent constituents, especially for •OH. This work improves our understanding of the transformation of specific SRNOM fractions during radical oxidation processes.

Uncovering excited state behaviours associated with electron-withdrawing CN and electron-donating TPA moieties on SAA derivatives: a theoretical study

Inspired by the excellent photochemical characteristics exhibited by salicylaldehyde azine (SAA) derivatives, our current endeavour primarily revolves around delving into the intricacies of photo-induced excited state reactions for its electron-donating and electron-withdrawing moieties derivatives (i.e. CN-SAA-CN, CN-SAA-TPA and TPA-SAA-TPA). Our simulations reveal push–pull-substituted-dependent photoexcitation that could significantly affect excited state intramolecular proton transfer (ESIPT) reaction for SAA derivatives. Constructing potential energy surfaces (PESs), we unveil the ultrafast ESIPT mechanism due to the low potential barriers. Additionally, by comparing the differences of barriers among CN-SAA-CN, CN-SAA-TPA and TPA-SAA-TPA, we present regulative manner for SAA derivatives by substituting electron-donating and electron-withdrawing moieties. We sincerely anticipate that the modulation of push–pull substitutions on excited state behaviours will pave the way for ground-breaking advancements in luminescent materials.

Bithieno[3,4-c]pyrrole-4,6-dione-Based Wide-Bandgap Donor Polymers for Efficient Polymer Solar Cells.

The polymer solar cells (PSCs) have garnered substantial interest owing to their lightweight, cost-effectiveness, and flexibility, making them ideal for large-scale roll-to-roll manufacturing. In this study, two wide-bandgap (WBG) donor polymers, PFBiTPD and PClBiTPD, utilizing bithieno[3,4-c]pyrrole-4,6-dione (BiTPD) as the electron-accepting unit and fluorinated/chlorinated benzo[1,2-b:4,5-b']dithiophene (BDT) as the electron-donating moiety are designed and synthesized. The polymers demonstrated large optical bandgaps (exceeding 1.80eV) and are blended with ITIC-4F to form the active layers in PSCs. The PFBiTPD-based devices showed a well-dispersed fibrillar network, facilitating efficient charge generation and transport. Thus, these devices attained a power conversion efficiency (PCE) of 8.60%, featuring a fill factor (FF) of 62.89%, an open-circuit voltage (Voc) of 0.88V and a short-circuit current density (Jsc) of 15.54mA cm-2. In contrast, PClBiTPD-based devices displayed lower performance due to less favorable morphology. The study underscores the importance of polymer design and morphology control in optimizing the photovoltaic performance of PSCs.

From Coordination to π‐Hole Chemistry of Transition Metals: Metalloporphyrins as a Case of Study

AbstractHerein we have evidenced the formation of favorable π‐hole Br⋅⋅⋅metal noncovalent interactions (NCIs) involving elements from groups 9, 11 and 12. More in detail, M (M=Co2+, Ni2+, Cu2+ and Zn2+) containing porphyrins have been synthesized and their supramolecular assemblies structurally characterized by means of single crystal X‐ray diffraction and Hirshfeld surface analyses, revealing the formation of directional Br⋅⋅⋅M contacts in addition to ancillary hydrogen bond and lone pair‐π bonds. Computations at the PBE0‐D3/def2‐TZVP level of theory revealed the π‐hole nature of the Br⋅⋅⋅M interaction. In addition, the physical nature of these NCIs was studied using Quantum Chemistry methodologies, providing evidence of π‐hole Spodium and Regium bonds in Zn2+ and Cu2+ porphyrins, in addition to unveiling the presence of a π‐hole for group 9 (Co2+). On the other hand, group 10 (Ni2+) acted as both electron donor and acceptor moiety without showing an electropositive π‐hole. Owing to the underexplored potential of π‐hole interactions in transition metal chemistry, we believe the results reported herein will be useful in supramolecular chemistry, organometallics, and solid‐state chemistry by i) putting under the spotlight the π‐hole chemistry involving first row transition metals and ii) unlocking a new tool to direct the self‐assembly of metalloporphyrins.

From Coordination to π-Hole Chemistry of Transition Metals: Metalloporphyrins as a Case of Study.

Herein we have evidenced the formation of favorable π-hole Br⋅⋅⋅metal noncovalent interactions (NCIs) involving elements from groups 9, 11 and 12. More in detail, M (M=Co2+, Ni2+, Cu2+ and Zn2+) containing porphyrins have been synthesized and their supramolecular assemblies structurally characterized by means of single crystal X-ray diffraction and Hirshfeld surface analyses, revealing the formation of directional Br⋅⋅⋅M contacts in addition to ancillary hydrogen bond and lone pair-π bonds. Computations at the PBE0-D3/def2-TZVP level of theory revealed the π-hole nature of the Br⋅⋅⋅M interaction. In addition, the physical nature of these NCIs was studied using Quantum Chemistry methodologies, providing evidence of π-hole Spodium and Regium bonds in Zn2+ and Cu2+ porphyrins, in addition to unveiling the presence of a π-hole for group 9 (Co2+). On the other hand, group 10 (Ni2+) acted as both electron donor and acceptor moiety without showing an electropositive π-hole. Owing to the underexplored potential of π-hole interactions in transition metal chemistry, we believe the results reported herein will be useful in supramolecular chemistry, organometallics, and solid-state chemistry by i) putting under the spotlight the π-hole chemistry involving first row transition metals and ii) unlocking a new tool to direct the self-assembly of metalloporphyrins.

Enhancing the performance of pyridyl carboxamide-N,N-dimethyl amino chalcone (PCC) as a dye sensitizer for dye-sensitized solar cells (DSSCs) through the incorporation of electron donor moieties

This study has focused on enhancing the performance of pyridyl carboxamide-N,N-dimethyl amino chalcone (PCC) as a sensitizer for dye-sensitized solar cells (DSSCs) by strategically incorporating electron donor moieties identified in a literature review. Our reviewing the previous reports highlights the pivotal role of electron donors in optimizing light harvesting, electron injection, and overall power conversion efficiency in organic dye sensitizers, particularly those following a donor-bridge-acceptor (D-π-A) architecture. The selected donor moieties, including dithieno[3,2-b:2′,3′-d]thiophene (DTT), benzodithiophene (BDT), triphenylamine (TPA), carbazole (CBZ), and triazatruxene (TAZ), are systematically introduced into the molecular structure of PCC (abbreviated as PCC-DTT, PCC-BDT, PCC-TPA, PCC-CBZ, and PCC-TAZ, respectively). The performance of these modified compounds is rigorously evaluated using density functional theory (DFT) methods. Validation results revealed that the most reliable method for PCC derivative characterization involved the combination of the functional B3PW91 with a 6-31G(d) basis set. The results indicate that the incorporation of certain donor moieties, particularly BDT, significantly enhances the electronic and optical properties of PCC, including lower HOMO energy levels, a narrow energy gap (Egap), enhanced absorption intensity, and a redshift in absorption peaks. Evaluation of photovoltaic properties including electron injection (ΔGinj), and open circuit voltage (Voc), indicated facilitating spontaneous electron injection from the dyes to the TiO2 conduction band. Notably, PCC-TAZ demonstrated the lowest electron regeneration (ΔGreg), suggesting a notable potential for efficient electron regeneration.

Bis-Ortho-Donor-Modification of Boracyclic π-Electron Systems beyond Steric Protection to Produce Thermally Activated Delayed Fluorescence Materials.

Polycyclic π-conjugated compounds that contain tricoordinate boron atoms at their periphery represent an attractive class of materials with electron-accepting character. Their molecular design generally requires the introduction of a bulky aryl group onto the boron atom, where it provides predominantly kinetic stabilization. The addition of extra functionality to the aryl group on the boron atom can be expected to further expand the potential utility of this class of materials. Herein, we report the synthesis of a series of boracyclic π-conjugated molecules with firm ortho B⋅⋅⋅N nonbonding interactions by introducing N-containing electron-donors at the ortho-positions of the aryl group on the boron atom. X-ray crystallographic analysis revealed that the combination of a planar boracyclic π-skeleton with only sp2 carbons and a strong electron-donating phenothiazine moiety results in a particularly short B⋅⋅⋅N distance. Theoretical study provided insights into the inherent nature of the B⋅⋅⋅N interaction. Owing to their donor-acceptor (D-A) structures, these molecules exhibit substantially red-shifted fluorescence in solution, albeit that the fluorescence quantum yields (ΦF) are low. In contrast, when incorporated into films, these compounds exhibit thermally activated delayed fluorescence (TADF) with improved ΦF values. Organic light-emitting diodes (OLEDs) fabricated using the ortho-donor-substituted derivatives exhibit orange-red electroluminescence.

Study on four pyridine-based difluoroboron compounds for mechanofluorochromic behaviors, the ink-free writing and detection of latent fingerprints

With the increasing demand for multifunctional aggregation-induced emission materials, four pyridine-based difluoroboron compounds (1, 2, 3, and 4) with the anthryl unit as an electron donor and difluoroboron moiety as the electron acceptor were designed and successfully synthesized. It found that four compounds displayed significantly intramolecular charge transfer characteristics and solvatochromism phenomena. The other compounds possessed mechanofluorochromic behaviors under external mechanical stimulation except compound 1, owing to its lesser change value of the dipole moment between the ground and excited states. More importantly, they exhibited potential application in the field of ink-free writing due to reversible mechanochromism during the grinding and fumigation process. Additionally, four compounds were used for detection of latent fingerprints on the glass surface due to their excellent aggregation effects in the THF/water mixtures. This research provides a reference for exploring multifunctional aggregation-induced emission difluoroboron compounds with brightness luminescence.

Polycationic Open-Shell Cyclophanes: Synthesis of Electron-Rich Chiral Macrocycles, and Redox-Dependent Electronic States.

π-Conjugated chiral nanorings with intriguing electronic structures and chiroptical properties have attracted considerable interests in synthetic chemistry and materials science. We present the design principles to access new chiral macrocycles (1 and 2) that are essentially built on the key components of main-group electron-donating carbazolyl moieties or the π-expanded aza[7]helicenes. Both macrocycles show the unique molecular conformations with a (quasi) figure-of-eight topology as a result of the conjugation patterns of 2,2',7,7'-spirobifluorenyl in 1 and triarylamine-coupled aza[7]helicene-based building blocks in 2. This electronic nature of redox-active, carbazole-rich backbones enabled these macrocycles to be readily oxidized chemically and electrochemically, leading to the sequential production of a series of positively charged polycationic open-shell cyclophanes. Their redox-dependent electronic states of the resulting multispin polyradicals have been characterized by VT-ESR, UV/Vis-NIR absorption and spectroelectrochemical measurements. The singlet (ΔES-T=-1.29 kcal mol-1) and a nearly degenerate singlet-triplet ground state (ΔES-T(calcd)=-0.15 kcal mol-1 and ΔES-T(exp)=0.01 kcal mol-1) were proved for diradical dications 12+2⋅ and 22+2⋅, respectively. Our work provides an experimental proof for the construction of electron-donating new chiral nanorings, and more importantly for highly charged polyradicals with potential applications in chirospintronics and organic conductors.

Production of redox-active-reactive filter material from charcoal

The surficial and textural features of a pyrogenic carbonaceous material (charcoal) was modulated with acidic Piranha solution (i.e., 1:3 30% H2O2 to H2SO4) to produce a redox-active adsorbent for the simultaneous adsorption and reduction of Cr(VI) in groundwater sample. The optimal modification time of 60 s is required to transform the raw charcoal to an efficacious redox-active adsorbent (MCh). The MCh surface was imbued with electron donor moieties that is required for the direct conversion of the adsorbed Cr(VI) to Cr(III). The rate parameters for Cr(VI) adsorption by the MCh were initial concentration dependent. The GW system variables had minimal influence on the performance of the MCh, which showed that the MCh is capable of effective performance within broad process variables. The direct conversion of Cr(VI) to Cr(III) on the MCh surface was affirmed. The treatment of Cr(VI) contaminated GW in a microcosm real-life system was highly effective over the period of study (40 hours). The residual Cr(VI) concentration in the hourly sample collection ranged between undetectable (i.e.,<0.01), at the inception, to 1.77 mg/L at the 40th hour. The pH values of the treated water were not vitiated, and the EC (μs cm− 1) values continually reduced over time.

Visualization of polarity changes in endoplasmic reticulum (ER) autophagy and rheumatoid arthritis mice with near-infrared ER-targeted fluorescent probe

The crucial cellular activities for maintaining normal cell functions heavily rely on the polarity of the endoplasmic reticulum (ER). Understanding how the polarity shifts, particularly in the context of ER autophagy (ER-phagy), holds significant promise for advancing knowledge of disorders associated with ER stress. Herein, a polarity-sensitive fluorescent probe CDI was easily synthesized from the condensation reaction of coumarin and dicyanoisophorone. CDI was composed of coumarin as the electron-donating moiety (D), ethylene and phenyl ring as the π-conjugation bridge, and malononitrile as the electron-accepting moiety (A), forming a typical D-π-A molecular configuration that recognition in the near-infrared (NIR) region. The findings suggested that as the polarity increased, the fluorescence intensity of CDI decreased, and it was accompanied by a redshift of emission wavelength at the excitation wavelength of 524 nm, shifting from 641 nm to 721 nm. Significantly, CDI exhibited a notable ability to effectively target ER and enabled real-time monitoring of ER-phagy induced by starvation or drugs. Most importantly, alterations in polarity can be discerned through in vivo imaging in mice model of rheumatoid arthritis (RA). CDI has been proven effective in evaluating the therapeutic efficacy of drugs for RA. ER fluorescent probe CDI can be optically activated in lysosomes, providing a sensitive tool for studying ER-phagy in biology and diseases.

Synthesis, Photophysical Properties, Theoretical Studies, and Living Cancer Cell Imaging Applications of New 7-(Diethylamino)quinolone Chalcones.

In this article, three unsymmetrical 7-(diethylamino)quinolone chalcones with D-π-A-D and D-π-A-π-D type push-pull molecular arrangements were synthesized via a Claisen-Schmidt reaction. Using 7-(diethylamino)quinolone and vanillin as electron donor (D) moieties, these were linked together through the α,β-unsaturated carbonyl system acting as a linker and an electron acceptor (A). The photophysical properties were studied, revealing significant Stokes shifts and strong solvatofluorochromism caused by the ICT and TICT behavior produced by the push-pull effect. Moreover, quenching caused by the population of the TICT state in THF-H2O mixtures was observed, and the emission in the solid state evidenced a red shift compared to the emission in solution. These findings were corroborated by density functional theory (DFT) calculations employing the wb97xd/6-311G(d,p) method. The cytotoxic activity of the synthesized compounds was assessed on BHK-21, PC3, and LNCaP cell lines, revealing moderate activity across all compounds. Notably, compound 5b exhibited the highest activity against LNCaP cells, with an LC50 value of 10.89 μM. Furthermore, the compounds were evaluated for their potential as imaging agents in living prostate cells. The results demonstrated their favorable cell permeability and strong emission at 488 nm, positioning them as promising candidates for cancer cell imaging applications.

D-π-A type dicyanoethylene derivatives modified by tetraphenylethylene exhibiting aggregation-induced emission and high-contrast mechanofluorochromism

Based on a rational design strategy by combining an electron-withdrawing dicyanoethylene unit and electron-donating tetraphenylethylene moiety, we successfully synthesized two π-conjugated molecules Ph-TPE-MMN and NA-TPE-MMN. According to the optical research and theoretical calculation results, they had highly distorted conformations, D-A type molecular structure and definite intramolecular charge transfer (ICT) properties. Moreover, two molecules Ph-TPE-MMN and NA-TPE-MMN showed aggregation-induced emission (AIE) properties in the THF/water mixture at higher fw (water fraction). Ph-TPE-MMN and NA-TPE-MMN also exhibited fluorescence response to external force. The emitting color of both had changed greatly before and after grinding. The maximum emission wavelengths of Ph-TPE-MMN and NA-TPE-MMN were redshifted by 46 nm and 33 nm, respectively, implying high-contrast mechanofluorochromism. Notably, mechanofluorochromic process also showed a good reversible. XRD experiments indicated that mechanofluorochromic mechanism originated from changes in molecular stacking in solid state.

The role of Fe(IV) in the zero-valent iron biochar activated persulfate system for treatment of contaminants of emerging concern

In this paper, Fe(IV) was analyzed in the zero-valent iron biochar (ZVI-BC) activated persulfate (PS) process with methyl phenyl sulfoxide (PMSO) as the probe compound. Without a reaction terminator, PMSO degradation continued during the sample holding time, resulting in significant errors in the kinetics analysis. When 1 mM NaNO2, 1 mM NH2OH, 10 mM Na2S2O3, or 10 mM dimethyl sulfoxide were used as terminators, the concentrations of PMSO and its oxidation product, methyl phenyl sulfone (PMSO2), were effectively maintained without changes during the sample holding period. Furthermore, the terminators did not interfere with PMSO or PMSO2 analysis by high performance liquid chromatography. In addition to Fe(IV), free radical (i.e., SO4−, OH, O2−) and nonradical (i.e., 1O2) reactive species were also involved in the ZVI-BC/PS system; however, Fe(IV) was the predominant reactive species. Organic contaminants with electron-donating moieties rapidly reacted with Fe(IV), and the relative contribution of Fe(IV) to overall contaminant degradation decreased as the solution pH was increased. Overall, this study provided new insights into the quantitative analysis of Fe(IV) in the ZVI-BC/PS system and its application to treatment of organic contaminants in solutions with variable water quality.

Real-time monitoring of abnormal mitochondrial viscosity in glioblastoma with a novel mitochondria-targeting fluorescent probe.

Glioblastoma is the most fatal and insidious malignancy, due to the existence of the blood-brain barrier (BBB) and the high invasiveness of tumor cells. Abnormal mitochondrial viscosity has been identified as a key feature of malignancies. Therefore, this study reports on a novel fluorescent probe for mitochondrial viscosity, called ZVGQ, which is based on the twisted intramolecular charge transfer (TICT) effect. The probe uses 3-dicyanomethyl-1,5,5-trimethylcyclohexene as an electron donor moiety and molecular rotor, and triphenylphosphine (TPP) cation as an electron acceptor and mitochondrial targeting group. ZVGQ is highly selective, pH and time stable, and exhibits rapid viscosity responsiveness. In vitro experiments showed that ZVGQ could rapidly recognize to detect the changes in mitochondrial viscosity induced by nystatin and rotenone in U87MG cells and enable long-term imaging for up to 12 h in live U87MG cells. Additionally, in vitro 3D tumor spheres and in vivo orthotopic tumor-bearing models demonstrated that the probe ZVGQ exhibited exceptional tissue penetration depth and the ability to penetrate the BBB. The probe ZVGQ not only successfully visualizes abnormal mitochondrial viscosity changes, but also provides a practical and feasible tool for real-time imaging and clinical diagnosis of glioblastoma.

Developing NIR xanthene-chalcone fluorophores with large Stokes shifts for fluorescence imaging.

A series of novel near-infrared (NIR) xanthene-chalcone fluorophores were constructed through a modular synthesis with the electron-donating xanthene moiety and the electron-withdrawing chalcone moiety. These fluorophores are convenient for fluorescence imaging in living cells, benefiting from their NIR emissions (650-710 nm), large Stokes shifts (>100 nm), moderate quantum yields and low cytotoxicity. The substituted hydroxyl group of the xanthene-chalcone fluorophore HCA-E facilitates the development of multifunctional fluorescent probes. As an example, a highly sensitive and selective probe N-HCA-E for glutathione (GSH) detection was developed based on the fluorophore HCA-E. A 4-nitrobenzenesulfonyl (4-Ns) group was introduced to cage the hydroxyl group of HCA-E, which was used as a selective recognition site for the thiol of GSH and an effective fluorescence quencher. Probe N-HCA-E revealed NIR "turn-on" fluorescence (709 nm) for endogenous and exogenous GSH detection in lysosomes with a large Stokes shift (129 nm) and high anti-interference ability.

Design and synthesis of versatile ligand precursors based on phosphonium ylides for palladalactam formation and catalytic investigation.

A new series of ligand precursors designed for the synthesis of palladalactams has been developed. These precursors are easily accessible through a one-step reaction involving 2-chloro-N-phenylacetamide and a wide choice of various monophosphines, offering tunable electronic and steric properties within the ligand framework. The stability of both ligand precursors and resulting palladalactams in ambient air enhances their practical applicability. A newly synthesized palladalactam, featuring an electron-donating triethylphosphine moiety on the anionic phosphonium ylide ligand scaffold exhibited promising catalytic activities in the Mizoroki-Heck coupling reaction between aryl chlorides and alkenes. Theoretical calculations further affirmed that the ligand system in the complex is the most electron-donating, forming the strongest Pd-C bond compared to other complexes with alternative phosphine moieties.