Prism[2]dihydrophenazines: Synthesis, Configurational Analysis, and Supramolecular Tessellation through Exo-Wall Interactions.

Macrocyclic arenes have gained considerable attention for their structural diversity and widespread applications. In this research, a new kind of macrocyclic arenes, namely prism[2]dihydrophenazines (anti-P2P20, syn-P2P20, and P2P22), composed of two dihydrophenazine derivatives subunits bridged by methylene groups, were conveniently synthesized by AlCl3-catalyzed one-pot condensation in 1,2-dichloroethane. Both anti-P2P20 and its isomer syn-P2P20 exhibited flexible and convertible conformation with narrow cavity, while P2P22 possessed rigid and rhombic-like skeleton due to the more steric hindrance on subunits. In addition, the selection of electron-deficient guest was found to influence the outside binding behavior of syn-P2P20. Fantastic regular supramolecular tessellation was fabricated by tiling of syn-P2P20 with tetrafluoro-1,4-benzoquinone (TFB) through the exo-wall interactions. Using 1,5-difluoro-2,4-dinitrobenzene (DFN) as a linker, only the regular 2D network superstructure with periodic units in a plane was obtained through cocrystallization. This work not only reports the construction of supramolecular tessellations by using prism[2]dihydrophenazines as building blocks, but also provides a new perspective for the design of macrocyclic arenes and fabrication of 2D supramolecular materials.

Exploring Efficient Dual-Phase Emissive Fluorophores with High Mobility by Integrating a Rigid Donor and Flexible Acceptor.

Developing luminogens with a high emission efficiency in both single-molecule and aggregate states, as well as high mobility, shows promise for advancing the iteration and update of organic optoelectronic materials. However, achieving a delicate balance between the plane configuration of luminophores and the strong exciton interactions of aggregates is a formidable task from the molecular design perspective. This dilemma was overcome by integrating a rigid donor and flexible acceptor to establish donor-acceptor (D-A) type emitters. The π-conjugate-extended donor ensures the substantial planarity of these molecules, allowing strong emission in solution with photoluminescence quantum yield values of 86% and 75%. Furthermore, the restricted molecular motion of the aggregation-induced emission moiety and the formation of J-aggregates reduce the quenching effect, leading to a high emissive efficiency of 85% and 91% in the aggregate state. The mildly distorted D-A geometry builds moderate electrostatic interaction, resulting in high mobility with µM,h of 7.12 × 10-5 and 3.27 × 10-4 cm2/V s. Additionally, an improved synthesized procedure for terminal E-configured acrylonitrile with metal-free and concise reaction conditions is presented. The successful application of the synthesized compounds in organic light-emitting diode devices demonstrates the practicability of the molecular design strategy with connecting a rigid donor and flexible acceptor.

Risk factors for bacteremia and mortality due to multidrug-resistant Acinetobacter baumannii: a retrospective study.

This research aimed to determine the relationships between the risk factors for nosocomial multidrug-resistant Acinetobacter baumannii (MDRAB) bacteremia and associated mortality. We analyzed 144 patients treated for A. baumannii bacteremia, including 120 patients with MDRAB bacteremia, from March 2015 to March 2020, in this retrospective study. The overall bacteremia-related mortality rate was 48.6%. The mortality rates were 25.0% and 53.3% for non-MDRAB and MDRAB bacteremia, respectively. Risk factors for the development of MDRAB bacteremia were prior use of cephalosporins [odds ratio (OR): 8.62; P < .001], carbapenems (OR: 15.04; P < .001), or quinolones (OR: 5.02; P = .040); indwelling urinary catheters (OR: 21.38; P < .001); and respiratory tract as the source of bacteremia (OR: 75.33; P < .001). Patients with elective surgeries were inclined to develop non-MDRAB bacteremia (OR: 0.45; P = .029). High scores in the Acute Physiology and Chronic Health Evaluation II (OR: 1.321; P < .001) and Sequential Organ Failure Assessment (OR: 1.326; P < .001) were risk factors for mortality from MDRAB infection. In summary, higher mortality rates occur in patients with MDRAB bacteremia, and risk factors include prior use of cephalosporins, carbapenems, or quinolones. Urinary catheters and the respiratory tract as sources of the infection increase the risk of MDRAB bacteremia.

Producing Bilayer Graphene Oxide via Wedge Ion-Assisted Anodic Exfoliation: Implications for Energy and Electronics.

Electrochemical synthesis has emerged as a promising approach for the large-scale production of graphene-based two-dimensional (2D) materials. Electrochemical intercalation of ions and molecules between graphite layers plays a key role in the synthesis of graphene with controllable thickness. However, there is still a limited understanding regarding the impact of intercalant molecules. Herein, we investigated a series of anionic species (i.e., ClO4-, PF6-, BF4-, HSO4-, CH3SO3-, and TsO-) and examined their wedging process between the weakly bonded layered materials driven by electrochemistry. By combining cyclic voltammetry, X-ray diffraction (XRD), and Raman spectroscopy, along with density functional theory (DFT) calculations, we found that stage-2 graphite intercalation compounds (GICs) can be obtained through intercalation of ClO4-, PF6-, or BF4- anions into the adjacent graphene bilayers. The anodic exfoliation step based on ClO4--GIC in (NH4)2SO4 (aq.) resulted in the formation of bilayer-rich (>57%) electrochemically exfoliated graphene oxide (EGO), with a high yield (∼85 wt %). Further, the physicochemical properties of these EGO can be readily customized through electrochemical reduction and modification with different surfactants. This versatility allows for precise tailoring of EGO, making it feasible for energy and electronic applications such as electrodes in electrochemical capacitors and functional composites in wearable electronics.

Dual Ratio and Ultraprecision Quantification of Mitochondrial Viscosity in Ferroptosis Enabled by a Vibration-Based Triple-Emission Fluorescent Probe.

Ferroptosis is a new mode of cell death with major morphological changes in mitochondria, including structural shrinkage and increased membrane density, indicating the mitochondrial abnormality during this process. Viscosity, as one of the crucial microenvironmental parameters for characterizing the mitochondrial state, is thought to be highly involved in the ferroptosis. Herein, we present a single fluorescent probe (PPAC-C4) for the dual ratio and ultrahigh-accuracy quantification of mitochondrial viscosity. This probe is constructed by linking a mitochondria-targeting cation fragment on a vibration-based fluorescent scaffold whose fluorescence exhibits the rare triple emission (480, 533, and 628 nm) depending on the viscosity. The intensity ratios of 480 nm/628 nm and 533 nm/628 nm can be used to monitor the viscosity changes in a double self-calibration manner and finally afford an average viscosity value with improved precision. By virtue of this pattern, we reveal that the mitochondrial viscosity will increase from 43.58 to 152.05 cP in A549 cells during the ferroptosis. This dual-ratio probe with triemission not only shows great potential in the study of ferroptosis and ferroptosis-related diseases but also proposes a new concept for ultraprecision quantitative analysis.

Exploring the Depth-Dependent Microviscosity inside a Micelle Using Butterfly-Motion-Based Fluorescent Probes.

The viscosity distribution of micellar interiors from the very center to the outer surface is dramatically varied, which has been distinguished in theoretical models, yet it remains highly challenging to quantify this issue experimentally. Herein, a series of fluorophore-substituted surfactants DPAC-Fn (n = 3, 5, 7, 9, 11, 13, and 15) are developed by functionalizing the different alkyl-trimethylammonium bromides with the butterfly motion-based viscosity sensor, N,N'-diphenyl-dihydrodibenzo[a,c]phenazine (DPAC). The immersion depth of DPAC units of DPAC-Fn in cetrimonium bromide (C16TAB) micelles depends on the alkyl chain lengths n. From deep (n = 15) to shallow (n = 3), DPAC-Fn in C16TAB micelles exhibits efficient viscosity-sensitive dynamic multicolor emissions. With external standards for quantification, the viscosity distribution inside a C16TAB micelle with the size of ∼4 nm is changed seriously from high viscosity (∼190 Pa s) in the core center to low viscosity (∼1 Pa s) near the outer surface. This work provides a tailored approach for powerful micelle tools to explore the depth-dependent microviscosity of micellar interiors.

Highly Solvent Resistant Small-Molecule Hole-Transporting Materials for Efficient Perovskite Quantum Dot Light-Emitting Diodes.

Perovskite quantum dot light-emitting diodes (Pe-QLEDs) have been shown as promising candidates for next-generation displays and lightings due to their unique feature of wide color gamut and high color saturation. Hole-transporting materials (HTMs) play crucial roles in the device performance and stability of Pe-QLEDs. However, small-molecule HTMs have been less studied in Pe-QLEDs due to their poor solvent resistance and low hole mobility. In this work, three novel small-molecule HTMs employing benzimidazole as the center core, named X4, X5, and X6, were designed and synthesized for application in Pe-QLEDs. One of the tailored HTM-X6 exhibits excellent solvent resistant ability to the perovskite quantum dot (QD) inks due to its proper solubility and low surface energy. Our result clearly demonstrated that the synergistic effect of poor solubility and low surface energy facilitates the achievement of good solvent resistance to perovskite QD inks. As a result, a promising maximal external quantum efficiency (EQE) of 14.1% is achieved in X6-based CsPbBr3 Pe-QLEDs, which is much higher than that of X4 (9.16%) and X5 (6.60%)-based devices, which is comparable to the PTAA reference (EQE ∼ 15.8%) under the same conditions. To the best of our knowledge, this is the first example that a benzimidazole-based small-molecule HTM demonstrated a good application in Pe-QLEDs. Our work provides new guidance for the rational design of small-molecule HTMs with high solvent resistance for efficient Pe-QLEDs and other photoelectronic devices.

Dynamic monitoring of self-assembly by confining conformational changes of butterfly-motion-based molecules.

A simple dynamic monitoring strategy for chiral self-assembly is achieved by confining the bent-to-planar evolution observed in N,N'-diphenyl-dihydrodibenzo[a,c]phenazine derivatives (DPAC-R/S-GLD). Besides, this approach provides a facile pathway to fabricate architectures with circularly polarized luminescence (CPL) properties.

Sequential Multistep Excited-State Structural Transformations in N,N'-Diphenyl-dihydrodibenzo[a,c]phenazine Fluorophores.

We demonstrate that a single polycyclic π-scaffold can undergo sequential multistep excited-state structural evolution along the bent, planar, and twisted conformers, which coexist to produce intrinsic multiple fluorescence emissions in room-temperature solution. By installing a methyl or trifluoromethyl group on the ortho-site of N,N'-diphenyl-dihydrodibenzo[a,c]phenazine (DPAC), the enhanced steric effects change the fluorescence emission of DPAC from a dominant red band to well-resolved triple bands. The ultra-broadband triple emissions of ortho-substituted DPACs range from ≈350 to ≈850 nm, which is unprecedented for small fluorophores with molecular weight of <500. Ultrafast spectroscopy and theoretical calculations clearly reveal that the above dramatic changes originate from the influence of steric hindrance on the shape of excited state potential energy surface (S1 PES). Compared to the steep S1 PES of parental DPAC, the introduction of ortho-substituent is shown to make the path of structural evolution in S1 wider and flatter, so the ortho-substituted derivatives exhibit slower structural transformations from bent to planar and then to twisted forms, yielding intrinsic triple emission. The results provide the proof of concept that the bent, planar, and twisted emissive states can coexist in the same S1 PES, which greatly expand the fundamental understanding of the excited-state structural relaxation.

H-bond interaction traps vibrating fluorophore in polyurethane matrix for bifunctional environmental monitoring.

A simple strategy is presented for the bifunctional detection of environmental organic vapor and temperature by utilizing H-bond interactions to trap a butterfly-vibration-based fluorophore (DPAC-OH) in a polyurethane (PU) matrix. The method opens up a new path for large-scale environmental inspections and the design of dual-response luminescent materials.

Ameliorated Neurogenesis Deficits in Dentate Gyrus May Underly the Pronounced Antidepressant Effect of TREK-1 Potassium Channel Blockade in Rats with Depressive-like Behavior.

Depression is considered to be the most common mental disorder and is probed by several studies that chronic mild stress contributes to depression, and fortunately, most antidepressants ameliorate depressive-like behavior accompanied with reversed hippocampal neurogenesis defects. In our present study, we confirmed that different antidepressants repaired the stress-induced neuronal and behavioral deficits by modulating adult hippocampal neurogenesis. Antidepressant treatment restored the adult hippocampal neurodegeneration, which was impaired by chronic unpredicted mild stress displaying decreased proliferation and neuronal differentiation but increased apoptosis of newly formed neurons in dentate gyrus. Notably, sucrose preference ratio significantly correlated with both neuronal differentiation proportion and newborn apoptosis proportion, suggesting a mechanistic relationship between neurogenesis and behavior. Indeed, the neotype TREK-1 potassium channel blocker expressed an earlier and pronounced antidepressant manifestation compared to the traditional selective serotonin-reuptake inhibitors fluoxetine. We therefore conclude that the administration of TREK-1 potassium channel antagonism can reverse the depressive deficits caused by chronic stress quickly via regulation of adult hippocampal neurogenesis.

Inhibition of NLRP1-Dependent Pyroptosis Prevents Glycogen Synthase Kinase-3ß Overactivation-Induced Hyperphosphorylated Tau in Rats.

Our previous study indicated that inhibition of NLRP1-dependent pyroptosis could decrease intracerebroventricular (ICV) injection of a protein kinase A (PKA) agonist- or streptozotocin (STZ)-induced hyperphosphorylated tau. In this study, we used a glycogen synthase kinase-3ß (GSK-3ß) overactivation rat model to reconfirm our previous results. ICV injection of wortmannin (WT, a PI3K inhibitor) and GF-109203X (GFX, a PKC inhibitor) was used to induce overactivation of GSK-3ß in rats. We injected NLRP1 siRNA together with WT/GFX to evaluate the effect of the inhibition of NLRP1-dependent neuronal pyroptosis on hyperphosphorylated tau. Our results indicated that ICV injection of NLRP1 siRNA prevented ICV-WT/GFX-induced neuronal death, further improving the spatial memory of the rats in the Morris water maze test. ICV injection of NLRP1 siRNA downregulated the expression of ASC, caspase-1, and GSDMD and the contents of IL-1ß and IL-18 in rat brains. ICV injection of NLRP1 siRNA also decreased hyperphosphorylated tau and the activity of GSK-3ß. Thus, these results support our previous study that NLRP1-dependent pyroptosis could enhance hyperphosphorylation of tau protein.

Photoconductance from the Bent-to-Planar Photocycle between Ground and Excited States in Single-Molecule Junctions.

Single-molecule conductance measurements for 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine (DPAC) may offer unique insight into the bent-to-planar photocycle between the ground and excited states. Herein, we employ DPAC derivative DPAC-SMe as the molecular prototype to fabricate single-molecule junctions using the scanning tunneling microscope break junction technique and explore photoconductance dependence on the excited-state structural/electronic changes. We find up to ∼200% conductance enhancement of DPAC-SMe under continuous 340 nm light irradiation than that without irradiation, while photoconductance disappears in the case where structural evolution of the DPAC-SMe is halted through macrocyclization. The in situ conductance modulation as pulsed 340 nm light irradiation is monitored in the DPAC-SMe-based junctions alone, suggesting that the photoconductance of DPAC-SMe stems from photoinduced intramolecular planarization. Theoretical calculations reveal that the photoinduced structural evolution brings about a significant redistribution of the electron cloud density, which leads to the appearance of Fano resonance, resulting in enhanced conductance through the DPAC-SMe-fabricated junctions. This work provides evidence of bent-to-planar photocycle-induced conductance differences at the single-molecule level, offering a tailored approach for tuning the charge transport characteristics of organic photoelectronic devices.

Interplay of Steric Effects and Aromaticity Reversals to Expand the Structural/Electronic Responses of Dihydrophenazines.

To gain insights into the coupling of conformational and electronic variables, we exploited steric hindrance to modulate a polycyclic skeleton with a bent conformation in the S0 state and a twisted conformation in the S1 state under the guidance of photoexcited aromaticity reversals. Polycyclic 5,10-dihydrophenazine (DHP) adopted a bent structure in S0 but involved a bent-to-planar transformation in S1 due to the excited-state aromaticity of the 8π-electron central ring. The N,N'-locations and 1,4,6,9-sites of the DHP skeleton provided a versatile chemical handle for fine-tuning intramolecular steric hindrance. Specifically, N,N'-diphenyl-5,10-dihydrophenazine (DPP-00) and its derivatives DPP-10-DPP-22 were synthesized with different numbers of methyl groups on the 1,4,6,9-sites. X-ray crystal analyses suggested that the DHP skeletons of DPP-00-DPP-22 had more bending configurations along the N···N axis with an increase in the number of methyl groups. Following the bending-promoted interruption of π-conjugation, the absorption spectra of DPP-00-DPP-22 significantly blue-shifted from 416 to 324 nm. By contrast, the emission bands exhibited a reverse shift to longer wavelengths from 459 to 584 nm as the number of methyl substituents increased. Theoretical calculations revealed that introducing methyl groups caused the planar DHP skeleton in S1 to further twist along the N···N axis, resulting in a twisted high-strain conformation. The greater Stokes shift of the more steric-hindered structure can be attributed to the release of larger strain and aromatic stabilization energy. This research highlighted the potential promise associated with the interplay of steric effects and aromaticity reversals in a single fluorophore.

Pancreatic cancer-associated diabetes mellitus is characterized by reduced ß-cell secretory capacity, rather than insulin resistance.

AIMS: The early distinction of pancreatic cancer associated diabetes (PaCDM) in patients with elderly diabetes is critical. However, PaCDM and type 2 diabetes mellitus (T2DM) remain indistinguishable. We aim to address the differences between the pancreatic and gut endocrine hormones of patients with PaCDM and T2DM. METHODS: A total of 44 participants underwent mixed meal tolerance test (MMTT). Fasting and postprandial concentrations of insulin, C-peptide, glucagon, pancreatic polypeptide (PP), glucagon-like peptide-1 (GLP-1), and gastric inhibitory peptide (GIP) were measured. Insulin sensitivity and secretion indices were calculated. One-way ANOVA with post-hoc analysis was used for statistical analysis. RESULTS: Insulin and C-peptide responses to MMTT were blunted in PaCDM patients compared with T2DM. Baseline concentrations and AUCs differed. PaCDM patients showed lower insulin secretion capacity but better insulin sensitivity than T2DM patients. The peak concentration and AUC of PP in T2DM group were higher than healthy controls, but in accordance with PaCDM. PaCDM patients presented lower baseline GLP-1 concentration than T2DM patients. No between-group differences were found for glucagon and GIP. CONCLUSIONS: PaCDM patients had a lower baseline and postprandial insulin and C-peptide secretion than T2DM patients. Reduced insulin secretion and improved peripheral sensitivity were found in PaCDM patients compared with T2DM.

Postoperative exercise training improves the quality of life in patients receiving pulmonary resection: A systematic review and meta-analysis based on randomized controlled trials.

PURPOSE: To evaluate whether postoperative exercise training is effective in improving clinical outcomes such as the quality of life (QoL), exercise capacity and respiratory function of patients receiving pulmonary resection. DATA SOURCES: The PubMed, EMBASE, Web of Science and PEDro electronic databases were comprehensively searched to identify eligible randomized controlled trials (RCTs). METHODS: The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. The primary outcome was postoperative QoL and secondary outcomes were exercise capacity and respiratory function. RESULTS: A total of eight studies involving 691 participants were enrolled in this systematic review and meta-analysis. For the postoperative QoL measured by 36-Item Short Form Health Survey (SF-36), the pooled results demonstrated that postoperative exercise training could significantly improve the SF-36 physical domain score [weighted mean difference (WMD) = 5.87, 95% confidence interval (CI): 3.96 to 7.78, P＜0.001] and SF-36 mental domain score (WMD = 8.15, 95% CI: 0.13 to 16.16, P = 0.05). The results of further analysis for the eight dimensions of SF-36 were similar to the overall results. However, for secondary outcomes, no significant effects of postoperative exercise training on exercise capacity and respiratory function were observed. CONCLUSION: Postoperative exercise training could significantly improve the QoL of patients undergoing lung surgery. However, more RCTs with large samples are still needed to verify the effects of postoperative exercise rehabilitation on clinical outcomes of patients who receive pulmonary resection.

Pancreatic and gut hormone responses to mixed meal test in post-chronic pancreatitis diabetes mellitus.

OBJECTIVE: More than one-third of chronic pancreatitis patients will eventually develop diabetes, recently classified as post-chronic pancreatitis diabetes mellitus (PPDM-C). This study was aimed to investigate the pancreatic and gut hormone responses to a mixed meal test in PPDM-C patients, compared with non-diabetic chronic pancreatitis (CP), and type 2 diabetes patients or healthy controls. DESIGN AND METHODS: Sixteen patients with PPDM-C, 12 with non-diabetic CP as well as 10 with type 2 diabetes and healthy controls were recruited. All participants underwent mixed meal tests, and blood samples were collected for measurements of blood glucose, C-peptide, insulin, glucagon, pancreatic polypeptide (PP), ghrelin, peptide YY, glucagon like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP). Indices of insulin sensitivity and secretion were calculated. Repeated measures analysis of variance was performed. RESULTS: Participants with PPDM-C exhibited decreases in both fasting and postprandial responses of C-peptide (P < 0.001), insulin (P < 0.001), ghrelin (P < 0.001) and PYY (P = 0.006) compared to participants with type 2 diabetes and healthy controls. Patients with CP showed blunted glucagon, PP and incretin reactions, while the responses were increased in patients with PPDM-C compared to controls. The level of insulin sensitivity was higher for PPDM-C than type 2 diabetes (P < 0.01), however the indices for early/late-phase and overall insulin secretion (P < 0.01) were lower. CONCLUSIONS: Patients with PPDM-C are characterized by decreased C-peptide, insulin, ghrelin and PYY responses, and similar levels of glucagon, PP, GIP and GLP-1 compared to those with type 2 diabetes. The above findings, when confirmed in a larger population, may prove helpful to establish the diagnosis of PPDM-C, and should promote study on underlying pathophysiological mechanisms.

Value of Peak Expiratory Flow Rate in Evaluating Cough Ability in Patients Undergoing Lung Surgery.

Introduction: Postoperative ineffective cough is easy to occur after thoracic surgery, and it is also a risk factor for postoperative pulmonary complications (PPCs). Objectives: To explore the value of peak expiratory flow rate (PEF) in evaluating cough ability in patients undergoing lung surgery and evaluate the effectiveness of chest wall compression during the expiratory phase by PEF. Methods: From September 2020 to May 2021, the researchers collected the data of patients who underwent lung surgery. Eventually, 153 patients who met the criteria were included, 102 cases were included in the effective cough group and 51 cases were included in the ineffective cough group. The receiver working curve (ROC curve) was used to analyze whether PEF could evaluate cough ability. At the same time, the researchers collected the pulmonary function data of the first 30 patients of the ineffective cough group while compressing the chest wall during the expiratory phase to evaluate the effectiveness of chest wall compression. Results: The area under the curve (AUC) of postoperative PEF to evaluate the postoperative cough ability was 0.955 (95% CI: 0.927-0.983, P < 0.001). The values of PEF (127.17 ± 34.72 L/min vs. 100.70 ± 29.98 L/min, P < 0.001, 95% CI: 18.34-34.59) and FEV1 (0.72 (0.68-0.97) L vs. 0.64 (0.56-0.82) L, P < 0.001) measured while compressing the chest wall were higher than those without compression. Conclusions: PEF can be used as a quantitative indicator of cough ability. Chest wall compression could improve cough ability for patients who have ineffective cough.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles Promote the Proliferation of Schwann Cells by Regulating the PI3K/AKT Signaling Pathway via Transferring miR-21.

As an alternative mesenchymal stem cell- (MSC-) based therapy, MSC-derived extracellular vesicles (EVs) have shown promise in the field of regenerative medicine. We previously found that human umbilical cord mesenchymal stem cell-derived EVs (hUCMSC-EVs) improved functional recovery and nerve regeneration in a rat model of sciatic nerve transection. However, the underlying mechanisms are poorly understood. Here, we demonstrated for the first time that hUCMSC-EVs promoted the proliferation of Schwann cells by activating the PI3K/AKT signaling pathway. Furthermore, we showed that hUCMSC-EVs mediated Schwann cell proliferation via transfer of miR-21. Our findings highlight a novel mechanism of hUCMSC-EVs in treating peripheral nerve injury and suggest that hUCMSC-EVs may be an attractive option for clinical application in the treatment of peripheral nerve injury.

Combination of Two Colorless Fluorophores for Full-Color Red-Green-Blue Luminescence.

Herein, a molecular pixel system for full-color luminescence reproduction is achieved by adjusting the colorless mixtures of two matching fluorophores, i.e., polarity-insensitive 9,14-diphenyl-9,14-dihydrodibenzo[a,c]phenazine (DPAC) as the fixed red primary color and polarity-sensitive dansylamide (DSA) as dynamic blue to green primary colors. DPAC and DSA possess independent emission properties free from electron and energy transfer crosstalk between them because of their close frontier molecular orbitals as well as similar absorptions below 400 nm. According to the additive color theory, under diverse mixing ratios and various polarities, a smooth emission color change is realized in the triangle surrounded by the luminophores in the chromaticity diagram with accurate prediction and expedient reproduction. The principle of this system may open an innovative route for the development of powerful full-color luminescent materials, for example, ratiometric fluorescent polarity sensors and invisible fluorescent crayons.