Acceptor Framework Research Articles

Steric effects and electronic manipulation of multiple donors on S0/S1 transition of Dn-A emitters

Multiple donor-acceptor (D-A) combinations represent a promising category of thermally activated delayed fluorescence (TADF) materials, offering potential for superior efficiency and stability. However, current systems are predominantly composed of limited donor groups, primarily carbazole-based derivatives. In this work, we developed a series of D-A type materials incorporating helical π-expanded carbazole (CzNaph) and 7H-dinaphtho[1,8-bc:1′,8′-ef]azepine (AzNaph), alongside traditional carbazole, ranging from mono- to tetra-substituted configurations (Dn-A). Through systematic investigation of geometric and electronic structures, the number and positioning of multiple donors are confirmed with significant manipulations on charge transfer characteristics and the S1 state via steric effects. Density functional theory (DFT) calculations reveal that varying the number of π-extended donors within the acceptor framework produces emission colors from ultraviolet to red, providing a diverse range of emitters. Furthermore, the reduced reorganization energy of S1 observed in tetra-substituted Cz and CzNaph, as well as MonoAzN, indicates lower structural relaxation, highlighting these materials' potential as stable luminescent candidates. This study underscores the importance of diverse composing units in achieving efficient and stable TADF emitters with multiple and hetero-donor configurations.

Enhancing Donor–Acceptor Interaction and Framework Stability by the Povarov Reaction for Photocatalytic H2O2 Production

Enhancing Donor–Acceptor Interaction and Framework Stability by the Povarov Reaction for Photocatalytic H₂O₂ Production

Aggregation-induced emission switch showing high contrast mehanofluorochromism and solvatofluorochromism: Specifically detects HSO3− in bioimaging studies

In this work, a novel mechanoresponsive luminescent (MRL) and aggregation induced emission (AIE) switch, 2-(4-((9-butyl-9H-carbazol-3-yl)ethynyl)benzylidene)malononitrile (CABM) has been synthesized by a perfect blending of the carbazole-based triple bond and benzyl malononitrile conjugated derivative via the ‘sonogashira coupling reaction’. The optoelectronic properties of this donor–π–acceptor (D–π–A) framework spontaneously originates a prominent yellow fluorescence which further exhibits a mechanical stimuli induced orange – red emission. Interestingly, just after fumed with dichloromethane (DCM) vapor, the rubbed CABM powder facilely exhibits a restoration in the emission profile as well as fluorescence color. Moreover, this multidimensional switch, CABM shows a prominent solvent dependent sensitivity towards different polarities of organic solvents. CABM also exhibits a typical intramolecular charge transfer (ICT) mechanism along with AIE behaviors with high solid-state efficiency. Importantly, CABM acts as a fluorescence indicator for the qualitative and quantitative detection of low-level water content as impurity in organic solvent. CABM is also found to specifically sense HSO3− anion compared to other guest anions. These promising observations inspire us for the bioimaging studies by using human blood cells which clearly exhibit that CABM can be used to detect HSO3− in human peripheral blood mononuclear cells (PBMCs).

Nonlinear optical properties of superalkali@teetotum boron clusters with potential applications on the electro-optic modulator

The development of nonlinear optics has revolutionized the photonic and optoelectronic fields in recent years.In this paper, we have designed a new class of donor–acceptor frameworks with enhanced nonlinear optical (NLO)properties using a series of superalkalis including Li3O, Li2NaO, LiNa2O, Li2KO, LiK2O as donors and three sizes of teetotum boron clusters (B14, B18, and B22) as acceptors. A systematic first-principles study has been performed on the electronic, linear, and NLO properties of superalkali@Bnassemblies. Besides the static non-linearity, the frequency-dependent electro-optic Pockel's effect (EOPE), second harmonic generation (SHG), and nonlinear refractive index have also been evaluated. In the case of dynamic NLO, the SHG process has a stronger NLO response than EOPE. At the typical experimental frequency of the Nd:YAG laser (ω = 0.04282) a.u., the SHG coefficients are about 2–3 times larger than the corresponding EOPE at this wavelength. Also, the nonlinear refractive index shows a remarkable response atω = 0.04 a.u. for LiK2O@B14.

A double-cable Y-series-based polymer acceptor for efficient all-polymer solar cells: a new strategy of polymerizing small molecule acceptors

In this work, we report a new design strategy to synthesize a double-cable polymer acceptor PT-BTP composed of a fused-ring Y-series acceptor framework as a pendant side unit and thiophene derivative as the conjugated backbone.

A TADF Emitter with Dual Para-Positioned Donors Enables OLEDs with Improved Efficiency and CIE Coordinates Close to the Rec. 2020 Red Standard

Developing red thermally activated delayed fluorescence (TADF) emitters concurrently with high efficiency and emission color close to the BT.2020 red standard is an ongoing challenge. Herein, we developed a new red TADF emitter BCN-TPA, in which two identical donors are attached at the para-positions of one fused phenyl ring in the acceptor framework. Such an arrangement mode can lead the donors with an obvious superimposed effect comparing the conventional arrangement with edge-capped donors on the acceptor. Thus, BCN-TPA yields enhanced overall donor strength with numerous superiorities, such as high oscillator strength and narrow singlet-triplet energy difference, thus giving rise to red-shifted emission with improved overall exciton utilization. In an organic light-emitting diode, BCN-TPA presents efficient deep-red electroluminescence with a maximum external quantum efficiency of 27.6% and a peak at 656 nm, corresponding to CIE coordinates of (0.686, 0.304), which are very close to the red primary in the BT.2020 standard. To the best of our knowledge, this is one of the topmost efficiencies in the field of deep-red TADF OLEDs. This work exemplifies an easy design principle for constructing high-performance deep-red TADF emitters, providing unique molecular-level insights toward improving color quality and elevating efficiency based on conventional D-A type molecular frameworks.

Theoretical study of electronic and nonlinear optical properties of novel graphenylene-based materials with donor-acceptor frameworks.

A new functionalized graphenylene-based structure was designed by adsorbing of alkali metals M3 and superalkali M3O (M = Li, Na, K) on graphenylene (BPC) surface. The spectral data show that the spectral properties of the M3O@BPC system are very similar because the two-dimensional material plays a major role in the main transition. However, for M3@BPC system, the spectral shapes of the three systems show significant changes compared to each other because the different alkali metals play a major role in the main transition process. The calculation results show that the introduction of superalkali does not significantly increase the first polarizability; however, the introduction of alkali metals can obtain considerable nonlinear optical materials. For M3@BPC system, the first hyperpolarizability increases significantly when heavier alkali metal is introduced into the two-dimensional structure, which is found to be 866,290.9 au for K3@ BPC. A two-level model and first hyperpolarizability density can explain the large first polarizability of these systems.

Nearly 100% exciton utilization in highly efficient red OLEDs based on dibenzothioxanthone acceptor

Improving the utilization of excitons has always been an important topic for the development of electroluminescence devices. In this work, we designed and synthesized three red TADF emitters TPA-DBT12, TPA-DBT3 and DTPA-DBT by employing dibenzothioxanthone (DBT) acceptor framework to stabilize the locally excited triplet state to participate in the reverse intersystem crossing (RISC) process. The fast RISC process and singlet radiation decay process gave rise to evidently enhanced exciton utilization. All of the red OLEDs based on these materials showed maximum EQE over 11% and high exciton utilization close to 100%. This work not only extend the acceptor framework for red materials but also provide a new perspective for the design of highly efficient red TADF materials with 100% exciton utilization by managing locally excited triplet state.

Novel Donor–Electret–Acceptor Framework for Higher Charge Transfer and Distance of Charge Transfer through Dipole Engineering

Novel Donor–Electret–Acceptor Framework for Higher Charge Transfer and Distance of Charge Transfer through Dipole Engineering

Decorating electron redundant Si n Al12–n N12 (n = 1, 2) nanocages with superalkalis M3O (M = Li, Na, K): excess electron D-A frameworks and nonlinear optical properties

The electron redundant Si n Al12–n N12 (n = 1, 2) nanocages decorated with superalkalis M3O (M = Li, Na, K) are designed and their stabilities, electronic structures and nonlinear optical (NLO) properties are investigated by using density functional theory calculations. The Si-doped Si n Al12–n N12 cages are more stable than the stoichiometric Al12N12, and the calculation reveals that superalkalis M3O can be bound strongly on these electron redundant cages, with binding energies about 5 eV. The superalkalis M3O transfer electrons to Si n Al12–n N12 and the M3O@Si n Al12–n N12 form excess electron donor–acceptor (eeD-A) frameworks. The excess electrons in M3O@Si n Al12–n N12 form loosely bound lone pair electrons, which push up the HOMO energies and lead to narrower energy gaps. The special electronic structures make these complexes have high NLO responses and they are nearly transparent in deep-ultraviolet region. The largest first hyperpolarisability is observed for K3O@Si2Al10N12 and the value reaches 7.12 × 105 au. We hope this study can provide new strategies for exploring unconventional NLO materials.

Effective rational humanization of a PASylated anti-galectin-3 Fab for the sensitive PET imaging of thyroid cancer in vivo

The lack of a non-invasive test for malignant thyroid nodules makes the diagnosis of thyroid cancer (TC) challenging. Human galectin-3 (hGal3) has emerged as a promising target for medical TC imaging and diagnosis because of its exclusive overexpression in malignant thyroid tissues. We previously developed a human-chimeric αhGal3 Fab fragment derived from the rat monoclonal antibody (mAb) M3/38 with optimized clearance characteristics using PASylation technology. Here, we describe the elucidation of the hGal3 epitope recognized by mAb M3/38, X-ray crystallographic analysis of its complex with the chimeric Fab and, based on the three-dimensional structure, the rational humanization of the Fab by CDR grafting. Four CDR-grafted versions were designed using structurally most closely related fully human immunoglobulin VH/VL regions of which one—employing the acceptor framework regions of the HIV-1 neutralizing human antibody m66—showed the highest antigen affinity. By introducing two additional back-mutations to the rodent donor sequence, an affinity toward hGal3 indistinguishable from the chimeric Fab was achieved (KD = 0.34 ± 0.02 nM in SPR). The PASylated humanized Fab was site-specifically labelled with the fluorescent dye Cy7 and applied for the immuno-histochemical staining of human tissue sections representative for different TCs. The same protein was conjugated with the metal chelator Dfo, followed by radiolabelling with 89Zr(IV). The resulting protein tracer allowed the highly sensitive and specific PET/CT imaging of orthotopic tumors in mice, which was confirmed by quantitative analysis of radiotracer accumulation. Thus, the PASylated humanized αhGal3 Fab offers clinical potential for the diagnostic imaging of TC.

A unique self-reporting photosensitizer enabling simultaneous photodynamic therapy and real-time monitoring of phototheranostic process in a dynamic dual-color mode.

Phototheranostics has attracted great interest in cancer therapy. Small-molecule self-reporting photosensitizers, one kind of idea agent in phototheranostics, enables simultaneous photodynamic therapy (PDT) and feedback of therapeutic efficacy. However, previous such photosensitizers exclusively employed the change of single emission to monitor cell death, which can be disturbed by variations in photosensitizer concentration and the excitation intensity. Herein, we report a unique self-reporting photosensitizer TPA-3PyA+ constructed from a twisted triphenylamine unit (TPA), three benzene ring units and three cyanovinyl-pyridinium units (PyA) for PDT and its real-time monitoring in a dynamic dual-color mode. TPA-3PyA+ possesses a rotatable electron donor-π bridge-electron acceptor framework and exhibits high singlet oxygen quantum yield (124%) and a twisted intramolecular charge transfer (TICT) effect. TPA-3PyA+ not only enables effective staining of cancer cells with dual-color fluorescence due to the TICT effect but also shows excellent PDT performance. The simultaneous change in emission color, intensity and intracellular location of TPA-3PyA+ during cell death allows it to self-report cell death. Moreover, the change of dual-emission color allows distinguishing living and dead cells and effectively avoids interference in previous single-emission self-reporting photosensitizers. This work highlights the great potential of a self-reporting photosensitizer with dual-color emissions for efficient feedback of theranostics.

Humanization of Chicken‐Derived scFv Using Yeast Surface Display and NGS Data Mining

Generation of high-affinity monoclonal antibodies by immunization of chickens is a valuable strategy, particularly for obtaining antibodies directed against epitopes that are conserved in mammals. A generic procedure is established for the humanization of chicken-derived antibodies. To this end, high-affinity binders of the epidermal growth factor receptor extracellular domain are isolated from immunized chickens using yeast surface display. Complementarity determining regions (CDRs) of two high-affinity binders are grafted onto a human acceptor framework. Simultaneously, Vernier zone residues, responsible for spatial CDR arrangement, are partially randomized. A yeast surface display library comprising ≈300 000 variants is screened for high-affinity binders in the scFv and Fab formats. Next-generation sequencing discloses humanized antibody variants with restored affinity and improved protein characteristics compared to the parental chicken antibodies. Furthermore, the sequencing data give new insights into the importance of antibody format, used during the humanization process. Starting from the antibody repertoire of immunized chickens, this work features an effective and fast high-throughput approach for the generation of multiple humanized antibodies with potential therapeutic relevance.

Therapeutic efficacy of a novel humanized antibody-drug conjugate recognizing plexin-semaphorin-integrin domain in the RON receptor for targeted cancer therapy

BackgroundAntibody-drug conjugates (ADCs) targeting the RON receptor, a tumorigenic factor contributing to cancer malignancy, has been considered as a novel strategy for cancer therapy. Here we describe a humanized antibody recognizing the RON plexin-semaphorin-integrin (PSI) domain with increased drug delivery capability for potential clinical application.MethodMonoclonal antibody PCM5B14 specific to the human and monkey RON PSI domain was generated and characterized by various immunological methods. Humanized antibody H5B14 was created by grafting PCM5B14 complementarity-determining regions into human IgG1/κ acceptor frameworks and conjugated with monomethyl auristatin E and duocarmycin to form two H5B14-based ADCs. Stability of H5B14-based ADCs in human plasma was measured using hydrophobic interaction chromatography. Various biochemical and biological assays were used to determine ADC- regulated RON internalization, cell viability, spheroid formation, and death of cancer stem-like cells. Efficacies of H5B14-based ADCs in vivo were validated using tumor xenograft models. Maximal tolerated doses of H5B14-based ADCs were established in mice.ResultsH5B14 was highly specific to the human RON PSI domain and superior over other anti-RON ADCs in induction of RON internalization in various cancer cell lines tested. H5B14-based ADCS had a drug to antibody ratio of ~ 3.70:1 and were stable in human plasma with a minimal dissociation within a 10-day period. Functionally, H5B14-mediated drug delivery decreased cell viability at early stages with an average IC50 at ~ 20 nM in multiple cancer cell lines examined. H5B14-based ADCs also inhibited spheroid formation and caused death of cancer stem-like cells with RON+/CD44+/ESA+ phenotypes. In vivo, H5B14-based ADCs in a single injection inhibited tumor xenograft growth mediated by multiple cancer cell lines. Tumoristatic concentrations calculated from xenograft tumor models were in the range of 0.63 to 2.0 mg/kg bodyweight. Significantly, H5B14-based ADCs were capable of eradicating tumors at variable levels across multiple xenograft models regardless their malignant statuses. Toxicologically, H5B14-based ADCs were well tolerated in mice up to 60 mg/kg.ConclusionH5B14-based ADCs targeting the RON PSI domain are superior in inducing RON internalization, leading to robust drug delivery and overall inhibition and eradication of tumors in multiple xenograft models. These findings warrant H5B14-based ADCs for clinical trials in the future.

Superalkali–Superhalogen Complexes as Versatile Materials for Hydrogen Storage: A Theoretical Study

In the present work, we have studied superhalogen (Al13)–superalkali (M3O, M = Li, Na, and K) assemblages as versatile materials for hydrogen storage. In the present study, we suggest an interesting material to form a sets of typical donor–acceptor frameworks with high hydrogen storage performance via linking the superalkalis M3O to the superhalogen Al13. Our density functional theory (DFT) calculations reveal that the band gap energy of Al13 is decreased by attaching of the M3O superalkalis. Also, we found that the M3O species lowered the band gap energy of Al13 by more than 32% and converted it to an n-type semiconductor. Hydrogen adsorption on Al13–M3O (M = Li, Na, and K) is explored by DFT calculations and the results are compared with the hydrogen adsorption on the Al13–M (Li, Na, and K) systems. We found that the Al13–M3O systems show higher hydrogen storage performance as compared to the Al13–M systems. In fact, the Al13–M3O with three alkali metals show high-capacity hydrogen storage than the Al13–M systems. Among the six Al13–M and Al13–M3O systems, the maximum adsorption energy and the higher capacity hydrogen storage is related to the hydrogen adsorption on the Al13–Li3O. Our study exhibits that the Al13–Li3O is a promising material for hydrogen storage.

Theoretical study on design of novel superalkalis doped graphdiyne: A new donor–acceptor (D-π-A) strategy for enhancing NLO response

Abstract Based on DFT calculations, we designed a new series of superalkali doped graphdiyne (GDY) complexes, M2X@GDY (M = Li, Na, K and X = F, Cl, Br) having electron donor and acceptor (D-π-A) framework. Our results of interaction energies reveal that these superalkalis are quite stable and chemisorbed over the 18 membered site of GDY. DFT results also reveal that the doping of superalkalis on GDY leads to narrowing of the HOMO-LUMO gaps, which enhance their conductance properties. Furthermore, the polarizability and first hyperpolarizability of GDY are enhanced dramatically up to 7.7 × 104 au. The enhanced first hyperpolarizabilities are further explained by two level model expression from TD-DFT calculations. The TD-DFT results show that all these designed superalkali doped graphdiyne complexes have ultraviolet light transparency. To rationalize the hyperpolarizability trend in superalkali doped GDY complexes, βvec calculations are also performed. This study may provide better understanding for the direct synthesis of new GDY based NLO materials in industries.

Design of a novel series of small molecule donors for application in organic solar cells

In an effort to study high-efficient electron donor materials for application in organic solar cells (OSC), density functional theory (DFT) calculations were performed to predict a variety of small molecules (SMs) with terminal acceptor-π bridge-central donor-π bridge-terminal acceptor (A-π-D-π-A) framework. An interesting A-π-D-π-A-type SM containing phenothiazine as D unit has been recently synthesized and applied to in the OSC. Motivated by this study, here, we have systematically predicted 10 SM donor materials based on the phenothiazine as the central D unit as well as several A and π units that have been used into materials representing excellent SC as well as charge transport characteristics. Then, the structural, electronic, and optical properties of the predicted SM donors have been investigated. The fundamental band gap energies, orbital spatial distributions, and intrinsic dipole moments were calculated using DFT while the optical band gap energies were obtained using time-dependent density functional theory (TD-DFT). Several SC properties of the predicted SMs were then computed and compared with the available experimental results of OSCs. Our suggested SMs represented the enhancement in the open circuit voltage (VOC) and charge transport properties which may lead to OSCs with improved power conversion efficiency (PCE) compared to the previously synthesized SMs. Moreover, small reorganization energies, large transfer integrals, and high intra-molecular coupling obtained from dense π-stacking give rise to increased electron mobility in the predicted SMs. However, this strategy can be helpful for further improving the performance of SMs in OSCs.

Therapeutic efficacy, pharmacokinetic profiles, and toxicological activities of humanized antibody-drug conjugate Zt/g4-MMAE targeting RON receptor tyrosine kinase for cancer therapy

BackgroundAberrant expression of the RON receptor tyrosine kinase is a pathogenic feature and a validated drug target in various types of cancers. Currently, therapeutic antibodies targeting RON for cancer therapy are under intensive evaluation. Here we report the development and validation of a novel humanized anti-RON antibody-drug conjugate for cancer therapy.MethodsAntibody humanization was achieved by grafting sequences of complementarity-determining regions from mouse monoclonal antibody Zt/g4 into human IgG1/κ acceptor frameworks. The selected humanized Zt/g4 subclone H1L3 was conjugated with monomethyl auristatin E using a dipeptide linker to form H-Zt/g4-MMAE. Pharmacokinetic analysis of H-Zt/g4-MMAE was determined using hydrophobic interaction chromatography and a MMAE ADC ELISA kit. Biochemical and biological assays were used for measuring RON expression, internalization, cell viability and death. Therapeutic efficacies of H-Zt/g4-MMAE were validated in vivo using three pancreatic cancer xenograft models. Toxicological activities of H-Zt/g4-MMAE were determined in mouse and cynomolgus monkey.ResultsH-Zt/g4-MMAE had a drug to antibody ratio of 3.77:1 and was highly stable in human plasma with a dissociation rate less than 5% within a 20 day period. H-Zt/g4-MMAE displayed a favorable pharmacokinetic profile in both mouse and cynomolgus monkey. In vitro, H-Zt/g4-MMAE induced RON internalization, which results in killing of pancreatic cancer cells with IC50 values at 10–20 nM. In vivo, H-Zt/g4-MMAE inhibited pancreatic cancer xenograft growth with tumoristatic concentrations at 1~3 mg/kg bodyweight. Significantly, H-Zt/g4-MMAE eradicated tumors across multiple xenograft models regardless their chemoresistant and metastatic statuses. Moreover, H-Zt/g4-MMAE inhibited and eradicated xenografts mediated by pancreatic cancer stem-like cells and by primary cells from patient-derived tumors. Toxicologically, H-Zt/g4-MMAE is well tolerated in mice up to 60 mg/kg. In cynomolgus monkey, H-Zt/g4-MMAE up to 30 mg/kg had a manageable and reversible toxicity profile.ConclusionsH-Zt/g4-MMAE is superior in eradication of pancreatic cancer xenografts with favorable pharmacokinetic profiles and manageable toxicological activities. These findings warrant the transition of H-Zt/g4-MMAE into clinical trials in the future.

Synthesis of dipyrrolopyrazine-based sensitizers with a new π-bridge end-capped donor–acceptor framework for DSSCs: a combined experimental and theoretical investigation

Organic dyes with dipyrrolopyrazine as the central π-linker have been synthesized. Photovoltaic properties were investigated and supported by DFT. Thermal analysis shows good thermal stability.

Rational design of high efficiency green to deep red/near-infrared emitting materials based on isomeric donor–acceptor chromophores

A family of chromophores with an isomeric donor–acceptor framework are synthesized, which show remarkably different emission wavelengths with high photoluminescence quantum yields and decent electroluminescent efficiencies.