A unified evaluation descriptor for π-bridges applied to metalloporphyrin derivatives.

Establishing the structure of porphyrins with a A-π-D-π-A configuration is one of the effective strategies to maintain their dominance and compensate shortcomings through flexible changes in fragments. In this regard, π-bridges have attracted wide attention as a parameter affecting molecular backbones, electron transfer, energy levels, absorption, and other properties. However, the essence and influence of π-bridges have not yet been confirmed. In order to satisfy the requirements of intelligent application in molecular design, this study aimed to investigate the control effect of differences in π-bridge composition (thiophene and selenophene) and connection type (single bonds, ethylenic bonds and fused) on photoelectric performance. Y6 and PC61BM were used as acceptors to build donor/acceptor (D/A) interfaces and characterize the film morphology in three dimensions. Results showed that the essence of π-bridges involves a strong bridging effect (adjusting ability) between A and D fragments rather than highlighting its own nature. The large value could obtain high open circuit voltages (VOC), large separation and small recombination rates as well as stable and tight morphology. Therefore, adjusting ability is a unified descriptor for evaluating π-bridges, and it is an effective strategy to adjust material properties and morphology. This insight and discovery may provide a new evaluation descriptor for the screening and design of π-bridges.

Exogenous Hemin alleviates cadmium stress in maize by enhancing sucrose and nitrogen metabolism and regulating endogenous hormones.

Cadmium (Cd) stress restricts maize growth and productivity severely. We aimed to investigate the effects of Hemin on the metabolism of sucrose and nitrogen and endogenous hormones in maize under cadmium stress. Maize varieties 'Tiannong 9' (cadmium tolerant) and 'Fenghe 6' (cadmium sensitive) were grown in nutrient solutions to study the effects of Hemin on maize physiological and ecological mechanisms under cadmium stress. The results showed that Hemin mediated the increase of sucrose content and the activities of key enzymes sucrose phosphate synthase (SPS) and sucrose synthase (SS) in maize leaves under cadmium stress. Soluble acid invertase (SAInv) and basic/neutral invertase (A/N-Inv) enzyme activities in leaves were decreased significantly, and sucrose accumulation in leaves was increased. Hemin also mediated the increase of NO3- content in leaves, the decrease of NH4+ content and the increase of nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase activity (GOGAT) and glutamate dehydrogenase (GDH) enzyme activities under cadmium stress. The contents of IAA, ZR, and GA in leaves and roots increased, ABA, MeJA, and SA decreased, and IAA/ABA, ZR/ABA, and GA/ABA increased under cadmium stress. Our study showed Hemin can alleviate cadmium stress in maize by enhancing sucrose and nitrogen metabolism and regulating endogenous hormones.

This work further investigates the effects of Hemin on the metabolism of sucrose and nitrogen and endogenous hormones in maize under cadmium stress, which, hopefully, is to guide Hemin application to maize field resilience production. It also explains that Hemin is beneficial for dry matter accumulation and transport, alleviated ammonia toxicity and nitrogen metabolism disorder, and induced the changes of endogenous hormone content and the adaptive hormone ratio balance under cadmium stress.

Optimal Dihedral Angle in Twisted Donor-Acceptor Organic Emitters for Maximized Thermally Activated Delayed Fluorescence.

The twisted donor-acceptor (D-A) organic formwork with a large dihedral angle (θDA ) is usually adopted to narrow the singlet-triplet energy gap for obtaining excellent thermally activated delayed fluorescence (TADF) emitters. However, the dependence of overall TADF properties on θDA has not been systematically investigated to this day. Taking new designed CzBP, CzBP-1M and CzBP-2M via introducing methyl as investigated models, it is found that (i) with increasing θDA , the charge transfer component in S1 is larger than that in T1 in varying degrees, leading to non-monotonic spin-orbit couplings; (ii) the electron-vibration couplings between S1 and T1 states become the largest when θDA approaching 80°, facilitating phonon-driven up-conversion; (iii) the overall TADF rate reaches a peak at θDA ≈80°. By this, the TADF on/off switching is realized via methyl moiety for regulating θDA from theoretical prediction to experimental confirmation. Importantly, the θDA near 80° would be a good descriptor for screening excellent D-A type TADF emitters.

The mechanism of the selective binding ability between opiate metabolites and acyclic cucurbit[4]uril: an MD/DFT study.

Subtle changes in molecular structure often lead to significant differences in host-guest interactions, which result in different host-guest recognition capabilities and dynamics behaviours in complex formation. Herein, we reveal the influence of the guest substituents on host-guest molecular recognition by molecular dynamics (MD) simulation and density functional theory (DFT) approaches. The results suggest that the binding energy barrier of acyclic cucurbit[4]uril (ACB[4]) with opiate metabolites gradually decreases. The methyl group in morphine (MOR) and morphine-3-glucuronide (M3G) strengthens the hydrophobicity of the guest, while depressing the energy loss of the desolvation of polar groups (e.g. hydroxyl) inside the ACB[4] cavity. However, in M3G, the 3-glucuronide group located outside the ACB[4] host cavity effectively alleviates the unfavourable desolvation effect of the hydroxyl and increases the binding constant by two orders of magnitude (compared with normorphine (NMOR)). Our findings stressed the essentiality of the binding mode and intermolecular noncovalent interactions in the host-guest selective binding ability.

Revealing the reason for the reversal of properties from fullerene to nonfullerene.

The existence of an inflection point between fullerene and nonfullerene molecules was demonstrated using bowl-nonfullerene models, which were proposed to explore the key points relating to the different properties. This study explains the differences in the stacking configurations of the inflection points and reveals the reason for the inversion of properties, which is caused by small structural differences.

Design of single-porphyrin donors toward high open-circuit voltage for organic solar cells via an energy level gradient-distribution screening strategy of fragments: a theoretical study.

Open-circuit voltage (VOC) is a key factor for improving the power conversion efficiency (PCE) of bulk heterojunction (BHJ) organic solar cells (OSCs). At present, increasing attention has been devoted towards modifying π bridges in single-porphyrin small molecule donors with an A-π-D-π-A configuration to reduce the highest occupied molecular orbital (HOMO) levels and improve the VOC of devices. However, how to screen the π bridges is a key issue. In this work, nine π bridges were screened by the HOMO level gradient-distribution strategy of fragments (electron-donating donor (D), π bridges, and electron-withdrawing acceptor (A)), where fragments meeting the requirements were combined into five novel small molecule donors. Meanwhile, in order to test whether the strategy is beneficial to increasing VOC, [6,6]-phenyl C61-butyric acid methyl ester (PC61BM) was selected as the acceptor material. The energy levels of all molecules were compared and the photoelectric properties (i.e., energy gap, energy driving force, reorganization energy, intermolecular charge transfer rate, charge recombination rate, and VOC) of the five small molecules were studied. The results showed that the HOMO levels of porphyrin donors could be significantly lowered via this strategy, and VOC was raised without losing the short-circuit current (JSC) and fill factor (FF) of the devices. Meanwhile, the designed five small molecules could be used as donor candidates to improve the performance of OSCs.

Suppression of WHITE COLLAR-independent frequency Transcription by Histone H3 Lysine 36 Methyltransferase SET-2 Is Necessary for Clock Function in Neurospora.

The circadian system in Neurospora is based on the transcriptional/translational feedback loops and rhythmic frequency (frq) transcription requires the WHITE COLLAR (WC) complex. Our previous paper has shown that frq could be transcribed in a WC-independent pathway in a strain lacking the histone H3K36 methyltransferase, SET-2 (su(var)3-9-enhancer-of-zeste-trithorax-2) (1), but the mechanism was unclear. Here we disclose that loss of histone H3K36 methylation, due to either deletion of SET-2 or H3K36R mutation, results in arrhythmic frq transcription and loss of overt rhythmicity. Histone acetylation at frq locus increases in set-2(KO) mutant. Consistent with these results, loss of H3K36 methylation readers, histone deacetylase RPD-3 (reduced potassium dependence 3) or EAF-3 (essential SAS-related acetyltransferase-associated factor 3), also leads to hyperacetylation of histone at frq locus and WC-independent frq expression, suggesting that proper chromatin modification at frq locus is required for circadian clock operation. Furthermore, a mutant strain with three amino acid substitutions (histone H3 lysine 9, 14, and 18 to glutamine) was generated to mimic the strain with hyperacetylation state of histone H3. H3K9QK14QK18Q mutant exhibits the same defective clock phenotype as rpd-3(KO) mutant. Our results support a scenario in which H3K36 methylation is required to establish a permissive chromatin state for circadian frq transcription by maintaining proper acetylation status at frq locus.

Theoretical study on the charge transfer mechanism at donor/acceptor interface: Why TTF/TCNQ is inadaptable to photovoltaics?

A combined molecular dynamics (MD) and quantum chemical (QC) simulation method is utilized to investigate charge generation mechanism at TTF/TCNQ (tetrathiafulvalene/tetracyanoquinodimethane) heterojunction, which is a controversial donor/acceptor (D/A) interface for organic photovoltaic (OPV) devices. The TTF/TCNQ complexes extracted from MD simulation are classified into parallel and herringbone packings. And then, the amounts of charge transferred from ground states to different excited states and the corresponding energies of charge transfer (CT) state are compared and analyzed using QC simulation. Moreover, the electron transfer/recombination rates for these interfacial configurations are also studied. From these data, we have elucidated the underlying reason why TTF/TCNQ heterojunction is inadaptable to OPV application. One main reason is that large |ΔGCT| (the absolute value of Gibbs free energy change of CT) forms a large energy barrier, limiting exciton dissociation at the TTF/TCNQ heterojunction, and small |ΔGCR| (the absolute value of Gibbs free energy change of charge recombination) performs the easy recombination to the ground state.

Suppression of WC-independent frequency transcription by RCO-1 is essential for Neurospora circadian clock.

Rhythmic activation and repression of clock gene transcription is essential for the functions of eukaryotic circadian clocks. In the Neurospora circadian oscillator, frequency (frq) transcription requires the WHITE COLLAR (WC) complex. Here, we show that the transcriptional corepressor regulation of conidiation-1 (RCO-1) is essential for clock function by regulating frq transcription. In rco-1 mutants, both overt and molecular rhythms are abolished, frq mRNA levels are constantly high, and WC binding to the frq promoter is dramatically reduced. Surprisingly, frq mRNA levels were constantly high in the rco-1 wc double mutants, indicating that RCO-1 suppresses WC-independent transcription and promotes WC complex binding to the frq promoter. Furthermore, RCO-1 is required for maintaining normal chromatin structure at the frq locus. Deletion of H3K36 methyltransferase su(var)3-9-enhancer-of-zeste-trithorax-2 (SET-2) or the chromatin remodeling factor CHD-1 leads to WC-independent frq transcription and loss of overt rhythms. Together, our results uncover a previously unexpected regulatory mechanism for clock gene transcription.

Histone H3K56 acetylation is required for quelling-induced small RNA production through its role in homologous recombination.

Quelling and DNA damage-induced small RNA (qiRNA) production are RNA interference (RNAi)-related phenomenon from repetitive genomic loci in Neurospora. We have recently proposed that homologous recombination from repetitive DNA loci allows the RNAi pathway to recognize repetitive DNA to produce small RNA. However, the mechanistic detail of this pathway remains largely unclear. By systematically screening the Neurospora knock-out library, we identified RTT109 as a novel component required for small RNA production. RTT109 is a histone acetyltransferase for histone H3 lysine 56 (H3K56) and H3K56 acetylation is essential for the small RNA biogenesis pathway. Furthermore, we showed that RTT109 is required for homologous recombination and H3K56Ac is enriched around double strand break, which overlaps with RAD51 binding. Taken together, our results suggest that H3K56 acetylation is required for small RNA production through its role in homologous recombination.

Poly(aryl ether) Dendrons with Monopyrrolotetrathiafulvalene Unit-Based Organogels exhibiting Gel-Induced Enhanced Emission (GIEE).

A series of poly(aryl ether) dendrons with a monopyrrolo-tetrathiafulvalene unit linked through an acyl hydrazone linkage were designed and synthesized as low molecular mass organogelators (LMOGs). Two of the dendrons could gelate the aromatic solvents and some solvent mixtures, but the others could not gel all solvents tested except for n-pentanol. A subtle change on the molecular structure produces a great influence on the gelation behavior. Note that the dendrons could form the stable gel in the DMSO/water mixture without thermal treatment and could also form the binary gel with fullerene (C60 ) in toluene. The formed gels undergo a reversible gel-sol phase transition upon exposure to external stimuli, such as temperature and chemical oxidation/reduction. A number of experiments (SEM, FTIR spectroscopy, (1) H NMR spectroscopy, and UV/Vis absorption spectroscopy, and XRD) revealed that these dendritic molecules self-assembled into elastically interpenetrating one-dimensional fibrillar aggregates and maintain rectangular molecular-packing mode in organogels. The hydrogen bonding, π-π, and donor-acceptor interactions were found to be the main driving forces for formation of the gels. Moreover, the gel system exhibited gel-induced enhanced emission (GIEE) property in the visible region in spite of the absence of a conventional fluorophore unit and the fluorescence was effectively quenched by introduction of C60 .

Modification of metals and ligands in two-dimensional conjugated metal-organic frameworks for CO2 electroreduction: A combined density functional theory and machine learning study.

Electrochemical carbon dioxide reduction reaction (CO2RR) is a promising technology to establish an artificial carbon cycle. Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) with high electrical conductivity have great potential as catalysts. Herein, we designed a range of 2D c-MOFs with different transition metal atoms and organic ligands, TMNxO4-x-HDQ (TM = Cr∼Cu, Mo, Ru∼Ag, W∼Au; x  = 0, 2, 4; HDQ = hexadipyrazinoquinoxaline), and systematically studied their catalytic performance using density functional theory (DFT). Calculation results indicated that all of TMNxO4-x-HDQ structures possess good thermodynamic and electrochemical stability. Notably, among the examined 37 MOFs, 6 catalysts outperformed the Cu(211) surface in terms of catalytic activity and product selectivity. Specifically, NiN4-HDQ emerged as an exceptional electrocatalyst for CO production in CO2RR, yielding a remarkable low limiting potential (UL) of -0.04 V. CuN4-HDQ, NiN2O2-HDQ, and PtN2O2-HDQ also exhibited high activity for HCOOH production, with UL values of -0.27, -0.29, and -0.27 V, respectively, while MnN4-HDQ, and NiO4-HDQ mainly produced CH4 with UL values of -0.58 and -0.24 V, respectively. Furthermore, these 6 catalysts efficiently suppressed the competitive hydrogen evolution reaction. Machine learning (ML) analysis revealed that the key intrinsic factors influencing CO2RR performance of these 2D c-MOFs include electron affinity (EA), electronegativity (χ), the first ionization energy (Ie), p-band center of the coordinated N/O atom (εp), the radius of metal atom (r), and d-band center (εd). Our findings may provide valuable insights for the exploration of highly active and selective CO2RR electrocatalysts.

A hybridization-induced charge-transfer state energy arrangement reduces nonradiative energy loss in organic solar cells.

Here, we explain why the Energy Gap Law and the energy inversion related to the charge-transfer state have opposite effects on the trend of nonradiative energy loss of organic solar cells. The root is the existing condition of energy inversion. There is indeed a certain probability of energy inversion, but it will eventually be implicit or explicit as determined by the hybridization, which depends on the electron-withdrawing unit of the donor, giving rise to different stacking sites. The triplet-state hybridization leads to an explicit characteristic, while singlet-state hybridization leads to an implicit characteristic.

The Role of Terminal Fluorination on Energy Inversion in Organic Solar Cells.

Suppressing the non-radiative energy loss (ΔE3) mediated by triplet charge transfer state is crucial for high-performance organic solar cells (OSCs). Here, we decode the energy inversion through multi-scale theoretical simulation, which inhibits the non-emissive triplet (T1) state formation. However, it is mystified by the system dependence. We first demonstrate a direct relationship of "the probability of Face-on orientation (PFace-on) is proportional to the probability of energy inversion (PEI)", which is related to the function of terminal fluorination. Through Pearson's correlation coefficient and machine learning model, the useful stacking structural parameters were obtained to clarify the effect of π-bridge group on the function of terminal fluorination. Based on the molecular descriptors established, we explain that the fluorination effect is beneficial to Face-on orientation and thus energy inversion due to the enhanced intermolecular coupling. But the π-bridge inhibits this coupling with the interfacial stacking configuration appearing more "TT_IC". This work provides a directional standard for promoting energy inversion to reduce ΔE3 for the high-performance OSCs.

A sensitive and selective fluorescent probe for cysteine based on a new response-assisted electrostatic attraction strategy: the role of spatial charge configuration.

A new strategy for fast fluorescent detection of cysteine (Cys), based on a response-assisted electrostatic attraction, is demonstrated. By utilizing this strategy, we designed and synthesized three fluorescent probes for the specific detection of Cys under actual physiological conditions. The probe m-CP, a coumarin fluorophore conjugated with a substituted methyl pyridinium group through an unsaturated ketone unit, showed highly selective and sensitive detection for cysteine (Cys) over homocysteine (Hcy) and glutathione (GSH). The kinetic analysis indicated that the sensing process was highly accelerated (a response time less than 1 min) by the response-assisted electrostatic attraction. More importantly, control experiments with isomeric probes first demonstrated that the spatial charge configuration of the probe played an important role in Cys-preferred selectivity and kinetic rate acceleration. Furthermore, the practical utility of the probe m-CP in the fluorescent labeling of Cys residues within proteins was demonstrated. Finally, these probes were employed in living cell imaging with HeLa cells, in which it displayed satisfactory cell permeability and enabled us to distinguish active thiols in the cytoplasm, nucleus, and mitochondria.

Synthesis and properties of T-shaped organic conjugates based on 3,6-diarylpyridazine-fused tetrathiafulvalene.

A facile synthetic approach to the π-expanded tetrathiafulvalene derivatives is described. The Suzuki reaction of 3,6-dichloropyridazine-fused tetrathiafulvalenes with phenyl boronic acid or biphenyl boronic acid gave a series of novel T-shaped organic π-conjugates. The electronic properties of the conjugates were studied experimentally by the combination of cyclic voltammetry and UV-vis spectroscopy. Their HOMO and LUMO energy levels are estimated to be about -5 eV and -3.2 eV, which are the air operating stability ranges in the p-channel and n-channel field effect transistors, respectively. Only one conjugate bearing the longer alkyl chain (n = 1, R = n-C18H37) was verified to self-assemble into lamellar structures in the mesogenic phase and the best measured charge carrier mobility of its thin-film devices was 4.5 × 10(-5) cm(2) V(-1) s(-1).

AMPK Associates with Chromatin and Phosphorylates the TAF-1 Subunit of the Transcription Initiation Complex to Regulate Histone Gene Expression in ALL Cells.

The survival rates for relapsed/refractory acute lymphoblastic leukemia (ALL) remain poor. We and others have reported that ALL cells are vulnerable to conditions inducing energy/ER-stress mediated by AMP-activated protein kinase (AMPK). To identify the target genes directly regulated by AMPKα2, we performed genome-wide RNA-seq and ChIP-seq in CCRF-CEM (T-ALL) cells expressing HA-AMPKα2 (CN2) under normal and energy/metabolic stress conditions. CN2 cells show significantly altered AMPKα2 genomic binding and transcriptomic profile under metabolic stress conditions, including reduced histone gene expression. Proteomic analysis and in vitro kinase assays identified the TATA-Box-Binding Protein-Associated Factor 1 (TAF1) as a novel AMPKα2 substrate that downregulates histone gene transcription in response to energy/metabolic stress. Knockdown and knockout studies demonstrated that both AMPKα2 and TAF1 are required for histone gene expression. Mechanistically, upon activation, AMPKα2 phosphorylates TAF1 at Ser-1353 which impairs TAF1 interaction with RNA polymerase II (Pol II), leading to a compromised state of p-AMPKα2/p-TAF1/Pol II chromatin association and suppression of transcription. This mechanism was also observed in primary ALL cells and in vivo in NSG mice. Consequently, we uncovered a non-canonical function of AMPK that phosphorylates TAF1, both members of a putative chromatin-associated transcription complex that regulate histone gene expression, among others, in response to energy/metabolic stress. IMPLICATIONS: Fully delineating the protein interactome by which AMPK regulates adaptive survival responses to energy/metabolic stress, either via epigenetic gene regulation or other mechanisms, will allow the rational development of strategies to overcome de novo or acquired resistance in ALL and other cancers.

Energy differences as descriptors for the correlation between JSC and VOC in nonfullerene organic photovoltaics.

ITIC-series nonfullerene organic photovoltaics (NF OPVs) have realized the simultaneous increases of the short-circuit current density (JSC) and open-circuit voltage (VOC), called the positive correlation between JSC and VOC, which could improve the power conversion efficiency (PCE). However, it is complicated to predict the formation of positive correlation in devices through simple calculations of single molecules due to their dimensional differences. Here, a series of symmetrical NF acceptors blended with the PBDB-T donor were chosen to establish an association framework between the molecular modification strategy and positive correlation. It can be found that the positive correlation is modification site-dependent following the energy variation at the different levels. Furthermore, to illustrate a positive correlation, the energy gap differences (ΔEg) and the energy level differences of the lowest unoccupied molecular orbitals (ΔELUMO) between the two changed acceptors were proposed as two molecular descriptors. Combined with the machine learning model, the accuracy of the proposed descriptor is more than 70% for predicting the correlation, which verifies the reliability of the prediction model. This work establishes the relative relationship between two molecular descriptors with different molecular modification sites and realizes the prediction of the trend of efficiency. Therefore, future research should focus on the simultaneous enhancement of photovoltaic parameters for high-performance NF OPVs.

Effects of Multi-Walled Carbon Nanotubes and Nano-Silica on Root Development, Leaf Photosynthesis, Active Oxygen and Nitrogen Metabolism in Maize.

Carbon nanotubes (MWCNTs) and nano-silica (nano-SiO2) are widely used in the field of life science because of their special physical and chemical properties. In this study, the effects of different concentrations of MWCNTs (0 mg·L-1, 200 mg·L-1, 400 mg·L-1, 800 mg·L-1 and 1200 mg·L-1) and nano-SiO2 (0 mg·L-1, 150 mg·L-1, 800 mg·L-1, 1500 mg·L-1 and 2500 mg·L-1) on maize seedling growth and relative mechanisms were explored. The main results are as follows: MWCNTs and nano-SiO2 can promote the growth of maize seedlings, and promote plant height, root length, the dry and fresh weight of seedlings, root-shoot ratio and so on. The ability to accumulate dry matter increased, the relative water content of leaves increased, the electrical conductivity of leaves decreased, the stability of cell membranes improved and the water metabolism ability of maize seedlings increased. The treatment of MWCNTs with 800 mg·L-1 and nano-SiO2 with 1500 mg·L-1 had the best effect on seedling growth. MWCNTs and nano-SiO2 can promote the development of root morphology, increase root length, root surface area, average diameter, root volume and total root tip number and improve root activity, so as to improve the absorption capacity of roots to water and nutrition. After MWCNT and nano-SiO2 treatment, compared with the control, the contents of O2·- and H2O2 decreased, and the damage of reactive oxygen free radicals to cells decreased. MWCNTs and nano-SiO2 can promote the clearance of reactive oxygen species and maintain the complete structure of cells, so as to slow down plant aging. The promoting effect of MWCNTs treated with 800 mg·L-1 and nano-SiO2 treated with 1500 mg·L-1 had the best effect. After treatment with MWCNTs and nano-SiO2, the activities of key photosynthesis enzymes PEPC, Rubisco, NADP-ME, NADP-MDH and PPDK of maize seedlings increased, which promoted the opening of stomata, improved the fixation efficiency of CO2, improved the photosynthetic process of maize plants and promoted plant growth. The promoting effect was the best when the concentration of MWCNTs was 800 mg·L-1 and the concentration of nano-SiO2 was 1500 mg·L-1. MWCNTs and nano-SiO2 can increase the activities of the enzymes GS, GOGAT, GAD and GDH related to nitrogen metabolism in maize leaves and roots, and can increase the content of pyruvate, so as to promote the synthesis of carbohydrates and the utilization of nitrogen and promote plant growth.

The effect of heavy atoms replacement sites on the luminescent ways of D-A-D type diphenyl sulfone molecules: Thermally activated delayed fluorescence and phosphorescence.

To obtain efficient pure organic thermally activated delayed fluorescence (TADF) materials, introducing non-metal heavy atoms is the common molecular design strategy, enhancing the intrinsically weak spin-orbit coupling (SOC) between singlet and triplet excited states by heavy-atom effect. However, the effect of heavy atom replacement sites is rarely explored. Herein, two series of molecules are investigated on the basis of different heavy atoms replacement sites to reveal the inherent structure-property relationships. The results show that DMSeC-DPS, which O is replaced with Se in periphery of donor units, could exhibit enhanced TADF performance. Because (i) sufficiently small singlet-triplet states energy gap (ΔEST) and enhanced SOC as well as mixed CT/LE character in T1 state could facilitate reverse intersystem crossing process, and (ii) non-radiative consumption are decreased for S1→S0 transition. Additionally, replacement of As at the connection site between donor and acceptor units folds evidently the geometry, leading to much larger ΔEST and enhanced exponentially SOC between T1 and S0 state due to the great participation of heavy atoms of the frontier molecules orbitals and heavy-atom effect. The pure LE character leads to relative stability and slight non-radiative consumption in T1 state. The luminescent way of DMOC-As-DPS would be transformed to phosphorescence. This work provides updated theoretical perspective for the effect of heavy atoms replacement sites and proposes a design strategy for the utilization of non-metal heavy atoms in efficiency organic lighting emitting diodes.