The FAcilitates Chromatin Transcription complex regulates the ratio of glycolysis to oxidative phosphorylation in neural stem cells.

Defects in the FAcilitates Chromatin Transcription (FACT) complex, a histone chaperone composed of SSRP1 and SUPT16H, are implicated in intellectual disability. Here, we reveal that the FACT complex promotes glycolysis and sustains the correct cell fate of neural stem cells/neuroblasts in the Drosophila 3rd instar larval central brain. We show that the FACT complex binds to the promoter region of the estrogen-related receptor (ERR) gene and positively regulates ERR expression. ERR is known to act as an aerobic glycolytic switch by upregulating the enzymes required for glycolysis. Dysfunction of the FACT complex leads to the downregulation of ERR transcription, resulting in a decreased ratio of glycolysis to oxidative phosphorylation (G/O) in neuroblasts. Consequently, neuroblasts exhibit smaller cell sizes, lower proliferation potential, and altered cell fates. Overexpression of ERR or suppression of mitochondrial oxidative phosphorylation in neuroblasts increases the relative G/O ratio and rescues defective phenotypes caused by dysfunction of the FACT complex. Thus, the G/O ratio, mediated by the FACT complex, plays a crucial role in neuroblast cell fate maintenance. Our study may shed light on the mechanism by which mutations in the FACT complex lead to intellectual disability in humans.

Machine-learning-assisted performance improvements for multi-resonance thermally activated delayed fluorescence molecules.

With favorable colour purity, multi-resonance thermally activated delayed fluorescence (MR-TADF) molecules exhibit enormous potential in high-definition displays. Due to the relatively small chemical space of MR-TADF molecules, it is challenging to improve molecular performance through domain-specific expertise alone. To address this problem, we focused on optimizing the classic molecule, DABNA-1, using machine learning (ML). Molecular morphing operations were initially employed to generate the adjacent chemical space of DABNA-1. Subsequently, a machine learning model was trained with a limited database and used to predict the properties throughout the generated chemical space. It was confirmed that the top 100 molecules suggested by machine learning present excellent electronic structures, characterized by small reorganization energy and singlet-triplet energy gaps. Our results indicate that the improvement in electronic structures can be elucidated through the view of the molecular orbital (MO). The results also reveal that the top 5 molecules present weaker vibronic peaks of the emission spectrum, demonstrating higher colour purity when compared to DABNA-1. Notably, the M2 molecule presents a high RISC rate, indicating its promising future as a high-efficiency MR-TADF molecule. Our machine-learning-assisted approach facilitates the rapid optimization of classical molecules, addressing a crucial requirement within the organic optoelectronic materials community.

H-Type-like Aggregation-Accelerated Singlet Fission Process in Dipyrrolonaphthyridinedione Thin Film: The Role of Charge Transfer/Excimer Mixed Intermediate State.

Through the combination of transient spectroscopy and theoretical simulations, an accelerated singlet fission (SF) process was evidently observed in the strongly coupled H-type-like aggregation thin films of a dipyrrolonaphthyridinedione skeleton. Results elucidate that in this H-type-like aggregation, the substantially stabilized charge transfer (CT) state is close in energy with singlet and excimer states, resulting in a CT/excimer mixed state, which could drive excited-state population escaping from excimer trap and promote an ultrafast and highly efficient SF process. Our results not only enrich the limited capacity of SF materials but also contribute to an in-depth understanding of SF dynamics in H-type aggregation, which is of fundamental importance for designing new SF sensitizers and implementing practical SF applications.

The study of intramolecular decay and intermolecular energy transfer for phosphorescent organic light-emitting devices.

Due to the huge potential of organic light-emitting diodes (OLEDs) in optical display devices, the exciton utilization of devices should be elucidated comprehensively to achieve a high external quantum efficiency (EQE). In this study, theoretical calculations of intramolecular excited state decay and intermolecular excitation energy transfer (EET) were conducted to investigate the differences in EQE between the two studied systems. Compared to the PtOO7-based system (using PtOO7 as the guest and 26mCPy as the host), the greater EQE of the PtON7-based system (using PtON7 as the guest and 26mCPy as the host) was mainly governed by the stronger energy transfer efficiency, with a secondary role being played by the higher photoluminescence quantum yield of the emitter. We confirmed that the different triplet EET (TEET) rates mainly contribute to the difference in the energy transfer efficiency between two studied systems, where the higher TEET rate from 26mCPy to PtON7 can be attributed to the restrained structural deformation of PtON7 and the desirable energy gap in the energy transfer process. Our calculations indicated that the electronic structure can evidently affect the intramolecular excited state decay and intermolecular excitation energy transfer. In addition, considering the environmental effects on the emission spectra of the emitters, the simulated spectra were consistent with the experimental measurements, which indicated that our descriptions of electronic structures are accurate; furthermore, an effective description of the molecular environment should be obtained. Our computational protocol successfully explored the relationship between the electronic structures, intramolecular excited state decay, and intermolecular excitation energy transfer, which can provide a deep understanding for the design and development of high-quality OLEDs from a molecular perspective.

Theoretical insights into the effect of ligands on platinum(ii) complexes with a bidentate bis(o-carborane) ligand structure.

Carboranes feature a wealth of unique structures and properties in phosphorescent transition-metal complexes (PTMCs). Herein, we identify the influence between the electronic structure in carboranes and the main ligand based on the density functional theory (DFT) and time-dependent density functional theory (TD-DFT), which affects the phosphorescence properties of carborane-containing Pt compounds. Furthermore, the mechanism, including singlet-triplet splitting energies ΔE(Sn - T1), transition dipole moment for S0 - Sn transitions, the zero-field splitting (ZFS), the radiative decay rate constant (kr), the Huang-Rhys factor (S), and the spin-orbit coupling (SOC) matrix elements have been carefully investigated. The results presented here reveal the functional action 1,1'-bis(o-carborane) contributes to the emission process owing to the manipulation of main ligand dtb-bpy and complex 1a shows promising prospects for achieving highly efficient phosphorescence via engineering the conjugation of the main ligand dtb-bpy.

What accounts for the color purity of tetradentate Pt complexes? A computational analysis.

In order to improve the texture of human visual perception and broaden the range of certain optical applications, many phosphorescent complexes exhibiting narrow emission spectra have been prepared through reasonable molecular design. For example, by adding a particular group such as tert-butyl (tbu) to a suitable position of PtON1 and PtON7, the peak width of a relevant vibronic band caused by the specific vibrational normal modes could be dramatically restrained in the emission spectra at room temperature. For the purpose of finding an effective approach to replace the trial-and-error manner, the microscopic mechanism of such high color purity was elucidated by computational investigation. In this study, we aim to identify the reason that causes sharp emission associated with the relevant vibrational normal modes. Here, these modes can be labeled to the emission peak by the vibrationally resolved emission spectra. Based on the displacement vectors of relevant normal modes and the vibrationally resolved spectra, the most possible reason for the higher color purity is that tbu in a specific location can restrain the structural deformation between the first triplet excited state (T1) and the ground state (S0). That is to say, the relevant Huang-Rhys factor (Sk) of specific vibrational modes would be decreased. For these compounds, the total bandwidth and the height of the intermediate and high-frequency regions which are in direct proportion to Sk would be decreased to obtain the higher color purity by tbu in a particular position. What is more, the best position for tbu in order to suppress the structural deformation was also considered. In the meantime, radiative (kr) and nonradiative (knr) decay rates of T1 were investigated to seek the effective phosphorescent complexes.