Nykhrikova, Ekaterina Vasilyevna

Tatarin S.V., Krasnov L., Nykhrikova E.V., Minin M.M., Smirnov D.E., Churakov A.V., Bezzubov S.

Cyclometalated iridium(III) complexes are excellent emitters for organic light-emitting diodes (OLEDs), but the design of these compounds requires substantial cost and experimental efforts. In this work, we aimed at a...

Nykhrikova E.V., Kiseleva M.A., Kalle P., Mariasina S.S., Kozyukhin S.A., Tatarin S.V., Bezzubov S.I.

Tatarin S., Krasnov L., Nykhrikova E., Minin M., Smirnov D., Churakov A., Bezzubov S.

Cyclometalated iridium(III) complexes are excellent emitters for phosphorescent organic light-emitting diodes, but the design of such complexes require substantial cost and experimental efforts. In turn, the predictive power of density functional theory calculations is seldom enough for reliable prediction of the excited state properties of iridium(III) complexes. In this work, we aimed at data-driven prediction of the emission energies and photoluminescence quantum yields of such complexes. To this end, we created a database (IrLumDB) that contains experimentally measured luminescence properties for over 1200 literature bis-cyclometalated iridium(III) complexes. Based on this database, we developed machine learning models that are capable of predicting the energy of emission maxima and photoluminescence quantum yields for the iridium phosphors with mean absolute errors of 18.26 nm and 0.129, respectively, requiring only SMILES of ligands. Furthermore, we validated the model for emission wavelength prediction on the set of 33 experimentally obtained luminescence spectra for newly synthesized and characterized iridium(III) complexes. Our data-driven methodology will complement quantum chemical calculations as an efficient alternative approach for the prediction of the excited-state properties of large sets of bis-cyclometalated iridium(III) complexes, facilitating computational discovery of efficient emitters. The emission properties prediction and the dataset exploration are available at https://irlumdb.streamlit.app/.

Zakharov A.Y., Kovalenko I.V., Meshcheriakova E.A., Nykhrikova E.V., Zharova A.O., Kiseleva M.A., Kalle P., Tekshina E.V., Kozyukhin S.A., Emets V.V., Bezzubov S.I.

Zhdanov G., Nyhrikova E., Meshcheryakova N., Kristavchuk O., Akhmetova A., Andreev E., Rudakova E., Gambaryan A., Yaminsky I., Aralov A., Kukushkin V., Zavyalova E.

Biosensors combining the ultrahigh sensitivity of surface-enhanced Raman scattering (SERS) and the specificity of nucleic acid aptamers have recently drawn attention in the detection of respiratory viruses. The most sensitive SERS-based aptasensors allow determining as low as 104 virus particles per mL that is 100-fold lower than any antibody-based lateral flow tests but 10–100-times higher than a routine polymerase chain reaction with reversed transcription (RT-PCR). Sensitivity of RT-PCR has not been achieved in SERS-based aptasensors despite the usage of sophisticated SERS-active substrates. Here, we proposed a novel design of a SERS-based aptasensor with the limit of detection of just 103 particles per ml of the influenza A virus that approaches closely to RT-PCR sensitivity. The sensor utilizes silver nanoparticles with the simplest preparation instead of sophisticated SERS-active surfaces. The analytical signal is provided by a unique Raman-active dye that competes with the virus for the binding to the G-quadruplex core of the aptamer. The aptasensor functions even with aliquots of the biological fluids due to separation of the off-target molecules by pre-filtration through a polymeric membrane. The aptasensor detects influenza viruses in the range of 1·103–5·1010 virus particles per ml.

Chang Q., Zhang K., Yan C., Xie L., Yi Y., Su W., Liu W.

Organic light-emitting diodes (OLEDs) based on phosphorescent materials are among the most promising technologies for displays and lightings. For red-emitting heteroleptic iridium complexes (HICs), vast and major research has been focused on the design and synthesis of cyclometalated ligands, while relatively little attention has been given to ancillary ligands which also play important roles in manipulating the optoelectronic and electroluminescent properties of HICs. Seven deep red-emitting HICs were designed and synthesized by systematically modifying the alkyl groups in β-diketone-type ancillary ligands. These HICs exhibited similar physical and optoelectronic properties, with OLED devices based on these materials achieving consistent emission peaks at 624 nm and CIE coordinates of (0.68, 0.32). Among the synthesized HICs, Ir(dmippiq)₂(dmeacac), featuring 3,7-dimethyl-4,6-nonanedione as the ancillary ligand, demonstrated the best OLED performance, achieving a champion external quantum efficiency (EQE) of 18.26%. This result highlights that engineering the alkyl groups in β-diketone ancillary ligands can significantly enhance device performance.

Andreev E., Zakaryan H., Harutyunyan T., Molokanova L., Pinaeva U., Rossouw A., Nechaev A., Apel P., Aroutiounian R.

Cao B., Lin P., Wang Y., Yang W., Ren L., Ge Z., Sui H., Gao Y., Liu M., Bei G., Zhou S., Zhou Q., Cui F.

The global spread of viral respiratory infections continues to pose a substantial threat to human health, exacerbating the societal burden. Timely and precise detection of viruses is pivotal in mitigating pandemic transmission. Currently, the prevalent diagnostic techniques for viruses include real-time quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), and colloidal gold assays. However, intricate workflows and protracted processing times of RT-qPCR and ELISA preclude real-time diagnostics, despite their high accuracy. Colloidal gold assays offer rapid turnaround. However, their accuracy and sensitivity are limited, particularly in the context of emerging variants like SARS-CoV-2, which renders them suboptimal test tools. Mounting evidence suggests that surface-enhanced Raman spectroscopy (SERS), with its streamlined operation, rapid analysis, high specificity and sensitivity, holds significant potential as a superior alternative test tool. This review consolidates various SERS-based approaches for detecting respiratory infection virus (RIV) and delineates their characteristics. The unique strengths of SERS technology, including its exceptional sensitivity, robust specificity, and expedited turnaround times, earmark it as particularly well-suited for large-scale instant screening of viral infections within populations.

Cialla-May D., Bonifacio A., Bocklitz T., Markin A., Markina N., Fornasaro S., Dwivedi A., Dib T., Farnesi E., Liu C., Ghosh A., Popp J.

Surface enhanced Raman spectroscopy (SERS) is meeting the requirements in biomedical science being a highly sensitive and specific analytical tool.

Liu J., Lai H., Li G.

Since the outbreak of COVID-19 pandemic, there is a rising demand of sensitive and fast detection of biomarkers. Surface-enhanced Raman spectroscopy (SERS) is a non-destructive and fast detection technology that highly meets the requirement of biomarkers detection either in speediness or sensitivity. However, direct SERS analysis of biomarkers from multifarious samples is hard due to the serious matrix interference, low content, fluorescence background interference, and weak affinity. With the help of proper sample preparation integrated analytical strategies, target biomarkers in complex samples can be separated, purified, and enriched for SERS analysis. Currently, SERS detection of biomarkers is experiencing a rapid development. Thus, a review is presented to better understand the research progress in the field. Firstly, the analytical strategies enable SERS for biomarkers detection are summarized, which provide the possibility of rapid, selective, and sensitive detection, including magnetic separation, chromatography separation, membrane separation, phase extraction, derivatization SERS-activation, and highly integrated microfluidics. Then, the analytical strategies applied for biological SERS application are listed according to different biomarkers, including breath volatile organic compounds, microbial pathogens, biotoxin, extracellular vesicles, etc. Finally, the progresses of biomarkers detection by SERS are concluded, and perspectives on current challenges and shortcomings limited the further application are presented.

Li J., Guan R., Wuethrich A., Yan M., Cheng J., Liu G., Zhan J., Trau M., Sun Y.

Sharma S., Kumar R.P., Yadav R.M.

As an effective and ultrasensitive molecule detection technique, Surface-enhanced Raman spectroscopy (SERS) exigencies efficient and highly responsive substrates to further enhance its sensitivity and utility. In this work, preparation and...

Zhdanov G., Gambaryan A., Akhmetova A., Yaminsky I., Kukushkin V., Zavyalova E.

Surface-enhanced Raman spectroscopy (SERS)-based aptasensors for virus determination have attracted a lot of interest recently. This approach provides both specificity due to an aptamer component and a low limit of detection due to signal enhancement by a SERS substrate. The most successful SERS-based aptasensors have a limit of detection (LoD) of 10–100 viral particles per mL (VP/mL) that is advantageous compared to polymerase chain reactions. These characteristics of the sensors require the use of complex substrates. Previously, we described silver nanoisland SERS-substrate with a reproducible and uniform surface, demonstrating high potency for industrial production and a suboptimal LoD of 4 × 105 VP/mL of influenza A virus. Here we describe a study of the sensor morphology, revealing an unexpected mechanism of signal enhancement through the distortion of the nanoisland layer. A novel modification of the aptasensor was proposed with chromium-enhanced adhesion of silver nanoparticles to the surface as well as elimination of the buffer-dependent distortion-triggering steps. As a result, the LoD of the Influenza A virus was decreased to 190 VP/mL, placing the nanoisland SERS-based aptasensors in the rank of the most powerful sensors for viral detection.

Ахметова А.И., Яминский И.В., Советников Т.О.

Атомно-силовая микроскопия – это уникальный инструмент для изучения 3D-морфологии биологических объектов и измерения их свойств. Для применения метода и интерпретации полученных данных немаловажную роль играет программное обеспечение, которое позволяет корректно обработать изображения, убрать артефакты сканирования и собрать воедино ценную информацию об объектах [1, 2]. В ПО "ФемтоСкан Онлайн" реализовано несколько функций, которые существенно облегчают обработку изображений и сбор данных об интересующих объектах.

Veneranda M.

Lavrova M.A., Verzun S.A., Mishurinskiy S.A., Sirotin M.A., Bykova S.K., Gontcharenko V.E., Mariasina S.S., Korshunov V.M., Taydakov I.V., Belousov Y.A., Dolzhenko V.D.

A series of cyclometalated complexes of ruthenium (II) with four different substituents in the aryl fragment of benzimidazole was synthesized in order to study the effect of substituent donation on the electronic structure of the substances. The resulting complexes were studied using X-ray diffraction, NMR spectroscopy, MALDI mass spectrometry, electron absorption spectroscopy, luminescence spectroscopy, and cyclic voltammetry as well as DFT/TDDFT was also used to interpret the results. All the complexes have intense absorption in the range of up to 700 nm, the triplet nature of the excited state was confirmed by measurement of luminescence decay. With an increase in substituent donation, a red shift of the absorption and emission bands occurs, and the lifetime of the excited state and the redox potential of the complex decrease. The combination of these properties shows that the complexes are excellent dyes and can be used as photosensitizers.

Макаревич Ю.Е., Огаркова Н.К., Сосунов Е.А., Сулимова О.В., Скабицкий И.В., Попова А.С., Панина М.В., Нестеренко М.Ю., Варгафтик М.Н., Якушев И.А.

Makarevich J.E., Ogarkova N.K., Sosunov E.A., Sulimova O.V., Skabitsky I.V., Popova A.S., Panina M.V., Nesterenko M.Y., Vargaftik M.N., Yakushev I.A.

New bimetallic pivalate Pd(II) complex [PdNi(OOCtBu)4(HOOCtBu)] (I) has been synthesized from [PdNi(OOCMe)4] and used as a starting reagent in a further complexation reaction. Cyclometallated binuclear carboxylate palladium complexes [(OOCMe)Pd(2‑phpy)]2 (II) and [(OOCtBu)Pd(2‑phpy)]2 (III) have been obtained by the reaction between heterometallic compounds [Pd(OOCR)4Ni] (R = Me, tBu) and 2-phenylpyridine (2-phpy). The reaction proceeds at room temperature under mild conditions. All the compounds obtained have been isolated in crystalline form from a medium of nonpolar solvents, characterized by single-crystal X-ray diffraction analysis, and deposited at the Cambridge Crystallographic Data Center (CCDC nos. 2256606 for I, 2247942 for II, and 2247943 for III).

Sharma S., Kumar R., Yadav R.M.

Surface-enhanced Raman spectroscopy (SERS) sensing effective substrates made of polymer and nitrogen-doped graphene quantum dots (N-GQDs) have attracted significant interest. SERS substrates are intensively used to detect pollutants/hazardous materials in various forms. In this study, we have integrated N-GQDs into polyacrylonitrile (PAN) polymer and fabricated the SERS active substrates, which facilitate the detection of methylene blue (MB). Scanning electron microscopic characterization demonstrated three-dimensional (3D) porous structural/morphology of the composite films. The porous structure formation might be due to solvent evaporation during film fabrication. The goal was to develop biocompatible and low-cost SERS substrates for MB detection. Synthesized 3D porous PAN/N-GQDs nanocomposite structure was shown to have an enhancement factor (EF) of 104 that of the polymer surface due to the multiple hotspot resonance effect, excitation dependent emission property and charge transfer induced in the structure. This phenomenon indicates that PAN/N-GQDs nanocomposite films have high potential as sensitive and selective nanosensors for the detection of MB. Current research results may lead to new and superior SERS substrates with increased sensitivity and selectivity.

Kukushkin V., Ambartsumyan O., Subekin A., Astrakhantseva A., Gushchin V., Nikonova A., Dorofeeva A., Zverev V., Keshek A., Meshcheryakova N., Zaborova O., Gambaryan A., Zavyalova E.

Rapid and reliable techniques for virus identification are required in light of recurring epidemics and pandemics throughout the world. Several techniques have been distributed for testing the flow of patients. Polymerase chain reaction with reverse transcription is a reliable and sensitive, though not rapid, tool. The antibody-based strip is a rapid, though not reliable, and sensitive tool. A set of alternative tools is being developed to meet all the needs of the customer. Surface-enhanced Raman spectroscopy (SERS) provides the possibility of single molecule detection taking several minutes. Here, a multiplex lithographic SERS aptasensor was developed aiming at the detection of several respiratory viruses in one pot within 17 min. The four labeled aptamers were anchored onto the metal surface of four SERS zones; the caught viruses affect the SERS signals of the labels, providing changes in the analytical signals. The sensor was able to decode mixes of SARS-CoV-2 (severe acute respiratory syndrome coronavirus two), influenza A virus, respiratory syncytial virus, and adenovirus within a single experiment through a one-stage recognition process.

Chang Q., Zhang K., Yan C., Xie L., Yi Y., Su W., Liu W.

Organic light-emitting diodes (OLEDs) based on phosphorescent materials are among the most promising technologies for displays and lightings. For red-emitting heteroleptic iridium complexes (HICs), vast and major research has been focused on the design and synthesis of cyclometalated ligands, while relatively little attention has been given to ancillary ligands which also play important roles in manipulating the optoelectronic and electroluminescent properties of HICs. Seven deep red-emitting HICs were designed and synthesized by systematically modifying the alkyl groups in β-diketone-type ancillary ligands. These HICs exhibited similar physical and optoelectronic properties, with OLED devices based on these materials achieving consistent emission peaks at 624 nm and CIE coordinates of (0.68, 0.32). Among the synthesized HICs, Ir(dmippiq)₂(dmeacac), featuring 3,7-dimethyl-4,6-nonanedione as the ancillary ligand, demonstrated the best OLED performance, achieving a champion external quantum efficiency (EQE) of 18.26%. This result highlights that engineering the alkyl groups in β-diketone ancillary ligands can significantly enhance device performance.

Wang S., Yam C.Y., Hu L., Hung F., Chen S., Che C., Chen G.

The multi-level Δ-learning method significantly advances kr prediction by bridging TDDFT results with experimental values. This approach improves prediction reliability, making it essential for accurate material evaluation.

Choroba K., Palion-Gazda J., Penkala M., Rawicka P., Machura B.

The impact of cyclometalating ligands on the photophysical behaviour of heteroleptic Ir(iii) complexes with imidazo[4,5-f][1,10]phenanthroline. [Ir(ppy)2(imphen)]+ is a 3MLLCT emitter, while [Ir(pybzth)2(imphen)]+ has a predominant 3LCN∩C character.

Tatarin S.V., Bezzubov S.I.

Li S., Zhang Y., Dai Y., Xu J., Meng Q., Wen X., Qiao J.

AbstractThe development of highly efficient pure near‐infrared (NIR) emitting organic materials with emission beyond 800 nm is extremely challenging due to the limitation of the energy gap law. Herein, three efficient NIR emitting iridium(III) complexes are developed adopting pyrido[3,4‐b]pyrazine derivatives as the cyclometalated C^N ligands, namely (Epptt)2Iracac (1), (pptt)2Iracac (2), and (ppCz)2Irtmd (3). Due to the enhanced donor–acceptor interaction inside the ligand, the conjugation‐extended and electron‐richer N‐phenylcarbazole unit at the C‐part of the ligands endows complex 3 with a large bathochromic shift of emission peak from 796 to 862 nm in toluene solution, compared with thieno[3,2‐b]thiophene C‐part in complex 2. The solution‐processed OLEDs based on complex 3 achieved a record high maximum external quantum efficiency of 3.75% and low efficiency roll‐off with the emission peak at 830 nm, a champion efficiency in the Ir(III) based OLEDs with emission peak exceeding 800 nm. This work opens a new avenue for the development of high‐efficiency pure NIR organic emitters based on Ir(III) complexes for various applications.

Krasnov L., Tatarin S., Smirnov D., Bezzubov S.

AbstractIridium(III) complexes nowadays became rising stars in various health-related applications. Thus, there is a necessity to assess cytotoxicity of the synthesized molecules against cancer/normal cell lines. In this report, we present a dataset of 2694 experimental cytotoxicity values of 803 iridium complexes against 127 different cell lines. We specify the experimental conditions and provide representation of the complexes molecules in machine-readable format. The dataset provides a starting point for exploration of new iridium-based cellular probes and opens new possibilities for predictions of toxicities and data-driven generation of new organometallic anticancer agents.

Lv A., Li G., Zhang P., Tao R., Li X., Ren X., Li P., Liu X., Yuan X., Liu Z.

Considerable attention has been devoted to the exploration of organometallic iridium(III) (IrIII) complexes for their potential as metallic anticancer drugs. In this study, twelve half-sandwich IrIII imidazole-phenanthroline/phenanthrene complexes were prepared and characterized. Complexes exhibited promising in-vitro anti-proliferative activity, and some are obviously superior to cisplatin towards A549 cells. These complexes possessed suitable fluorescence, and a non-energy-dependent uptake pathway was identified, subsequently leading to their accumulation in the lysosome and the lysosomal damage. Additionally, complexes could inhibit the cell cycle (G1-phase) and catalyze intracellular NADH oxidation, thus substantiating the elevation of intracellular reactive oxygen species (ROS) level, which confirming the oxidative mechanism. Western blotting further confirmed that complexes could induce A549 cell apoptosis through the lysosomal-mitochondrial anticancer pathway, which was inconsistent with cisplatin. In summary, these complexes offer fresh concepts for the development of organometallic non‑platinum anticancer drugs.

Gao S., Cao C., Liu Z., Yao Z.

Pal Y., Fiala T.A., Swords W.B., Yoon T.P., Schmidt J.

AbstractWe report a deep learning‐based approach to accurately predict the emission spectra of phosphorescent heteroleptic [Ir( )2( )]+ complexes, enabling the rapid discovery of novel Ir(III) chromophores for diverse applications including organic light‐emitting diodes and solar fuel cells. The deep learning models utilize graph neural networks and other chemical features in architectures that reflect the inherent structure of the heteroleptic complexes, composed of and ligands, and are thus geared towards efficient training over the dataset. By leveraging experimental emission data, our models reliably predict the full emission spectra of these complexes across various emission profiles, surpassing the accuracy of conventional DFT and correlated wavefunction methods, while simultaneously achieving robustness to the presence of imperfect (noisy, low‐quality) training spectra. We showcase the potential applications for these and related models for in silico prediction of complexes with tailored emission properties, as well as in “design of experiment” contexts to reduce the synthetic burden of high‐throughput screening. In the latter case, we demonstrate that the models allow us to exploit a limited amount of experimental data to explore a wide range of chemical space, thus leveraging a modest synthetic effort.

Alkhaibari I.S., Zhang X., Zhao J., Stonelake T.M., Knighton R.C., Horton P.N., Coles S.J., Buurma N.J., Richards E., Pope S.J.

Blanco L., Uroz A., Gutiérrez K., Cabrera S., Collado A., Alemán J.

Yan Z., Wang Z., Zhuang X., Li Z., Kai C., Song X., Liang J., Bi H., Wang Y.

AbstractThe development of phosphorescent materials with ultrapure emission is of great significance for wide‐color‐gamut organic light‐emitting diodes (OLEDs). Herein, a ligand steric interlocking strategy is introduced to achieve the narrowband emission of phosphorescent Ir(III) complexes. The steric interlocking effect contributed by the short distance between ligands leads to enhanced rigidity, and suppresses the high‐frequency vibrations of oICz‐Ir. In this context, oICz‐Ir exhibits an ultrapure green phosphorescence with a small full width at half maximum (FWHM) of 23 nm peaking at 521 nm in solution. Furthermore, the oICz‐Ir‐based OLED achieves a maximum external quantum efficiency (EQEmax) of 18.9%, an excellent color purity with Commission Internationale de L'Eclairage coordinate y (CIEy) of 0.69, making it the purest green bottom‐emitting phosphorescent OLEDs. Meanwhile, with oICz‐Ir as the sensitizer, a phosphorescence sensitized fluorescent OLED shows an excellent EQEmax of 31.1% with the CIEy of 0.7.

Yan Z., Mao M., Liu Q., Yuan L., Luo X., Liao X., Cai W., Zheng Y.

AbstractAttaining phosphorescent materials with narrowband emission is crucial for advancing wide‐color‐gamut organic light‐emitting diode (OLED). Herein, a rigid modification strategy is introduced for iridium(III) complexes to achieve the narrowband red emission with negligible 0–1 peak. By introducing the rigid indolo[3,2,1‐jk]carbazole (ICz) into the cyclometalated ligand, Ir(III) complexes, ICziq‐Ir and ICzqz‐Ir, exhibit pure red phosphorescence with emission peaks at 608 and 613 nm and full widths at half‐maximum (FWHMs) of 37 and 38 nm (0.12 and 0.13 eV) in toluene, respectively. Furthermore, the specific site modification of ICzqz‐Ir greatly suppresses the high‐frequency vibration of the structure, resulting in the narrowband photoluminescent spectrum close to the Gaussian distribution with superior color purity. The OLEDs utilizing ICziq‐Ir and ICzqz‐Ir demonstrate maximum external quantum efficiencies of 21.4 and 17.8% as well as mild efficiency roll‐off. Remarkably, the electroluminescence spectra exhibit similar narrowband red emission with FWHMs of 37 and 43 nm and CIE coordinates of (0.65, 0.35) and (0.66, 0.34), attesting to the excellent color purity of the phosphorescent OLEDs.

Wu C., Shi K., Li S., Yan J., Feng Z., Tong K., Zhang S., Zhang Y., Zhang D., Liao L., Chi Y., Wei G., Kang F.

This review explores the latest advancements iridium(III) phosphorescent blue emitters by focusing on the design strategies employed for saturated blue phosphorescent OLEDs with enhanced operational lifetime. Saturated blue emission remains a challenging aspect of OLED technology, and iridium(III) complexes have emerged as promising materials to address this issue. The molecular design principles, ligand engineering and host materials that facilitate the achievement of highly efficient blue phosphorescent emission are explored. Additionally, various host-guest systems and device architectures that have been employed to prolong the operational lifetime of these OLEDs are systemtatically examined. The review highlights recent breakthroughs and prospects, including the synthesis of novel iridium(III) complexes, advanced device engineering strategies, and potential application in next-generation displays and lighting technologies. Therefore, this comprehensive analysis serves as a valuable resource for researchers and industry professionals engaged in the development of advanced OLEDs with improved efficiency and longevity.

Carson M.C., Liu C.R., Kozlowski M.C.