Strong Charge Research Articles

Vinylene‐Linked Donor‐π‐Acceptor Metal‐Covalent Organic Framework for Enhanced Photocatalytic CO2 Reduction

AbstractIntramolecular charge separation driving force and linkage chemistry between building blocks are critical factors for enhancing the photocatalytic performance of metal‐covalent organic framework (MCOF) based photocatalyst. However, robust achieving both simultaneously has yet to be challenging despite ongoing efforts. Here we develop a fully π‐conjugated vinylene‐linked multivariate donor‐π‐acceptor MCOF (D‐π‐A, termed UJN‐1) by integrating benzyl cyanides linker with multiple functional building blocks of electron‐rich triphenylamine and electron‐deficient copper‐cyclic trinuclear units (Cu‐CTUs) moieties, featuring with strong intramolecular charge separation driving force, extended conjugation degree of skeleton, and abundant active sites. The incorporation of Cu‐CTUs acceptor with electron‐withdrawing ability and concomitantly giant charge separation driving force can efficiently accelerate the photogenerated electrons transfer from triphenylamine to Cu‐CTUs, revealing by experiments and theoretical calculations. Benefiting from the synergistically effect of D‐π‐A configuration and vinylene linkage, the highly‐efficient charge spatial separation is achieved. Consequently, UJN‐1 exhibits an excellent CO formation rate of 114.8 μmol g−1 in 4 h without any co‐catalysts or sacrificial reagents under visible light, outperforming those analogous MCOFs with imine‐linked (UJN‐2, 28.9 μmol g−1) and vinylene‐linked COF without Cu‐CTU active sites (UJN‐3, 50.0 μmol g−1), emphasizing the role of charge separation driving force and linkage chemistry in designing novel COFs‐based photocatalyst.

Highly and Deep Red-Luminescent Bisphenylamine-Appended Benzocarcogendiazole Fluorophores.

Benzocarcogendiazole units have been frequently utilized for optoelectronics such as organic solar cells because of their robustness, rigidity, and band-gap tunability based on their strong electron-withdrawing properties. Focusing on the luminescent characteristics, these molecules have been utilized to demonstrate highly sensitive chromisms because of the potential of charge transfer. Here, we demonstrate deep red-emissions in bis(4-tert-butylphenyl)amine-appended benzocarcogendiazole-based donor-acceptor-donor (D-A-D) fluorophores, namely 1 and 2. Because benzocarcogendiazole and bis(4-tert-butylphenyl)amine serve as strong electron acceptor and donor, respectively, strong intramolecular charge transfer (ICT) enables long wavelength of photoluminescence (PL) even in the small molecular weight. Although photoluminescence (PL) in long wavelength tends to exhibit quite low absolute PL quantum efficiency (ΦPL), the values of solutions 1 and 2 are quite high (up to 50 %). According to X-ray crystallographic characterizations and DFT calculations, these high ΦPL values are attributable to the segregated π-planes of benzocarcogendiazole units, which is induced by the bulky substituents of bis(4-tert-butylphenyl)amines.

Modulating Charge-Transfer Excited States of Multiple Resonance Emitters via Intramolecular Covalent Bond Locking.

Advanced multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters with high efficiency and color purity have emerged as a research focus in the development of ultra-high-definition displays. Herein, we disclose an approach to modulate the charge-transfer excited states of MR emitters via intramolecular covalent bond locking. This strategy can promote the evolution of strong intramolecular charge-transfer (ICT) states into weak ICT states, ultimately narrowing the full-width at half-maximum (FWHM) of emitters. To modulate the ICT intensity, two octagonal rings are introduced to yield molecule m-DCzDAz-BNCz. Compounds m-CzDAz-BNCz and m-DCzDAz-BNCz exhibit bright light-green and green fluorescence in toluene, with emission maxima of 504 and 513 nm, and FWHMs of 28 and 34 nm, respectively. Sensitized organic light-emitting diodes (OLEDs) employing emitters m-CzDAz-BNCz and m-DCzDAz-BNCz exhibit green emission with peaks of 508 and 520 nm, Commission Internationale de L'Eclairage (CIE) coordinates of (0.12, 0.65) and (0.19, 0.69), and maximum external quantum efficiencies (EQEs) of 30.2 % and 32.6 %, respectively.

Boosted four-top production at the LHC: A window to Randall-Sundrum or extended color symmetry

Scenarios seeking to address the issue of electroweak symmetry breaking often have heavy colored gauge bosons coupling preferentially to the top quark. Considering the bulk Randall-Sundrum as a typical example, we consider the prospects of the first Kaluza-Klein mode (G(1)) of the gluon being produced at the LHC in association with a tt¯ pair. The enhanced coupling not only dictates that the dominant decay mode would be to a tt¯ pair, but also to a very large G(1) width, necessitating the use of a renormalized G(1) propagator. This, along with the presence of large backgrounds (specially tt¯jj), renders a conventional cut-based analysis ineffective, yielding only marginal significances of only around 2σ. The use of machine learning (ML) techniques alleviates this problem to a great extent. In particular, the use of artificial neural networks helps us identify the most discriminating observables, thereby allowing a significance in excess of 4σ for G(1) masses of ∼4 TeV. Published by the American Physical Society 2024

An Azaryl-Ketone-Based Thermally Activated Delayed Fluorophore with Aggregation-Induced Emission for Efficient Organic Light-Emitting Diodes with Slow Efficiency Roll-Offs.

Achieving the concurrent manifestation of thermally activated delayed fluorescence (TADF) and aggregation-induced emission (AIE) within a single molecular system is highly sought after for organic light-emitting diodes (OLEDs), yet remains rare. In this study, we present a novel TADF-AIE dye, named PQMO-PXZ, which has been designed, synthesized, and systematically characterized. Our comprehensive investigation, which includes structural analysis, theoretical calculations, and optical studies, evaluates the potential of PQMO-PXZ for integration into OLEDs. Unlike existing azaryl-ketone-based emitters, PQMO-PXZ exhibits red-shifted emission and enhanced luminescence efficiency, due to its rigid structure and strong intramolecular charge transfer characteristics. Significantly, PQMO-PXZ demonstrates pronounced AIE properties and TADF with a short delayed lifetime. When utilized as the emissive core, OLED devices based on PQMO-PXZ achieve a respectable external quantum efficiency of up to 11.8 % with minimal efficiency roll-off, underscoring PQMO-PXZ's promise as a highly efficient candidate for OLED applications.

An interpretation of scalars in SO(32)

We propose an interpretation for the adjoint representation of the SO(32) group to classify the scalars of a generic Supersymmetric Standard Model having just three generations of particles, via a flavour group SU(5). We show that this same interpretation arises from a simple postulate of self-consistence of composites for these scalars. The model looks only for colour and electric charge, and it pays the cost of an additional chiral +4/3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$+4/3$$\\end{document} quark per generation.

Preparation and characterization of ovomucin self-assembly nanoparticles under glycerol compression for astaxanthin delivery: Sustained release and antioxidant activity.

Astaxanthin (AST) is a natural hydrophobic nutrient with various biological activities, but its low solubility limits its application. In this study, self-assembly nanoparticles were prepared by ovomucin (OVM) and Ca2+ with the enhancement of glycerol to deliver AST. Glycerol compressed the particle size of nanoparticles from 175.7±1.8 to 142.9±0.6nm, and the nanoparticles had a strong negative charge (-28.9±0.6mV). Ultraviolet-visible spectroscopy and X-ray diffraction (XRD) confirmed the successful encapsulation of AST in an amorphous form with a high encapsulation efficiency (82.9%±2.1%). Fourier transform infrared and circular dichroism analyses demonstrated that nanoparticles formation mainly involved electrostatic interactions and hydrophobic interactions. AST in nanoparticles presented excellent gastric juice resistance and sustained release ability, whereas free radical scavenging efficiency reached up to 75%. In addition, the nanoparticles had no apparent toxicity to cell viability. This study is expected to provide a new insight into the safe and efficient delivery of AST, while demonstrating the potential of OVM as a delivery carrier in the food and health industries.

Tuning local charge polarization of covalent organic frameworks for enhanced photocatalytic uranium (VI) reduction

The introduction of local charge polarization is an effective strategy to improve the electrostatic potential difference of covalent organic frameworks (COFs) photocatalysts. Herein, BPDA-COF with donor–acceptor (D-A) structure was firstly synthesized by using triphenyl-triazine and biphenyl monomers. Subsequently, the hydroxyl and bis(2-methoxyethyl)ether (PEO)-chains with increasing local charge polarization were introduced to synthesize DHBD-COF and PEO-COF, respectively. PEO-COF with electronegative and flexible PEO-chains created a strong local charge polarization to enhance the electrostatic potential differences, thus promoting the spontaneous transfer of electrons and inhibiting the recombination of electrons and holes. Furthermore, the super-hydrophilic PEO-chains provided super-strong uranium mass transfer capacity. Benefiting from these, PEO-COF exhibited excellent photocatalytic uranium reduction capabilities (1427.9 mg g−1). This work provides a novel insight to adjust the local charge polarization at the molecular level and broadens the strategy of photocatalytic reduction of U(VI) with COFs.

Probing the nature of the anticharmed-strange pentaquark states: Mass spectra, decays, and magnetic moments

Within the framework of the quark delocalization color screening model, a systematic investigation of the anticharmed-strange pentaquark system is performed using the resonance group method. The currently estimations predict three bound states with estimated masses to be 2886 MeV, 3039 MeV, and 3153 MeV, respectively. Additionally, three resonance states are identified in various scattering phase shifts processes. Among them, two resonance states ΣD¯ and Σ*D¯* with quantum number 12(12−) are detected in channels ND¯s* and ND¯, and ΣD¯* and ΛD¯, with masses and decay widths of (MR=3053–3055 MeV, Ttotal=13.0–13.4 MeV) and (MR=3389–3390 MeV, Ttotal=10.4 MeV), respectively. In the ΛD¯* and ΣD¯* channels, a resonance state with quantum number 12(32−) is discovered, with its mass and decay width being 3250–3252 MeV and 4.4,MeV, respectively. These predicted pentaquark states have c¯snnn quark compositions, allowing them to be recognized as genuine pentaquark states. To validate these predictions, it is expected that upcoming experiments will further explore the predicted resonance and bound states in these possible decay channels. Published by the American Physical Society 2024

Dual-emission spiropyran-functionalized covalent organic framework–based nanofiber mat microsensors for fluorescence colorimetric sensing of trace water

A dual-emission spiropyran-functionalized covalent organic framework (MCH@COF) was synthesized using acyl chlorination for the first time in this study. The excited state of MCH@COF had a strong intramolecular charge transfer property, and its solvent-solvent interaction with polar solvents caused MCH@COF to exhibit solvatochromic behavior. Furthermore, the face-to-face stacking of the H-aggregating form of MCH@COF was found to be disrupted in the presence of water. Consequently, MCH@COF demonstrated exceptional sensitivity (detection limit = 0.02 %, v/v) and a wide linear range (0 %–50 %, v/v) as a ratiometric fluorescence probe for water. To expand its applications, MCH@COF was doped with a nanofiber mat comprising polylactic acid/polyvinylpyrrolidone, resulting in the development of a microsensor. By combining the microsensing device with a heating volatilization extraction method, the visual fluorescence colorimetric detection of water in solid samples was realized. The method showed the advantages of small-sample requirement (20 mg), low matrix interference (achieved through the separation of matrix and water via heating volatilization), high sensitivity (maximum color difference (ΔC) of 166.14), and suitability for rapid field detection (sensing time of 4 min, with color change observed using the naked eye under visible light).

Symmetrically Fluorinated D-π-A Structured Cyanine Dye for Highly Efficient NIR-II Imaging-Guided Cancer Phototheranostics.

Near-infrared-II (NIR-II) fluorescence imaging-guided photothermal therapy (PTT) represents a cutting-edge approach for precise tumor diagnosis and treatment, providing real-time therapeutic efficacy evaluation. However, a significant challenge lies in the creation of phototheranostic agents that provide robust imaging and efficient photothermal conversion. To address this, a donor-π-acceptor (D-π-A) structure heptamethine cyanine derivative, IR1116, that confers a strong intramolecular charge transfer effect is developed. To enhance its applicability, IR1116 is formulated with DSPE-PEG to create a water-dispersible NIR-II phototheranostic nanoheater, NPIR1116. This nanoheater benefits from the incorporation of an electron-withdrawing group, leading to reduced photooxidation activity and significantly improved photostability. NPIR1116 exhibits strong NIR-II absorption and fluorescence, peaking at 1004 and 1116nm, respectively, as well as a photothermal conversion efficiency of 79% under 1064nm lasers. In vitro and in vivo studies showed the efficacy of NPIR1116 in tumor imaging via NIR-II fluorescence and its ability to effectively induce tumor cell apoptosis under 1064nm laser irradiation. These findings underscore the potential of NPIR1116 in NIR-II fluorescence imaging-guided PTT for tumor treatment, paving the way for further advancements in NIR-II dye development and bioimaging technologies.

Bicontinuous nickel/tin oxide films with enhanced photoelectrochemical hydrogen production efficiency

Self-assembled bicontinuous NiO:SnO2 films are proposed for enhanced photoelectrochemical hydrogen production efficiency due to their high interface-to-volume ratio and three-dimensional interconnectivity. The X-ray diffraction confirms the superior crystallinity of the bicontinuous NiO:SnO2 films. Bicontinuous NiO:SnO2 films reveal a heterostructure of mixed NiO and SnO2 phases, where the NiO phase exhibits the distribution of small grains, whereas the SnO2 phase exhibits large agglomerates of SnO2 crystals embedded in the NiO structure. The bicontinuous NiO:SnO2 films exhibit lower bandgap energy and higher electrical conductivity compared to pure NiO and pure SnO2 films. The photoresponsivity of the bicontinuous oxide films is higher than pure NiO and pure SnO2 films. These results imply the presence of strong charge interactions at the three-dimensional interfaces in bicontinuous NiO:SnO2 films. The hydrogen revolution reaction analysis confirms that the bicontinuous NiO:SnO2 films exhibit higher photoelectrocatalyst hydrogen production activity compared to pure NiO and pure SnO2 films.

Tip-like copper sites on high curvature supports for non-covalent to covalent interaction tuning in CO2 photoreduction

Single-atom engineering offers a promising method to transform CO2 into high-value chemicals. The local coordination structure design of the metal-support is crucial for overcoming slow reaction kinetics. In this study, Cu single atoms are immobilized on curved Bi12O17Br2 surface to create a tip-like metal site structure named Cutip-Bi12O17Br2. Due to the high curvature Bi12O17Br2 surface with tensile strain, the tip Cu creates significant electronegativity differences between adjacent Bi atomic sites, creating the vigorous polarization centers. The strong charge redistribution character of tip asymmetric Cu-Bi site favor the polarization of CO bond in nonpolar CO2 and adjust the noncovalent to covalent interaction of reaction intermediates. Benefiting from these features, the optimized Cutip-Bi12O17Br2 enhance the CO production rate by a factor of 34 relative to bulk-Bi12O17Br2, reaching a rate of 96.99 μmol g−1 h−1. This work provides a comprehensive understanding of the structural regulation of single-atom on high curvature surface for CO2 photoreduction.

Design and synthesis of heterocycle-based push-pull NLOphores: A comprehensive study of their linear and non-linear optical properties

Push-pull chromophores, with strong intramolecular charge transfer (ICT), exhibit high ground-state polarization, driving strong NLO responses. The donor and acceptor abilities of the groups in the investigated compounds influence ICT, so the nonlinear response of these compounds was analyzed in relation to their strength. Two different families of NLOphores were synthesized through [2 + 2] cycloaddition-retroelectrocyclizations of heterocycle-based electron-rich alkynes with tetracyanoethylene (TCNE) and tetracyanoquinodimethane (TCNQ). The λmax values of push-pull chromophores, particularly for charge transfer bands, fall within the range of 424–758 nm. The linear and nonlinear optical properties of these NLOphores were subsequently examined through a combination of experimental and theoretical methods. NLO measurements were conducted using a validated custom-made Z-scan device. The nonlinear absorption coefficients range from −1.44 × 10−4 cm.W−1 to −9.90 × 10−4 cm.W−1, while nonlinear refractive indices range from −1.59 × 10−7 cm2. W−1 to −2.26 × 10−6 cm2. W−1. As expected from their molecular structures, the TCNQ products displayed stronger nonlinear responses than the TCNE products.

An S-Scheme CeO2/Bi2O2S heterojunction photoanode for the photoelectrocatalytic degradation of sulfamethoxazole in synthetic and real wastewater

We prepared an S- scheme heterojunction photoanode using cerium oxide (CeO2) and bismuth oxysulfide (Bi2O2S) for the photoelectrocatalytic degradation of sulfamethoxazole. The CeO2 /Bi2O2S photoanode was synthesised via an in-situ hydrothermal method, ensuring strong contact and efficient charge transfer between the CeO2 and Bi2O2S. The materials and photoanode were characterized with XRD, XPS, photoluminescence, and photoelectrochemistry. The S-scheme configuration observed in the formation of heterojunction in CeO2 /Bi2O2S photoanode was responsible for the improved photoelectrocatalytic performance for the visible light-assisted degradation of sulfamethoxazole. Operational parameters such as the effect of pH and current density were examined. The extent of sulfamethoxazole mineralisation was calculated to be 72 % using the total organic carbon (TOC) measurement. The LC-MS analysis was used to predict the degradation pathway and products. Furthermore, the photoelectrocatalytic efficiency of the CeO2/Bi2O2S photoanode was investigated in real wastewater matrices with TOC removal of 54 %. Therefore, the S scheme CeO2/Bi2O2S photoanodes lends itself to photoelectrochemical water treatment applications.

Size polydisperse model ionic liquid under confinement: A molecular dynamics study

The performance of an electric double-layer capacitor is strongly influenced by the choice of electrolyte, and the use of ionic liquid (IL) mixtures as an electrolyte has shown great promise. In this study, a model IL made of a mixture of anions and size-polydisperse cations in equal numbers and confined between two electrodes is investigated by means of molecular dynamics simulations. In particular, using the extent of size-polydispersity (characterized by polydispersity index, δ) as a control parameter, we systematically explore its effect on the local structure, charge profile, ion size distribution in the vicinity of electrode surfaces, and differential capacitance. It is observed that the charge density profiles near cathode, i.e., region comprising both Stern and diffused layers, are significantly affected under the variation of δ in addition to the electrode charge density. Ion population, ordering of different-size cations, and its effective size in the vicinity of electrodes under neutral and applied potential conditions are also quantified. An interesting observation is that the effective cation size in the Stern layer decreases with increasing value of δ in the case of moderate to strong electrode surface charge density. This behaviour can be qualitatively understood from the interplay of enthalpic and entropic forces in the system. Finally, a non-monotomic dependence of capacitance on δ is observed with maximum value of capacitance at a rather small value of δ(≈3%) for the model system.

Achieving Controllable Thermochromic Fluorescence via Synergistic Intramolecular Charge Transfer and Molecular Packing

Thermochromic fluorescent materials (TFMs) have attracted significant attention due to their unique fluorescent colorimetric response to temperature. However, existing TFMs still suffer from weak stimulus responsiveness, broad temperature response ranges, uncontrollable emission color changes, and low quantum yields. In this study, we address these issues by designing and synthesizing three diketone‐boron complexes with distinct emission wavelengths (NWPU‐(2‐4)). Utilizing a molecular engineering strategy to manipulate intramolecular charge transfer transitions and molecular packing modes, our synthesized complexes exhibit efficient fluorescence emission in both solution and solid states. Moreover, their emission wavelengths are highly sensitive to environmental polarity. By incorporating these compounds into thermosensitive matrices of long‐chain alkanes, we produced TFMs with varied fluorescence emission peak variation ranges. Notably, the TFM based on NWPU‐4, owing to its strong charge transfer transitions and dense J‐aggregate packing configuration, not only exhibits intense fluorescence emission spanning the deep red to near‐infrared spectrum but also displays a remarkable 90 nm broad range of thermochromic properties. Ultimately, it was successfully applied to programmable, thermally controlled, multi‐level information encryption.

Achieving Controllable Thermochromic Fluorescence via Synergistic Intramolecular Charge Transfer and Molecular Packing.

Thermochromic fluorescent materials (TFMs) have attracted significant attention due to their unique fluorescent colorimetric response to temperature. However, existing TFMs still suffer from weak stimulus responsiveness, broad temperature response ranges, uncontrollable emission color changes, and low quantum yields. In this study, we address these issues by designing and synthesizing three diketone-boron complexes with distinct emission wavelengths (NWPU-(2-4)). Utilizing a molecular engineering strategy to manipulate intramolecular charge transfer transitions and molecular packing modes, our synthesized complexes exhibit efficient fluorescence emission in both solution and solid states. Moreover, their emission wavelengths are highly sensitive to environmental polarity. By incorporating these compounds into thermosensitive matrices of long-chain alkanes, we produced TFMs with varied fluorescence emission peak variation ranges. Notably, the TFM based on NWPU-4, owing to its strong charge transfer transitions and dense J-aggregate packing configuration, not only exhibits intense fluorescence emission spanning the deep red to near-infrared spectrum but also displays a remarkable 90 nm broad range of thermochromic properties. Ultimately, it was successfully applied to programmable, thermally controlled, multi-level information encryption.

Laser-synthesized TiN-based nanoparticles as novel efficient electrostatic nanosorbent for environmental water cleaning

Abstract Dyes used in industries such as textile, paper, and leather are known to be harmful to both human health and aquatic ecosystems, which makes critically important the search of effective and sustainable methods for their removal from wastewater in order to mitigate the detrimental pollution effects. Here, we show that titanium nitride nanoparticles (TiN NPs) synthesized by scalable methods of pulsed laser ablation in liquid ambient (water, acetone and acetonitrile) can serve as extremely efficient sorbents for water decontamination from dye molecules (methylene blue, crystal violet, and malachite green). Our tests show that adsorption of TiN NPs is associated with the electrostatic effect due to a strong negative charge of laser-synthesized TiN NPs and the presence of pores in the NPs. Comprehensive characterization using scanning and transmission electron microscopy, along with Raman spectroscopy, evidenced that the appearance of surface charge is related to the formation of under-stoichiometric TiN (TiN1-x), associated with the predominance of nitrogen vacancies. This study identifies an optimal configuration of vacancy defects that maximizes dye adsorption, with TiN NPs synthesized in water exhibiting superior performance, achieving a dye sorption capacity of 136.5 mg/g at room temperature for methylene blue, which corresponds to best earlier reported values for nanomaterials. This study not only extends the utility of TiN NPs to environmental remediation but also highlights the critical influence of synthesis conditions on their functional properties, offering a pathway towards the design of more effective materials for pollution control.

Emission in the Biological Window from AIE-Based Carbazole-Substituted Furan-Based Compounds for Organic Light-Emitting Diodes and Random Lasers.

The emission quenching observed in devices utilizing luminescent materials such as solid thin films is a prevalent issue. Consequently, searching for new organic luminescent compounds exhibiting aggregation-induced emission (AIE) behavior and characterized by relatively simple and cost-effective synthesis is of crucial interest among applications from optoelectronics and organic lasing branches. Herein, we report the optical properties of three furan-based carbazole-substituted compounds, namely, tBuCBzSO2Ph, tBuCBzSPh, and tBuCbzTCF, exhibiting the aforementioned AIE phenomenon. The optical properties of dyes were determined in classical spectroscopic experiments supported by quantum-chemical calculations. The thermal investigations and electrochemical properties of dyes were performed to verify their usefulness in the construction of organic light-emitting diodes (OLEDs). In pursuit of this objective, OLEDs with a different design were fabricated, and their performance was subject to evaluation. In more detail, the different design strategies relying on the utilization of neat-dye films, as well as the preparation of dye-doped poly(9-vinylcarbazole):2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (PVK:PBD) matrices were examined. The analysis that was conducted indicated the superior potential of tBuCBzSPh for optoelectronic applications. Notably, the positive impact of the AIE effect on the emission of the OLEDs and the ability to establish the lasing phenomenon in asymmetric, poly(methyl methacrylate) (PMMA)-doped polymeric slab waveguides were verified. The study showed that the combination of the strong intramolecular charge transfer (ICT) effect with dye aggregation enables the tuning of the emission of the OLED toward the first biological window, making examined dyes promising candidates for biomedical purposes. The same optical region can be attained for laser emission at relatively low pumping conditions, reaching as low as 7.3 kW of optical power for the tBuCBzSO2Ph compound.