Cluster Core Research Articles

The SRG/eROSITA All-Sky Survey: Large-scale view of the Centaurus cluster

The Centaurus cluster is one of the brightest and closest clusters. Previous comprehensive studies were done only in its brightest part (r<30'), where the centers of the main substructures (Cen 30 and Cen 45) are located, and only a small fraction of the outskirts has been studied. Through this work, we aim to characterize the intracluster medium (ICM) morphology and properties of the Centaurus cluster out to the radius within which the density is 200 times the critical density of the Universe at the redshift of the cluster, R_ We utilized the combined five SRG/eROSITA All-Sky Survey data (eRASS:5) to perform X-ray imaging and spectral analyses in various directions out to large radii. We employed some image manipulation methods to enhance small- and large-scale features. Surface brightness profiles out to 2R_200 were constructed to quantify the features. We acquired the gas temperature, metallicity, and normalization per area profiles out to R_200. We compared our results with previous Centaurus studies, cluster outskirts measurements, and simulations. Comprehensive sky background analysis was done across the field of view in particular to assess the variation of the eROSITA Bubble emission that partially contaminates the field. The processed X-ray images show the known sloshing-induced structures in the core, such as the cool plume, cold fronts, and ram pressure-stripped gas. The spectra in the core (r≤11 kpc ) are better described with a two-temperature (2T) model than an isothermal model. With this 2T analysis, we measured a lower temperature from the cooler component (∼!1.0 keV ) and a higher metallicity (∼!1.6Z_⊙), signifying an iron bias. In the intermediate radial range, the temperature peaks at ∼!3.6 keV and we observed prominent surface brightness and normalization per area excesses in the eastern sector (Cen 45 location). Temperature enhancements near the location of Cen 45 imply that the gas is shock-heated due to the interaction with Cen 30. We reveal that the eastern excess emission extends even further out, reaching R_500. The peak excess of normalization is located at ∼!23' from the center ($8'$ behind the center of Cen 45) with a $45%$ and $7.7σ$ above the full azimuthal value. This might be the tail or ram pressure-stripped gas from Cen 45. There is a temperature decrease of a factor of about two to three from the peak to the outermost bin at -R_ . We find good agreement between the outer temperatures (r>R_2500) with the temperature profile from simulations and the temperature fit from cluster outskirts measurements. We detect significant surface brightness emission to the sky background level out to R_200 with a $3.5σ$, followed by $2.9σ$ at 1.1R_200. The metallicity at -R_ is low but within the ranges of other outskirts studies. We present the first whole azimuth beyond ∼!30' measurement of the ICM morphology and properties of the Centaurus cluster, and increasing the probed volume by a factor of almost 30. While the cluster core is rich in features as a result of active galactic nucleus feedback and sloshing, the cluster outskirts temperature of Centaurus follows the temperature profile of clusters in simulations as well as the temperature fit from other cluster outskirts measurements.

Identifying core symptom clusters based on symptom distress levels in patients with maintenance hemodialysis: a cross-sectional network analysis

Background To explore the symptom clusters of patients undergoing maintenance hemodialysis and construct a symptom network to identify the core symptoms and core symptom clusters, to provide reference for precise symptom management. Methods Conveniently selected 354 patients with maintenance hemodialysis were surveyed cross-sectionally using the general information questionnaire, the Dialysis Symptom Index and the Kidney Disease Questionnaire. Symptom clusters were extracted using exploratory factor analysis, and core symptom clusters were identified using hierarchical regression and network analysis. Results The most common and severe symptoms were fatigue, dry skin and itching, and the most distressing symptoms were fatigue, itching and trouble falling asleep. Within the symptom network, worry (r s = 1.0) had the highest strength, trouble staying asleep(r c = 0.01) had the highest closeness, and fatigue had the highest betweenness (r b = 30) and bridge strength (r bs = 0.53). A total of four symptom clusters were extracted, namely psychological symptom cluster, sleep disorder symptom cluster, uremia-related symptom cluster, and neurological symptom cluster. Hierarchical regression results showed that the psychological symptom cluster had the greatest impact on patients’ quality of life. Conclusions Fatigue was the most severe symptom and the bridge symptom, the uremia-related symptom cluster caused the greatest distress for patients, worry was the core symptom, and the psychological symptom cluster was identified as the core cluster. Clinical staff can provide effective symptom management and improve patient symptom burden by establishing intervention strategies centered on these results.

Sugarcane Pan-Transcriptome Identifying a Master Gene ScHCT Regulating Lignin and Sugar Traits.

Sugarcane has the most complex polyploid genome in the world, and sugar-related traits are one of the most important aims in sugarcane breeding. It is essential to construct a representative pan-transcriptome that contains all transcripts of a species for studies on genetic diversity, population expression, and omics analyses in sugarcane. In this study, we constructed the first comprehensive pan-transcriptome for sugarcane, and 8434 highly reliable open reading frames were found, which were not aligned with any published sugarcane genome. The core and dispensable gene clusters, as well as high- and low-expression gene clusters of the pan-transcriptome, were identified and analyzed. The integration of two sugar content differential transcriptome data revealed nine key candidate genes, including the ScHCT gene, encoding a crucial enzyme for lignin synthesis. Furthermore, the function of the ScHCT gene was validated inArabidopsis, which was negatively correlated with sugar content and positively correlated with lignin content. The interaction protein of ScHCT, ScABH, was screened via a yeast two-hybrid assay and further validated by point-to-point Y2H and bimolecular fluorescence complementation assays. The phenotype of the Arabidopsis abh mutant line revealed that loss of function of ABH resulted in a decrease of sucrose content in stem tissue. This study provides important reference information and genetic resources for sugarcane research and varietal improvement.

Dynamical evolution of massless particles in star clusters with NBODY6++GPU-MASSLESS

Context. Low-mass bodies, such as comets, asteroids, planetesimals, and free-floating planets, are continuously injected into the intra-cluster environment after expulsion from their host planetary systems. These objects can be modelled as massless particles (MLPs). Notably, the dynamics of large populations of MLPs have received little attention in the literature. Aims. We investigate the dynamical evolution of MLP populations in star clusters and characterise their kinematics and ejection rates. Methods. We present NBODY6++GPU-MASSLESS, a modified version of the N-body simulation code NBODY6++GPU that allows for fast integration of star clusters that contain large numbers of MLPs. NBODY6++GPU-MASSLESS contains routines specifically directed at the dynamical evolution of low-mass bodies, such as planets. Results. Unlike stars, MLPs do not participate in the mass segregation process. Instead, MLPs mostly follow the gravitational potential of the star cluster, which gradually decreases over time due to stellar ejections and stellar evolution. The dynamical evolution of MLPs is primarily affected by the evolution of the core of the star cluster. This is most apparent in the outer regions for clusters with higher initial densities. High escape rates of MLPs are observed before the core collapse, after which escape rates remain stable. Denser star clusters undergo a more intense core collapse, but this does not impact the dynamical evolution of MLPs. We find the speeds of escaping stars are similar to those of escaping MLPs when disregarding the high-velocity ejections of neutron stars during the first 50 Myr.

The Theory of Resonant Cosmic Ray–driven Instabilities—Growth and Saturation of Single Modes

Cosmic-ray (CR) feedback is critical for galaxy formation as CRs drive galactic winds, regularize star formation in galaxies, and escape from active galactic nuclei to heat the cooling cores of galaxy clusters. The feedback strength of CRs depends on their coupling to the background plasma and, as such, on the effective CR transport speed. Traditionally, this has been hypothesized to depend on the balance between the wave growth of CR-driven instabilities and their damping. Here, we study the physics of CR-driven instabilities from first principles, starting from a gyrotropic distribution of CR ions that stream along a background magnetic field. We develop a theory of the underlying processes that organize the particles’ orbits and in particular their gyrophases, which provides an intuitive physical picture of (i) wave growth as the CR gyrophases start to bunch up lopsidedly toward the local wave magnetic field, (ii) instability saturation as a result of CRs overtaking the wave and damping its amplitude without isotropizing CRs in the wave frame, and (iii) CR backreaction onto the unstable plasma waves as the CR gyrophases follow a pendulum motion around the wave magnetic field. Using our new fluid-particle-in-cell code fluid-SHARP, we validate our theory on the evolution and excitation of individual unstable modes, such as forward- and backward-propagating Alfvén and whistler waves. We show that these kinetic simulations support our theoretical considerations, thus potentially foreshadowing a revision of the theory of CR transport in galaxies and galaxy clusters.

Features of the development and functioning of tourist clusters

The article presents comparative characteristics of tourism and industrial clusters in current business conditions based on the following criteria: cluster core, marketing and promotion, quality standards and production technology, cluster subjects, cluster performance.

A [Zn4O(fcCO2)6] oxocarboxylate cluster: synthesis, chemical and physical properties

Abstract The reaction of the ferrocene derivative Fe(ƞ 5-C5H4CO2H)(ƞ 5-C5H4CH=CH2) (=fcCO2H) (1) with the zinc reagents [Zn(OAc)2]·xH2O (OAc = acetate; 2a, x = 0; 2b, x = 2) or ZnEt2 (3) in non-aqueous solvents toluene or tetrahydrofuran resulted in the formation of the cluster [Zn4O(fcCO2)6] (4). The structure of 4 in the solid state has been determined by single-crystal X-ray diffraction analysis. Cluster 4 crystallizes in the triclinic space group P 1 ‾ $\overline{1}$ . In 4, the cluster core is set-up by four zinc(II) ions which are forming the vertices of a tetrahedron with a μ 4-oxygen atom in its center. Six μ-fcCO2 units bridge the edges of the tetrahedron. IR spectroscopy confirms with ∆ν CO2 = 91 cm−1 (∆ν CO2 = ν CO2,asym − ν CO2,sym) the μ-bridging character of the fcCO2 entities. Cyclic voltammetry studies showed a reversible redox event at E°′ = 245 mV versus FcH/FcH+ (FcH = Fe(ƞ 5-C5H5)2) for 4 with the six fcCO2 redox events superimposed. High-resolution ESI-TOF measurements verified the identity of 4.

First evidencing of guest‐induced spin transition for dinuclear Fe(III) complex supported by calix[4]arene Schiff base ligand

For the first time the partial low spin (LS) ‐ high spin (HS) state transition back, caused by trapped guest molecule release from the macrocyclic cavity of calix[4]arene ligand, decorated with salicylideneamine coordinating binding sites, was evidenced for new dinuclear [FeIII2] diamond core cluster, displaying mixed cis‐/trans‐N2O4 coordination environment for metal centers. Such unique spin state transition behavior, triggered by the changing of calix[4]arene backbone conformation, giving rise to a new paradigm of fine‐tuning spin‐dependent functionality in materials design, was unambiguously established by the 57Fe Mössbauer spectroscopy in combination with the single crystal X‐ray diffraction, IR, TGA‐DSC analysis.

Research on NBA Event Prediction Based on Hybrid Machine Learning Model

NBA is one of the top basketball events in the world. It is of great significance to predict NBA events comprehensively and accurately. Therefore, this paper puts forward the research on the prediction of NBA events based on a hybrid machine learning model. Construct a hybrid machine learning model, set the pre-processing flow of NBA event prediction data, solve the probability core cluster of NBA event prediction data, and form a data stream mining matrix of NBA event prediction; based on the integrated learning method in machine learning, according to the principle of constructing the prediction index of NBA events, the prediction index is constructed; based on the deep learning method in machine learning, the weight of target factors is used as a parameter to measure the prediction accuracy, and hierarchical evaluation is carried out to realize the prediction of NBA events. The experimental results show that the research method shows a high goodness of fit in all NBA games, and the predicted results are highly consistent with the actual results, and the predicted results are closer to the real results, with small root mean square error and average absolute error, which has a good prediction effect.

Reverse Osmosis Membrane Engineering: Multidirectional Analysis Using Bibliometric, Machine Learning, Data, and Text Mining Approaches.

Membrane engineering is a complex field involving the development of the most suitable membrane process for specific purposes and dealing with the design and operation of membrane technologies. This study analyzed 1424 articles on reverse osmosis (RO) membrane engineering from the Scopus database to provide guidance for future studies. The results show that since the first article was published in 1964, the domain has gained popularity, especially since 2009. Thin-film composite (TFC) polymeric material has been the primary focus of RO membrane experts, with 550 articles published on this topic. The use of nanomaterials and polymers in membrane engineering is also high, with 821 articles. Common problems such as fouling, biofouling, and scaling have been the center of work dedication, with 324 articles published on these issues. Wang J. is the leader in the number of published articles (73), while Gao C. is the leader in other metrics. Journal of Membrane Science is the most preferred source for the publication of RO membrane engineering and related technologies. Author social networks analysis shows that there are five core clusters, and the dominant cluster have 4 researchers. The analysis of sentiment, subjectivity, and emotion indicates that abstracts are positively perceived, objectively written, and emotionally neutral.

Nonlinear Optical Response of Tetrel-Modified Tetraphenyl-Adamantane Clusters.

The second harmonic generation (SHG) properties of adamantane-based tetraphenyl clusters are predicted from first principles and analyzed on the basis of the involved electronic transitions. In particular, the effect of a tetrel substitution in the cluster core on the nonlinear optical response is investigated. Electronic transitions spatially localized at the substituents are found to be responsible for the optical nonlinearities. The intensity of the SHG signal grows with the atomic number of the considered tetrel. As the substitution does not distort the cluster core or substantially alter its symmetry, the enhanced SHG intensity is traced to a higher electron density at the substituents. The latter results in a larger spatial overlap of the states involved in the electronic transitions, which increases their probability. The presented results provide a theoretical foundation for the design of tailored nonlinear optical sources.

Water Encapsulated [(Fe4Se4)Se4]6- Clusters in [Na6(H2O)18][Fe4Se8

[Na6(H2O)18][Fe4Se8] was synthesized using hydrothermal methods and characterized by single-crystal X-ray diffraction, 57Fe Mössbauer spectroscopy, magnetization, and muon spin resonance (μSR) measurements. The cubic crystal structure (space group I23, a = 11.785 Å, Z = 2) contains heterocubane-type clusters with Td symmetry. Four additional selenium atoms complete the tetrahedral coordination around the iron atoms, forming units. Notably, the selenide ligands do not interact with the sodium cations, as the Fe4Se86- cluster in [Na6(H2O)18][Fe4Se8] is exclusively surrounded by water molecules via weak Se···H-O hydrogen bonds. This is particularly remarkable given that [Fe4Q4] clusters are typically unstable in water. Quantum chemical calculations (DFT) confirm the crystal structure and improve the positions of the hydrogen atoms. 57Fe Mössbauer spectroscopy reveals that the spin ordering of the mixed-valence [Fe42.5+Se4]2+ cluster core mirrors the antiparallel spin arrangement found in analogous iron-sulfur clusters, such as , in protein-bound systems. An increase of the quadrupole splitting at low temperatures indicates changes of the orbital occupations. μSR Experiments show a reduction of the spin fluctuation frequency until the system becomes static at low temperatures, but no evidence of a S = 0 state above 2 K.

Measuring the intracluster medium velocity structure within the A3266 galaxy cluster

We present a detailed analysis of the velocity structure of the hot intracluster medium (ICM) within the A3266 galaxy cluster, including new observations taken between June and November 2023. Firstly, morphological structures within the galaxy cluster were examined using a Gaussian gradient magnitude (GGM) and an adaptively smoothed GGM filter applied to the EPIC-pn X-ray image. Then, we applied a novel XMM-Newton EPIC-pn energy scale calibration, which uses instrumental Cu Kα as a reference for the line emission, to measure the line-of-sight velocities of hot gas within the system. This approach enabled us to create two-dimensional projected maps for velocity, temperature, and metallicity, showing that the hot gas displays a redshifted systemic velocity relative to the cluster redshift across all fields of view. Further analysis of the velocity distribution through non-overlapping circular regions demonstrates consistent redshifted velocities extending up to 1125 kpc from the cluster core. Additionally, the velocity distribution was assessed along regions following surface brightness discontinuities, where we observed redshifted velocities in all regions, with the largest velocities reaching 768 ± 284 km/s. Moreover, we computed the velocity probability density function (PDF) from the velocity map. We applied a normality test, finding that the PDF adheres to an unimodal normal distribution consistent with theoretical predictions. Lastly, we computed a velocity structure function for this system using the measured line-of-sight velocities. These insights advance our understanding of the dynamic processes within the A3266 galaxy cluster and contribute to our broader knowledge of ICM behavior in merging galaxy clusters.

Expansion kinematics of young clusters

Context. Most stars form in clusters or associations, but only a small number of these groups are expected to remain bound for longer than a few megayears. Once star formation has ended and the molecular gas around young stellar objects has been expelled via feedback processes, most initially bound young clusters lose the majority of their binding mass and begin to disperse into the Galactic field. Aims. This process can be investigated by analysing the structure and kinematic trends in nearby young clusters, particularly by analyzing the trend of expansion, which is a tell-tale sign that a cluster is no longer gravitationally bound and dispersing into the field. Methods. We combined Gaia DR3 five-parameter astrometry with calibrated RVs for members of the nearby young cluster λ Ori (Collinder 69). Results. We characterised the plane-of-sky substructure of the cluster using the Q-parameter and the angular dispersion parameter. We find evidence that the cluster contains a significant substructure but that this is preferentially located away from the central cluster core, which is smooth and likely remains bound. We found strong evidence for expansion in λ Ori in the plane of sky by using a number of metrics, but we also found that the trends are asymmetric at the 5σ significance level, with the maximum rate of expansion being directed nearly parallel to the Galactic plane. We subsequently inverted the maximum rate of expansion of 0.144−0.003+0.003 kms−1 pc−1 to give an expansion timescale of 6.944−0.142+0.148 Myr, which is slightly larger than the typical literature age estimates for the cluster. We also found asymmetry in the velocity dispersion as well as signatures of cluster rotation, and we calculated the kinematic ages for individual cluster members by tracing their motion back in time to their closest approach to the cluster centre.

Four luminous cyclen-protected Silver-Alkynyl clusters

For investigating the coordination ability and the reactivity of Cyclen, four luminous cyclen-protected Silver-Alkynyl clusters, named [Ag5(CCtBu)2(Cyclen)3(OTf)·(OTf)2] (1), [Ag4(CCPh)(Cyclen)3(H2O)·(OTf)3] (2), [Ag4(CCPh)(Cyclen)3(H2O)·(BF4)3·(CH3OH)2] (3), and [Ag12(CCPh)6(Cyclen)6(BF4)2·(BF4)4] (4), where OTf = Trifluoromethanesulfonate, have been prepared by adding Cyclen into the different silver-alkynyl systems. Their composition and charge state, have been confirmed by X-ray single-crystal structural analysis, Electrospray Ionization Mass Spectrometry (ESI-MS), and other methods. The thermogravimetric analysis (TGA) reveals the decomposition temperature of all four clusters was over 150 °C, showing excellent thermal stability. Contrastively studies of their emission properties by the photoluminescence (PL) spectra indicate the variation of the cluster cores have a great impact on their emission color in the solid state at 77 K. This study introduces a new way to prepare new structures of silver-alkynyl clusters, and will enlighten further explorations of the structure control of silver clusters with excellent emission.

Activation of Strong π-Acids at [Fe4S4]+ Clusters Enabled by a Noncanonical Electronic Structure.

Although Fe-S clusters are privileged metallocofactors for the reduction of N2, CO, and other π-acidic substrates, their constituent metal ions─high-spin Fe2+ and Fe3+─are typically not amenable to binding and activating strong π-acids. Here, we demonstrate that [Fe4S4]+ clusters can overcome this limitation by adopting a noncanonical electronic structure. Specifically, we report the synthesis and characterization of a series of 3:1 site-differentiated [Fe4S4]+ clusters in which the unique Fe site is bound by one of 10 electronically variable arylisocyanide ligands. Rather than being continuously tuned as a function of the arylisocyanides' electronic properties (e.g., as quantified by linear free energy relationships), the structures of the clusters are divided into two groups: (i) those with moderately π-acidic isocyanides, which adopt a "typical" structure characterized by standard bond metrics and geometric distortions from tetrahedral symmetry, and (ii) those with more strongly π-acidic isocyanides, which adopt a "contracted" structure with an unusually symmetric geometry and a compressed cluster core. Computational studies revealed that although the "typical" structure has a canonical electronic structure, the "contracted" structure has a noncanonical arrangement of spin density, with a full complement of π-backbonding electrons and more substantial Fe-Fe delocalization. These features of the "contracted" structure enable substantial C≡N bond weakening of the strongest π-acceptors in the series. More generally, the experimental characterization of the "contracted" electronic isomer suggests that other noncanonical electronic structures of Fe-S clusters remain to be discovered.

SAR Study on Thiolato-Bridged Triosmium Carbonyl Clusters: Higher Reactivity Does Not Equal Higher Antiproliferative Activity.

A structure-activity relationship study on triosmium clusters of the general formula Os3(μ-H)(μ-SC6H4X)(CO)10 (2-X, where X = o-, m- or p-NH2; o-, m- or p- OH; p-H, -Br, -NO2, -COOH or -CH2COOH) show that their antiproliferative activity is through the cluster core, and the nature and position of the phenyl ring substituent X shows a significant impact on the activity. Clusters with an electron-withdrawing group are more reactive but are thus quickly consumed through reaction with serum, while those with an electron-donating group persists sufficiently to enter the cells and result in higher antiproliferative activity. Interestingly, m-substituted clusters and those with lipophilicity >6.0 also exhibit higher antiproliferative activity. In contrast, o-substituted clusters capable of intramolecular hydrogen bonding have lower cytotoxicity. The cluster 2-m-OH, with higher antiproliferative activity and lower reactivity with serum, is a potential lead compound for further mode of action studies.

Effect of Ni-Doping on the Optical, Structural, and Electrochemical Properties of Ag29Nanoclusters.

Atomically precise metal nanoclusters (NCs) can be compositionally controlled at the single-atom level, but understanding structure-property correlations is required for tailoring specific optical properties. Here, the impact of Ni atom doping on the optical, structural, and electrochemical properties of atomically precise 1,3-benzene dithiol (BDT) protected Ag29 NCs is studied. The Ni-doped Ag29 (NiAg28(BDT)12) NCs, are synthesized using a co-reduction method and characterized using electrospray ionization mass spectrometry (ESI MS), ion mobility spectrometry (IMS), and X-ray photoelectron spectroscopy (XPS). Only a single Ni atom doping can be achieved despite changing the precursor concentration. Ni doping in Ag29 NCs exhibits enhanced thermal stability, and electrocatalytic oxygen evolution reaction (OER) compared to the parent NCs. Density functional theory (DFT) calculations predict the geometry and optical properties of the parent and NiAg28(BDT)12 NCs. DFT is also used to study the systematic single-atom doping effect of metals such as Au, Cu, and Pt into Ag29 NCs and suggests that with Ni and Pt, the d atomic orbitals contribute to creating superatomic orbitals, which is not seen with other dopants or the parent cluster. The emission mechanism is dominated by a charge transfer from the ligands into the Ag core cluster regardless of the dopant.

First Evidence of Au‐CH3 Bonding in Superatomic Au13 Clusters

AbstractChemical reduction of a dinuclear [(di‐NHC)Au2Cl2(di‐NHC)] complex (NHC=imidazol‐2‐ylidene), using excess NaBH4 as reducing agent in presence of dichloromethane (DCM) as solvent, provides a molecular cluster with formula [Au13(di‐NHC)5(CH3)2]Cl3, exhibiting covalent bonds between gold atoms of the cluster core and methyl groups. The presence of Au‐CH3 bonds, which is unprecedented in gold cluster chemistry, is confirmed by high resolution mass spectrometry (HRMS), NMR and the reactivity of the reported cluster in solid state. The cluster has been further characterized with single crystal X‐ray diffractometry, UV‐Vis and emission spectroscopies. The cluster displays remarkable stability in solution, which is indicative of the possible role played by Au‐CH3 bond formation in the conventional preparation of molecular gold nanoclusters by reduction with excess borohydride in DCM.

Mixed Carboxylate Ligands Bridging Tetra-Pr3+-Encapsulated Antimonotungstate: Syntheses, Structure, and Catalytic Activity for Imidazoles Synthesis.

Multinuclear Pr-containing antimonotungstate [Pr4(H2O)10W6O13(mal)2(OAc)(B-α-SbW9O33)4]21- (Pr-1, mal = malate anion, OAc = acetate anion), bridged by organic carboxylic acid, was synthesized through a one-pot assembly reaction and structurally characterized. Pr-1 is composed of four [B-α-SbW9O33]9- fragments fused together by an organic-inorganic hybrid central [Pr4(H2O)10W6O13(mal)2(OAc)]15+ cluster core through 24 μ2-O atoms. Notably, the central cluster comprises unprecedented decanuclear Pr4(H2O)10W6O13 jointly decorated by two types of carboxylic acid ligands. This integration of rare earth-containing antimonotungstate with mixed organic carboxylate ligands is very rare in POMs chemistry. Pr-1 exhibits excellent catalytic activity in the cyclo-condensation reaction involving benzil, aldehyde, and NH4OAc. A series of 2,4,5-trisubstituted imidazoles were synthesized in remarkable yields using iPrOH as a green solvent.