Selenide Clusters Research Articles

Controlled Synthesis and Phase Transition Mechanisms of Palladium Selenide: A First-Principles Study.

Using density functional theory, we carefully calculated the relative stability of monolayer, few-layer, and cluster structures with Penta PdSe2, T-phase PdSe2, and Pd2Se3-phase. We found that the stability of Penta PdSe2 increases with the number of layers. The Penta PdSe2, T-phase PdSe2, and Pd2Se3 monolayers are all semiconducting, with band gaps of 1.77, 0.81, and 0.65 eV, respectively. The formation energy of palladium selenide clusters with different phase structures is calculated, considering the cluster size, stoichiometry, and chemical environment. Under typical experimental conditions, Pd2Se3 phase clusters are found to be dominant, having the lowest formation energy among all of the phases considered, with this dominance increasing as cluster size grows. Adjusting the Pd-Se ratio in the environment allows for controlled synthesis of specific palladium selenide phases, providing theoretical insights into the nucleation mechanisms of PdSe2 and other transition metal chalcogenides.

Evolutionary Pathways of T-Phase Transition Metal Dichalcogenides: A Comprehensive Study of PtxSey Clusters.

Understanding the transition from nonplanar to planar clusters is crucial for the controllable synthesis of transition metal dichalcogenide (TMDC) monolayers. Using PtSe2 as a model, we investigate how the chemical environment influences the nucleation and growth stages of monolayer PtSe2 through structure searching and first-principles calculations. We established a comprehensive database of platinum selenide clusters (PtxSey, x = 1-10), analyzing 2095 unique clusters and identifying 191 stable isomers and 63 structures with the lowest formation energy on the convex hull. Our findings reveal a chemical environment-dependent phase transition from 3D structures to the planar T-phase of PtxSey clusters, representing an evolutionary route for PtSe2 growth. Clusters such as PtSe6, Pt2Se9, Pt3Se10, and Pt7Se10 in Pt-rich environments, as well as Pt2Se15 and Pt10Se32 in Se-rich environments, have been found to exhibit high stability. Additionally, the impact of varying chemical potentials of Pt and Se on the stability of these clusters is explored. PtSe4 and PtSe6 are found to be highly stable under most experimentally achievable chemical potential conditions and may serve as dominant precursors during PtSe2 growth. This work advances our understanding of the nucleation processes of PtSe2 and other T-phase TMDC materials.

Adsorption of cadmium selenide clusters: A novel approach to enhance solar energy conversion using armchair graphene nanoribbons

Tailoring the electronic, optical, and transport properties of low-dimensional semiconductor materials is essential to improve the light-conversion efficiency of thin-film solar cell materials. Here, using first-principles calculations and non-equilibrium Green functions, we investigate the enhancement of optoelectronic and transport properties of armchair graphene nanoribbons (AGNRs) upon adsorption of cadmium selenide clusters. Upon adsorption of a CdSe diatomic molecule on an AGNR, the most energetically favorable configuration is the cadmium end sitting on top of a carbon atom. The corresponding electronic bandgap reduces ∼5 times with respect to that of the pristine system, thanks to the formation of a polaron state formed by the p-orbital of the selenide atom. Upon adsorption of CdSe cyclohexane molecules, the bandgap of this system slightly shrinks by 0.121 eV with respect to the pristine system. The charge accumulation induced by these clusters significantly enhances the absorption coefficient of the adsorbed systems, resulting in a red shift of the optical spectra toward the infrared region. More interestingly, by solving the Bethe–Salpeter equations with the Tamm–Dancoff approximation, we provide a direct link between the first-principles optical prediction and experimental observations. In addition, the electron transfer from these molecules to the hosted systems increases the transmission spectra in the vicinity of the Fermi level, leading to a remarkable electronic current passing through these scattering regions. These results highlight the role of cadmium selenide clusters in enhancing the light-to-energy conversion efficiency of next-generation solar cell devices.

Coordination of apical O- and S-donor ligands to the hexarhenium(III) cluster core: Investigating the electrochemistry of alcoholate containing cluster complexes

The alkoxide containing rhenium selenide cluster, [Re6Se8(PEt3)5(OMe)]+, was synthesized from [Re6Se8(PEt3)5(py)]2+ and NaOMe. This methoxide complex was then used as a precursor in the preparation of two other site-differentiated species, the phenoxy [Re6Se8(PEt3)5(OPh)]+ and thiophenolate [Re6Se8(PEt3)5(SPh)]+ cluster complexes. The synthesis of the 4-methylbenzenethiolate complex, [Re6Se8(PEt3)5(STol)]+, prepared via a different synthetic route, is also reported along with the single crystal X-ray diffraction analyses of the methoxy, phenoxy and thiophenolate complexes. The electrochemistry of the alcoholate complexes reveals a multitude of redox processes; solutions of these complexes were also found to emit in the red-NIR region.

Tailoring supertetrahedral cadmium/tin selenide clusters into a robust framework for efficient elimination of Cs+, Co2+, and Ni2+ ions

The elimination of radionuclides Cs+, Co2+, and Ni2+ is achieved using a supertetrahedral cluster-constructed ion exchanger CdSnSe-2K, whose soft Se component and micro-porosity synergistically contribute to the enhancement in adsorption rate, selectivity and acid resistance.

Structural Evolution of Cadmium Selenide Clusters: An Unbiased Global Optimization Study of (CdSe)N for 5 ≤ N ≤ 80.

The structures of large cadmium selenide clusters are poorly understood due to the presence of challenging long-range Coulombic interactions and a vast number of possible structures. In this study, we present an unbiased fuzzy global optimization method that incorporates atom-pair hopping, ultrafast shape recognition, and adaptive temperatures within a directed Monte Carlo framework to enhance the search efficiency of binary clusters. Using this method and first-principles calculations, we successfully obtain the lowest-energy structures of (CdSe)N clusters with 5 ≤ N ≤ 80. The putative global minima reported in the literature have been obtained. The binding energy per atom tends to decrease with cluster size. Our results show that the stable structures evolve from rings to stacked rings, cages, nanotubes, cage-wurtzite, cage-core, and finally wurtzite structures, enabling us to reveal a systematic structural evolution for the growth of cadmium selenide clusters without ligands.

Absorption wavelength (TD-DFT) and adsorption of metal chalcogen clusters with methyl nicotinate: Structural, electronic, IRI, SERS, pharmacological and antiviral studies (HIV and omicron)

The DFT B3LYP-LAND2DZ technique is used to examine interactions of Methyl nicotinate with copper selenide and zinc selenide clusters. The existence of reactive sites is determined using ESP maps and Fukui data. The energy variations between HOMO and LUMO are utilised to calculate various energy parameters. The Atoms in Molecules and ELF (Electron Localisation Function) maps are employed to investigate the topology of the molecule. The Interaction Region Indicator is used to determine the existence of non-covalent zones in the molecule. The UV–Vis spectrum using the TD-DFT method and DOS graphs are used to obtain the theoretical determination of electronic transition and properties. Structural analysis of the compound is obtained using theoretical IR spectra. To explore the adsorption of copper selenide and zinc selenide clusters on the Methyl nicotinate, the adsorption energy and theoretical SERS spectra are employed. Furthermore, pharmacological investigations are carried out to confirm the drug's non-toxicity. The compound's antiviral efficacy against HIV and Omicron is demonstrated via protein-ligand docking.

Synthesis, photoluminescence and magnetism of a trimetallic selenide cluster: (BuSn)4Ga2Mn2O6(SeO3)6

A novel heterometallic organotin-oxo cluster (BuSn)4Ga2Mn2O6(SeO3)6 has been prepared by a hydrothermal reaction and its structure was determined by single-crystal X-ray diffraction. Such discrete butyltin-oxo selenide cluster doped with two cationic metals (Ga and Mn) has a narrow band-gap and shows promise for photocurrent conversion. Solid state variable temperature fluorescence spectra show the increased intensity and the blue-shift of the maximum emission peak from 435 to 430 nm with decreasing temperature. The doped transition metal endows the compound with ferromagnetic-like behavior.

Soluble Molecular Rhenium Cluster Complexes Exhibiting Multistage Terminal Ligands Reduction.

Substitution of terminal halide ligands of octahedral rhenium cluster complexes [Re6Q8X6]4- in a melt of 4,4'-bipyridine (bpy) led to us obtaining four new compounds with the general formula trans-[Re6Q8(bpy)4X2] (Q = S or Se; X = Cl or Br) in high yield. In contrast to most of the known molecular rhenium cluster complexes with heteroaromatic terminal ligands, compounds 1-4 are soluble in organic solvents. This made it possible to carry out a detailed characterization of the new compounds both in solids and in solutions. In particular, it was shown that compounds 1-4 in the DMSO solution exhibit four reversible reduction processes. A comparison of the obtained data with the results of DFT calculations of the electronic structure suggests that these processes correspond to two-electron reduction of all four bpy ligands. The reduction potentials are shifted to the positive region compared with the potential of free bipyridine, and the value of the shift depends on the composition of the cluster core. The presence of four transitions also suggests that electronic exchange between terminal ligands in the cis-position is possible. The study of the luminescence of the compounds showed that emission maxima of selenide clusters almost coincide with those of sulfide ones, while luminescence spectra of the complexes with chloride terminal ligands (1 and 3) are slightly blue-shifted relative to the spectra of the complexes with bromide ligands (2 and 4).

Dimensional Control of Assembling Metal Chalcogenide Clusters

The ability to synthesize novel functional materials at the nanoscale relies on the design and synthesis of versatile, tunable, atomically precise building blocks. Clusters of atoms exhibit physical properties beyond those of their constituent atoms, and new phenomena (e.g. electronic, magnetic) can emerge in such materials. This minireview describes a method to create site‐differentiated clusters and presents various synthetic approaches toward creating materials from these building blocks. The cobalt selenide clusters fundamental to this study are members of a larger class of clusters with the [M6E8] stoichiometry (M = metal, E = chalcogen). There are two ways to prepare suitably reactive [M6E8] monomeric clusters for bonded assemblies: (1) incorporating a secondary functionality on the capping ligand, and (2) introducing removable, reactive ligands on the cluster surface. Rationally designed chemical transformations give us precise control over the extent and dimensionality of the resulting materials. The new bottom‐up approaches towards extended solids presented in this minireview reveal how to build from 0‐dimensional building blocks into 1‐, 2‐, and 3‐dimensional systems that comprise clusters.

Dual-doped CdSe:Cu:O films grown by sputtering using CdSe–CuO composite targets

The effects of the simultaneous incorporation of Cu and O in CdSe films grown by sputtering are presented. The Cu and O contents varied between 1 and 5 at.% in films deposited at 150, 200, 250 and 300 °C. Concentrations of 2, 3, 4 and 5 at.% of CuO in the target promoted the formation of copper selenide clusters immersed within the CdSe:Cu:O host. Energy considerations (enthalpy of formation and bond dissociation energy) were used to discuss the absence of copper oxide and the formation of copper selenide aggregates, as well as the film thickness dependence on the concentration of CuO in the target. The band gap of the films ranged from 1.21 to 2.07 eV, depending upon growth conditions. Significant below-band-gap absorption was observed which was ascribed to the copper selenide micro and nano clusters. Good crystalline quality of the films, for high substrate temperatures, was evidenced through the appearance of overtones of the vibrational longitudinal optic modes detected by Raman micro spectroscopy. It was determined that the electronic properties, optical transmission and electrical conductivity depended on the chemical composition and crystalline structure. This characteristic is relevant because through copper and oxygen co-doping is possible to control these technologically important physical properties of CdSe in a simple and reliable manner.

Discrete Supertetrahedral T5 Selenide Clusters and Their Se/S Solid Solutions: Ionic-Liquid-Assisted Precursor Route Syntheses and Photocatalytic Properties.

Although supertetrahedral Tn sulfide clusters (n=2-6) have been extensively explored, the synthesis of Tn selenide clusters with n>4 has not been achieved thus far. Reported here are ionic-liquid (IL)-assisted precursor route syntheses, characterizations, and the photocatalytic properties of six new M-In-Q (M=Cu or Cd; Q=Se or Se/S) chalcogenide compounds, namely [Bmmim]12 Cu5 In30 Q52 Cl3 (Im) (Q=Se (T5-1), Se48.5 S3.5 (T5-2); Bmmim=1-butyl-2,3-dimethylimidazolium, Im=imidazole), [Bmmim]11 Cd6 In28 Q52 Cl3 (MIm) (Q=Se (T5-3), Se28.5 S23.5 (T5-4), Se16 S36 (T5-5); MIm=1-methylimidazole), and [Bmmim]9 Cd6 In28 Se8 S44 Cl(MIm)3 (T5-6). The cluster compounds T5-1 and T5-3 represent the largest molecular supertetrahedral Tn selenide clusters to date. Under visible-light illumination, the Cu-In-Q compounds showed photocatalytic activity towards the decomposition of crystal violet, whereas the Cd-In-Q compounds exhibited good photocatalytic H2 evolution activity. Interestingly, the experimental results show that the photocatalytic performances of the selenide/sulfide solid solutions were significantly better than those of their selenide analogues, for example, the degradation time of the organic dye with T5-2 was much shorter than that with T5-1, whereas the photocatalytic H2 evolution efficiencies with T5-3-T5-6 improved significantly with increasing sulfur content. This work highlights the significance of IL-assisted precursor route synthesis and the tuning of photocatalytic properties through the formation of solid solutions.

Inorganic clusters as metalloligands: ligand effects on the synthesis and properties of ternary nanopropeller clusters.

Redox-active multimetallic platforms with synthetically addressable and hemilabile active sites are attractive synthetic targets for mimicking the reactivity of enzymatic co-factors toward multielectron transformations. To this end, a family of ternary clusters featuring three edge metal sites anchored on a [Co6Se8] multimetallic support via amidophosphine ligands are a promising platform. In this report, we explore how small changes in the stereoelectronic properties of these ligands alter [Co6Se8] metalloligand formation, but also substrate binding affinity and strength of the edge/support interaction in two new ternary clusters, M3Co6Se8L6 (M = Zn, Fe; L(-) = Ph2PN(-)iPr). These clusters are characterized extensively using a range of methods, including single crystal X-ray diffraction, electronic absorption spectroscopy and cyclic voltammetry. Substrate binding studies reveal that Fe3Co6Se8L6 resists coordination of larger ligands like pyridine or tetrahydrofuran, but binds the smaller ligand CNtBu. Additionally, investigations into the synthesis of new [Co6Se8] metalloligands using two aminophosphines, Ph2PN(H)iPr (LH) and iPr2PN(H)iPr, led to the synthesis and characterization of Co6Se8LH6, as well as the smaller clusters Co4Se2(CO)6LH4, Co3Se(μ2-PPh2)(CO)4LH3, and [Co(CO)3(iPr2PN(H)iPr)]2. Cumulatively, this study expands our understanding on the effect of the stereoelectronic properties of aminophosphine ligands in the synthesis of cobalt chalcogenide clusters, and, importantly on modulating the push-pull dynamic between the [Co6Se8] support, the edge metals and incoming coordinating ligands in ternary M3Co6Se8L6 clusters.

Variations in the Interplay of Intermetallic and Metal Chalcogenide Units in Organotin-Copper Selenide Clusters.

We report the formation and structures of two new organotin-copper selenide clusters that were obtained in a two-step procedure. First, [(R1Sn)4Se6] [R1 = CMe2CH2C(O)Me] is reacted with [Cu(PPh3)3Cl] and (SiMe3)2Se to form a bright-orange powder, the nature of which could not be identified in detail, yet a suspension of it in CH2Cl2 reacts with N2H4·H2O to afford single crystals of two cluster compounds, either [(Cu3Sn){(R2Sn)2Se4}2{(R2Sn2)Se3}] (1) or [(N2H4)(Cu4Sn){(R2Sn)2Se4}3] [2; R2 = CMe2CH2C(NNH2)Me]. Both are based on an intermetallic CuxSn cluster core (x = 3, 4), which is surrounded by organotin selenide units in different fashions. The results foster the assumption of a complex equilibrium to be present in according reaction mixtures.

Laser Ablation Generation of Bismuth Selenide Clusters from Mixtures of Elements, Crystalline Bi2Se3, or Thin Films: Laser Desorption Ionization (LDI) and Surface Assisted LDI Time-of-Flight Mass Spectrometry using Graphene and Nanodiamonds.

A bismuth-selenium system from mixtures of the powdered elements in various molar ratios and from Bi2Se3 crystals and/or thin films was studied using laser desorption ionization and surface assisted laser desorption ionization. The BimSen clusters were observed in both positive and negative ion modes, but the mass spectra were more intense, and also a higher number of clusters was formed in the positive ion mode than in the negative mode. The BiSen+ (n = 1-8), Bi2Sen+ (n = 1-5), and Bi3Sen+ (n = 1-6) clusters were detected. Similarly, in the negative ion mode, BiSen- (n = 2-9) and Bi2Sen- (n = 1-2) clusters were observed. In addition, the formation of Bim+ (m = 1-5), Sen+ (n = 1-8), and Sen- (n = 1-7) clusters was also observed. In total, 33 clusters were generated, and 4 new bismuth selenide clusters that have not been reported before (namely, BiSe7+/-, BiSe8+/-, BiSe9-, and Bi2Se5+) were detected. The formation of similar clusters was also observed from bismuth-selenium mixtures and from crystalline Bi2Se3. Furthermore, the Bi2Se3 thin films prepared from a magnetron sputtering technique were also examined via laser desorption ionization. The generation of clusters from the surface of graphene and nanodiamonds was also studied, but no remarkable difference with comparison to the metal surface was observed.

Gallium selenide clusters generated via laser desorption ionisation quadrupole ion trap time-of-flight mass spectrometry.

Gallium selenide thin films important for electronics and phase-change materials are prepared via pulsed laser deposition (PLD); however, there are no studies concerning the analysis of gallium selenide clusters formed in the gas phase. Laser desorption ionisation (LDI) combined with time-of-flight mass spectrometry (TOF-MS) has great potential to generate charged Gam Sen clusters, to analyse them and thus to develop new materials. LDI of Ga-Se mixtures using a pulsed laser (337 nm nitrogen) was used to generate gallium-selenide clusters. Mass spectra were recorded (in positive and negative ion mode) on a TOF mass spectrometer equipped with a quadrupole ion trap and reflectron mass analyser. Ga-Se mixtures were found to be suitable for laser ablation synthesis (LAS) of gallium selenide clusters, although their composition was strongly dependent on the laser energy. The effect of laser energy on the stoichiometry of the generated clusters was established. In total, over 100 gallium selenide Gam Sen clusters were generated and identified from Ga-Se mixtures. LDI of Ga2 Se3 crystals showed almost the same clusters up to m/z 1000 with lower intensities, whereas no clusters from Ga2 Se3 were observed above m/z 1000. A family of over 100 gallium selenide clusters, generated and identified for the first time, shows rich and complex chemistry. Some of the clusters represent new compounds that have the potential to be used in the development of advanced materials.

Laser Ablation Generation of Antimony Selenide Clusters: Laser Desorption Ionization (LDI) Quadrupole Ion Trap Time of Flight Mass Spectrometry.

The binary system Sb-Se was studied via laser ablation using antimony-selenium mixtures made from powdered elements in various ratios generating new SbmSen clusters. The results show that in addition to Sbm+ (m =1-8) and Sen+ (n = 2-9) clusters, a series of SbmSen+ clusters such as SbSe1-8+, Sb2Se1-6+, Sb3Se1-5+, Sb4Se1-3+, and Sb5Se1,2+ is generated. In addition, some low intensity oxidized clusters like Se6O2+, Se7O2+, and SbSe2-6O5+ and partially hydroxylated clusters (SbSeO2H7+, SbSe5O4H+) are also formed. In total, 24 new antimony selenide clusters were generated. The knowledge gained can contribute to the elucidation of the structure of SbmSen glasses. Graphical Abstract.

Chalcogenide-capped triiron clusters [Fe3(CO)9(μ3-E)2], [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] and [Fe3(CO)7(μ3-E)2(μ-dppm)] (E = S, Se) as proton-reduction catalysts

Chalcogenide-capped triiron clusters [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] and [Fe3(CO)7(μ3-E)2(μ-dppm)] (E = S, Se) have been examined as proton-reduction catalysts. Protonation studies show that [Fe3(CO)9(μ3-E)2] are unaffected by strong acids. Mono-capped [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] react with HBF4.Et2O but changes in IR spectra are attributed to BF3 binding to the face-capping carbonyl, while bicapped [Fe3(CO)7(μ3-E)2(μ-dppm)] are protonated but in a process that is not catalytically important. DFT calculations are presented to support these protonation studies. Cyclic voltammetry shows that [Fe3(CO)9(μ3-Se)2] exhibits two reduction waves, and upon addition of strong acids, proton-reduction occurs at a range of potentials. Mono-chalcogenide clusters [Fe3(CO)7(μ3-CO)(μ3-E)(μ-dppm)] (E = S, Se) exhibit proton-reduction at ca.-1.85 (E = S) and -1.62 V (E = Se) in the presence of p-toluene sulfonic acid (p-TsOH). Bicapped [Fe3(CO)7(μ3-E)2(μ-dppm)] undergo quasi-reversible reductions at -1.55 (E = S) and -1.45 V (E = Se) and reduce p-TsOH to hydrogen but protonated species do not appear to be catalytically important. Current uptake is seen at the first reduction potential in each case, showing that [Fe3(CO)7(μ3-E)2(μ-dppm)]- are catalytically active but a far greater response is seen at ca.-1.9 V being tentatively associated with reduction of [H2Fe3(CO)7(μ3-E)2(μ-dppm)]+. In general, selenide clusters are reduced at slightly lower potentials than sulfide analogues and show slightly higher current uptake under comparable conditions.

Two Unique Crystalline Semiconductor Zeolite Analogues Based on Indium Selenide Clusters.

Developing the structural diversity of microporous zeolitic frameworks with integrated semiconducting properties is promising but remains a challenge. Reported here are two unique crystalline semiconductor zeolite analogues constructed from two kinds of indium selenide clusters with augmented ctn and zeolite-type sod networks. The intrinsic semiconducting nature in these In-Se domains gives rise to pore-size-dependent and visible-light-driven photocatalytic activity for organic dye degradation.

Formation and Structural Diversity of Organo-Functionalized Tin-Silver Selenide Clusters.

When reacting the organic functionalized tin selenide clusters [(SnR1 )3 Se4 Cl] (A, R1 =CMe2 CH2 C(O)Me) or [(SnR1 )4 Se6 ] (B) with (SiMe3 )2 Se and [Ag(PPh3 )3 Cl] at -78 °C in CH2 Cl2 , a microcrystalline intermediate (compound 1) precipitates, which was investigated by magic angle spinning (MAS) NMR spectroscopy, powder X-ray diffraction (PXRD), energy dispersive X-ray (EDX) spectroscopy, and quantum chemistry calculations, to derive information about its composition and structure. Compound 1 re-dissolves under reorganization into the organo-functionalized Ag/Sn/Se cluster compound [Ag6 (μ6 -Se)(Ag8 Se12 ){(R1 Sn)2 Se2 }6 ] (2), or the mixed-valence cluster [(AgPPh3 )2 (SnII Cl)2 Se2 {(R1 SnIV )2 Se2 }2 ] (3), depending on the presence or the exclusion of daylight, respectively. The addition of N2 H4 ⋅H2 O to a solution of 1 yields selectively [Ag7 (μ7 -Se)(Ag7 Se12 ){(R2 Sn)2 Se2 }6 ] (4, R2 =CMe2 CH2 C(N2 H2 )Me), the Ag/Sn/Se core of which is isomeric to that of 2. 2-4 were characterized by X-ray diffraction. NMR spectroscopic studies on solutions of 1 indicate the co-existence of different species.