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Epitaxial growth of SnSe was studied using pulsed laser deposition on three kinds of singlecrystalline substrates, MgO (100), NaCl (100), and SrF2 (100), along with silica glass. For polycrystalline SnSe grown on glass, we found that a 20% Se-rich polycrystalline target is effective for obtaining stoichiometric SnSe films. The crystal structure of all the obtained films was the same as that of bulk SnSe, and the optimum temperatures for epitaxial growth were 400-500 °C, where the highest temperature was limited by re-evaporation. All the epitaxial films exhibited an a-axis orientation. For in-plane epitaxial structures, a quasi cube-on-cube heteroepitaxy was observed for MgO, whereas a 45°-rotated heteroepitaxy was observed for NaCl and SrF2, which can be explained by in-plane lattice matching. The anisotropic lattice mismatching and thermal expansion explain the compressive strain induced along the in-plane c-axis and the tensile strains along the in-plane b-axis and the out-of-plane a-axis. The epitaxial films on NaCl exhibited the best crystallinity, but the highest hole mobility of 60 cm2/(V s) was obtained on MgO. The indirect optical gap of the best films was determined to be 0.8 eV. Plausible interface models were proposed based on density functional calculations. [ABSTRACT FROM AUTHOR]

Reaction of SeO2, tetramethylammonium (TMA) chloride, aqueous HCl and Cl2 yields oxochloroselenate with incorporated Cl2 units, TMA3{[Se2O2Cl7](Cl2)}. The main feature of this compound is the strong (up to 3.5 kcal mol−1, according to DFT calculations) Cl⋅⋅⋅Cl bonding, which is also detected by Raman spectroscopy. [ABSTRACT FROM AUTHOR]

In this paper, two new complexes of selenium caffeine, [Se(Caf)4], and zinc α-tocopherol, [Zn(α-Tpl)2(NO3)2], are synthesized. The structures of complexes are characterized by IR, Raman and 1H NMR spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and thermogravimetric (TG/DTG) analysis. According to conductivity measurements the complexes are non-electrolytes. Spectroscopic studies of Se0 caffeine complex indicate its monodentate coordination via nitrogen atom N9 at 1: 4 molar ratio metal-to-ligand. In [Zn(α-Tpl)2(NO3)2], α-Tpl chelate is coordinated as a monodentate ligand via oxygen atom of the hydroxyl group with 1: 2 metal-to-ligand molar ratio. The percentage scavenging activity of hydroxyl radical (IC50 = 0.21 and 0.32 µg/mL), DPPH (0.17 and 0.30 µg/mL) and superoxide anion scavenging activity (0.18 and 0.32 µg/mL) indicate that selenocaffeine complex is of higher potential antioxidant activity than zinc(II) α-tocopherol complex. [ABSTRACT FROM AUTHOR]

Abstract We describe herein the use of arylselanylpyrazole–copper complexes as versatile catalysts for C Se and C S coupling reactions. The performance of these complexes for C Se reactions was investigated in chalcogenoacetylene synthesis. The reactions were carried out under mild and aerobic conditions and afforded selanylalkynes bearing a variety of electron-withdrawing and electron-donating groups. The performance of these catalysts for C S coupling was investigated through the reaction of aryl halides with thiols and products were obtained in moderate to excellent yields. A plausible mechanism for selenoacetylene synthesis is also suggested, and the 77Se NMR results show that these arylselanylpyrazole ligands act as hemilabile ligands. High-resolution mass spectrometry was used to investigate the intermediates and also to corroborate the proposed catalytic cycle. Graphical abstract Unlabelled Image Highlights • Versatile catalytic system for carbon‑selenium and carbon‑sulfur bond formation. • Arylselanylpyrazole as hemilabile ligand for copper. • A copper complex for coupling reaction under aerobic condition. • Tolerate a wide vary of functional groups, even examples as nitro, amino and methoxy. [ABSTRACT FROM AUTHOR]

Abstract The electrochemical performance of nanostructured nickel-cobalt sulfides is greatly limited by the sluggish reaction kinetics and limited electroactive sites. Herein, we design and synthesize free-standing Se doped nickel-cobalt sulfides with controllable-component directly on carbon cloth, which involves the hydrothermal process and sulfuration/selenylation reaction. Serving as free-standing electrode, as-synthesized Se doped nickel-cobalt sulfides not only favor the fast ion diffusion path and low contact resistance, but also provide rich electroactive sites with electrolyte. More importantly, proper Se doping in nickel-cobalt sulfides greatly increases the electrochemically active surface area and reduces the charge transfer resistance. Based on the X-ray photoelectron spectroscopy and transmission electron microscopy results, the reaction mechanism is convincingly revealed that Se dopants have been changed into SeO x. And electrochemical activated oxyhydroxides are mainly involved in electrochemical reactions. As a result, as-fabricated Se doped nickel-cobalt sulfides show a good electrochemical performance for supercapattery. Further, the supercapattery device is also assembled by using nickel-cobalt sulfide/selenide as positive electrode and activated carbon as negative electrode, which shows a high energy density of 39.6 Wh kg−1 at the power density of 1501 W kg−1. Graphical abstract Image 1 Highlights • Se doping can provide large the active sites and fast electron transport path. • The Se doped nickel-cobalt sulfides show good electrochemical performances. • The NiCo 2 S 2.2 Se 1.8 //AC device shows a high energy density of 39.6 Wh kg−1. [ABSTRACT FROM AUTHOR]

Graphical abstract Gram scale SnSe nanomaterials having rod shaped morphology with aspect ratios of ∼5 has been prepared by exploiting a simple wet-chemical route at ambient environment within a short time without need of any inert atmosphere. The pristine SnSe pellets are p-type, and showed slightly higher electrical conductivities compared to those of single crystalline SnSe. Subsequent Bi doping via high energy ball milling process convert p-type SnSe to n-type SnSe. The thermal conductivity of our polycrystalline SnSe was found in between those of single crystalline SnSe along a- and b-axis (or c-axis) direction. Highlights • Synthesized doped and undoped SnSe nanomaterials at ambient conditions. • The SnSe nanorods having aspect ratios of ~5. • The synthesized SnSe nano-rods used as potential materials for thermoelectric applications. • The pristine SnSe pellets are p-type, and showed slightly higher electrical conductivities compared to those of single crystalline SnSe. • The counterpart n-type SnSe pellets were synthesized by doping Bi and their thermal conductivity was found to be between those of single crystalline SnSe along a- and b-axis (or c-axis) direction. Abstract Gram-scale SnSe nanomaterials have been prepared by exploiting a simple wet-chemical route at ambient environments in which a transparent NaHSe solution was mixed with SnCl 2 and sodium ascorbate, followed by hydrothermal heating for 24 h. It is notable that phase-pure crystalline SnSe nanorods having aspect ratios of ∼5 were obtained within a short period of time and without any sophisticated instruments or inert environment. The key steps and conditions to obtain pure SnSe nanorods in the synthesis process were identified and discussed. The SnSe powder was sintered using a facile spark plasma sintering method to form polycrystalline pellets for thermoelectric property measurements. According to the thermopower measurement results, the pristine SnSe pellets are p-type, and showed slightly higher electrical conductivities compared to that of single crystalline SnSe. The counterpart n-type SnSe pellets were also fabricated by doping Bi with a high energy ball milling process. The thermal conductivity of our polycrystalline SnSe was found to be in between that of single crystalline SnSe along a- and b- axis (or c-axis) direction. The facile and new synthesis route, high reproducibility and cost-effectiveness are easily adaptable for the formation of other doped and un-doped metal selenide nanomaterials with a short reaction time for various applications beyond thermoelectrics. [ABSTRACT FROM AUTHOR]

The reactions of the trimethylsilylpropargylidyne [W(≡CC≡CSiMe3)(CO)2(Tp*)] (1: Tp* = hydrotris(dimethylpyrazolyl)borate) towards selenium centred reagents when treated with tetrabutylammonium fluoride (TBAF) were explored in order to prepare alkynylselenolato propargylidynes, e.g., [W(≡CC≡CSePh)(CO)2(Tp*)]. Treating 1 with TBAF and PhSeSePh resulted in E and Z isomers of the vinylcarbyne (allylidyne) complex [W{≡CC(SePh)=CHSePh}(CO)2(Tp*)] in addition to traces of the trisubstituted derivative [W{≡CC(SePh)=C(SePh)2}(CO)2(Tp*)]. Reactions with PhSeCl resulted in the isolation of bimetallic bis-substituted allylidyne complex [(Tp*)(CO)2W≡CC(SePh)=C(SePh)C≡CC≡W(CO)2(CO)2(Tp*)] as well as the desired selenolatopropargylidyne [W(≡CC≡CSePh)(CO)2(Tp*)]. [ABSTRACT FROM AUTHOR]

Se 2 −2 (generated insitu by NaBH 4 reduction of Se) on reaction with 1-(2-chloroethyl) piperidine hydrochloride under N 2 atmosphere resulted in bis(1-(ethyl) piperidine) diselenide (L) as an orange solid. It’s bimetallic complexes having the formula [Zn 2 Cl 4 L ] (1), [Cd 2 Cl 4 L] (2) and [Cd 2 Br 4 L] (3) were also synthesized. L and its complexes 1 – 3 were characterized on the basis of physico-chemical and spectral (FT-IR, Mass, 1 H, 13 C, DEPT and 77 Se NMR) studies. IR spectroscopy revealed that M (II) ions (zinc and cadmium) are coordinated through selenium and nitrogen forming a five membered ring around M (II) ions. Elemental analysis measurement along with 1 H, 13 C, DEPT and ESI mass data confirmed the tetradentate mode of coordination of the ligand L. Moreover the coordination from selenium atom is also supported by the downfield shift of signal in 77 Se NMR spectroscopy. Powder XRD diffraction pattern reveals the crystalline nature of Ligand L and complexes 1 – 3 . Heteroditopic ligand L (N, Se, Se, N) ligates through both selenium and nitrogen atoms to two respective metal halides in complexes 1 – 3 , thus forming bimetallic complexes. Using DFT-based optimization of structures, the HOMO-LUMO energy gaps and molecular electrostatic potential surface of ligand L and complexes 1 – 3 were theoretically calculated at the B3LYP/LANL2DZ level of theory. These complexes adopt distorted tetrahedral geometry around M (II) ions as revealed by bond angles. HOMO-LUMO energy gap was calculated which allowed the calculation of relative properties like chemical hardness, chemical inertness, chemical potential, nucleophilicity and electrophilicity index of the synthesized products. The experimentally obtained IR and NMR results showed a good correlation with those of the theoretical ones. Ligand L and complex 1 – 3 displayed significant antibacterial and antifungal activity. [ABSTRACT FROM AUTHOR]

New series of trans - and cis -3-methylseleno substituted β-lactams ( 4 , 5 ) have been prepared from 2-methylselenoethanoic acid ( 2 ). The four-membered β-lactam ring was introduced by the condensation reaction between ketene retrieved from 2-methylselenoethanoic acid ( 2 ) and suitably substituted imines ( 3a-f) in the presence of triethylamine using POCl 3 in refluxing toluene. The structural and stereochemical analysis of novel trans - and cis -3-methylseleno substituted β-lactams were carried out using IR, NMR ( 1 H and 13 C), 2D-NMR ( 1 H– 1 H COSY, 1 H– 13 C HSQC), elemental analysis (CHN) and mass spectrometry (EIMS). Further, the structures of trans -1-(4′-methoxyphenyl)-3-methylseleno-4-(4′-chlorophenyl)azetidin-2-one ( 4b ), trans -1-(4′-methoxyphenyl)-3-methylseleno-4-(4′-methylphenyl)azetidin-2-one ( 4c ), trans - and cis -1-(4′-methoxyphenyl)-3-methylseleno-4-styrylazetidin-2-ones ( 4e and 5e ) were established by single crystal X-ray crystallographic studies. The cis or trans configuration of the hydrogen at C-3 was assigned with respect to C4-H. [ABSTRACT FROM AUTHOR]

A series of selenide nanoparticles (3 ± 1 nm sized platelet-like NiSe nanoparticles, uniform CuSe nanorods with a width of ∼12 nm and a length of 65 nm, and distorted ZnSe nano-hexagons with a side length of 12 ± 3.5 nm) were synthesized using a simple microwave irradiation technique using sodium selenite, hydrazine hydrate and starch as a selenide precursor, a reducing agent and a stabilizing agent, respectively. The morphologies and sizes of the as-synthesized nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. The interaction between this series of selenide nanoparticles (SNPs) and HSA was investigated using fluorescence and circular dichroism (CD) spectroscopy. The influencing factors such as the quenching type, binding stoichiometries, binding constants, and the free energy change determined using the fluorescence technique showed that SNPs spontaneously bound to HSA in a 1 : 1 ratio through non-fluorescent ground-state complex formation (static quenching mechanism). The binding constant values indicated that the binding forces were in descending order of NiSe ＞ CuSe ＞ ZnSe. The shift in the synchronous fluorescence spectra signified the involvement of the tryptophan moiety in the binding of SNPs with HSA. Based on the Förster theory of energy transfer, the distance between the donor (Trp residues) and the acceptor (SNPs) was obtained. Analysis of the far-UV and near-UV CD spectra of HSA suggested the effect of the SNPs on the secondary and tertiary structures of HSA. These investigations helped us to understand the interaction mechanisms between the nanoparticles and the protein molecule that interprets the pharmacokinetics of these nanoparticles while administering them as drugs. [ABSTRACT FROM AUTHOR]

Herein, Selenium (Se) nanoparticles are synthesized in the host matrix of a neat imidazolium based room temperature ionic liquid (RTIL) by a rapid and facile approach at mild conditions. From the microscopic imaging studies, the size of the nanoparticles was determined to be 45 ± 5 nm with globular morphology. XRD and TEM studies revealed the amorphous phase of the Se nanoparticles. This was further evident from the Raman mapping of the nanoparticles. Interestingly, the well-known amorphous to crystalline phase transformation of Se nanoparticles was found to be much slower (>2 months) in RTIL compared to few minutes-to-days as reported in earlier studies. The underlying mechanism for the formation of the nanoparticles and their phase stability has been explained taking into account of the structural and the fluidic aspects of the RTIL. [ABSTRACT FROM AUTHOR]

The wide anthropogenic use of selenium compounds represents the major source of selenium pollution worldwide, causing environmental issues and health concerns. Microbe-based strategies for metal removal/recovery have received increasing interest thanks to the association of the microbial ability to detoxify toxic metal/metalloid polluted environments with the production of nanomaterials. This study investigates the tolerance and the bioconversion of selenite (SeO 3 2− ) by the aerobically grown Actinomycete Rhodococcus aetherivorans BCP1 in association with its ability to produce selenium nanoparticles and nanorods (SeNPs and SeNRs). The BCP1 strain showed high tolerance towards SeO 3 2− with a Minimal Inhibitory Concentration (MIC) of 500 mM. The bioconversion of SeO 3 2− was evaluated considering two different physiological states of the BCP1 strain, i.e. unconditioned and/or conditioned cells, which correspond to cells exposed for the first time or after re-inoculation in fresh medium to either 0.5 or 2 mM of Na 2 SeO 3 , respectively. SeO 3 2− bioconversion was higher for conditioned grown cells compared to the unconditioned ones. Selenium nanostructures appeared polydisperse and not aggregated, as detected by electron microscopy, being embedded in an organic coating likely responsible for their stability, as suggested by the physical-chemical characterization. The production of smaller and/or larger SeNPs was influenced by the initial concentration of provided precursor, which resulted in the growth of longer and/or shorter SeNRs, respectively. The strong ability to tolerate high SeO 3 2− concentrations coupled with SeNP and SeNR biosynthesis highlights promising new applications of Rhodococcus aetherivorans BCP1 as cell factory to produce stable Se-nanostructures, whose suitability might be exploited for biotechnology purposes. [ABSTRACT FROM AUTHOR]

Abstract: Reported is the first example of a rhodium‐mediated β‐sulfide elimination, which represents a new mode of reactivity for late‐transition‐metal chemistry. This serendipitous discovery facilitates an ene‐cycloisomerization of allylic‐sulfide‐containing alkenylidenecyclopropanes (ACPs) to afford five‐membered carbo‐ and heterocyclic rings with concomitant intramolecular thioether migration. Interestingly, similar selectivity is obtained with both E‐ and Z‐allylic sulfides and the reaction is also feasible with an allylic selenide. Mechanistic studies are consistent with an inner‐sphere transfer of the sulfide, which is remarkable given the propensity for sulfides to poison transition‐metal catalysts. Finally, this type of atom‐economical rearrangement is envisioned to prompt the development of related processes given the utility of sulfides in target‐directed synthesis. [ABSTRACT FROM AUTHOR]

The emergence of transition metal dichalcogenides (TMD) as an exciting class of materials with appealing potentials in electronic and optoelectronics has drawn intensive attention in the past few years. Herein, we report the fabrication of NiSe 2 , which has been predicted to be a promising candidate in the field of electrocatalyst, by direct selenylation of the nickel substrate after epitaxial growth of selenium on a nickel foil. With a combination of photoelectron spectroscopy (PES), X-ray diffraction (XRD), scanning electron microscopy (SEM) and density function theory (DFT) calculations, it is possible to identify the phase transition among the previously reported stable Ni-Se phases and the ultimate formation of NiSe 2 species by external annealing at varying temperatures. While SEM reveals the morphology of NiSe 2 film with flat terraces, XRD, XPS and DFT calculations demonstrate that NiSe 2 is the relatively stable phase formed on the Ni substrate from the cohesive energy point of view. Furthermore, valence band spectra point out the nonmetallic level of these different Ni-Se compounds, agreeing well with literature reports. In the end, our report may indicate a feasible approach to synthesize the pure NiSe2 species under solution-free condition and an encouraging step forward towards non-noble electrocatalysts. [ABSTRACT FROM AUTHOR]

Selenium and silver nanobiocomposites were synthesized based on potentially metabolizable for microbes polysaccharides arabinogalactan and starch, as well as based on humic compounds obtained from peloids (therapeutic muds) and brown coals of Mongolia. Their influence on the phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus was studied. The absence of a negative effect of nanocomposite precursors (arabinogalactan, starch, and humic compounds) on the bacterial growth was demonstrated. All the nanocomposites studied were found to reduce the bacterial growth. Vital dyes were used to reveal that after 24 h of incubation, the examined nanobiocomposites caused changes in the morphology of the cells: the bacteria grew shorter and thicker, which led to their death. The nanoselenium composite in starch and the nanosilver composite in humic substances possessed the greatest effects. The results obtained indicate the presence of bacteriostatic and bactericidal effects in a number of nanocomposites studied. [ABSTRACT FROM AUTHOR]

Copper/palladium-catalyzed multicomponent cyclization reactions, which combine 2- gem-dibromovinyl aryl selenides with a nucleophilic source, were applied to the synthesis of 2-substituted benzo[ b]selenophenes. A systematic study of the cyclization system revealed that the mutual action between copper and palladium salts is essential for the formation of products in good yields, avoiding the formation of hydrogenated benzo[ b]selenophenes. The versatility of 2-bromobenzo[ b]selenophenes was also studied by palladium-catalyzed reactions with boronic acids, Grignard reagents and methyl acrylate affording the cross-coupled products in good yields. In addition, the reaction of 2-bromobenzo[ b]selenophene towards halogen-lithium exchange reactions followed by the addition of aldehyde afforded the corresponding secondary alcohol. [ABSTRACT FROM AUTHOR]

Herein, Selenium (Se) nanoparticles (NPs) have been synthesized in the host matrix of a neat room temperature ionic liquid (RTIL) via rapid, one-pot electron beam (EB) mediated approach. A dark red coloured solution was obtained, which exhibited absorption bands at 520, 620 and 730 nm. The Se NPs were predominantly amorphous, as was indicated from the XRD and TEM studies. This was further evident from the Raman mapping of the NPs. The NPs extracted from the RTIL showed assembling of the primary units (flake and spherical shaped) into an interconnected porous nanostructure. Interestingly, the well-known amorphous to crystalline phase transformation of Se NPs was found to be much slower (>2 months) in RTIL compared to few minutes-to-days as reported in earlier studies. Further, the interplay of dose rate was found to have significant impact on the morphology of the Se NPs. An equivalent dose of γ-ray irradiation (low dose rate) produces largely globular and less interconnected NPs. Based on the results obtained, it can be inferred that the RTIL simultaneously played the role of a solvent, a stabilizer and an in-situ source of radicals for the reduction of precursors. The underlying mechanism for the formation and subsequent morphological evolution of Se nanostructures in the two methods (EB and γ-irradiation) has been proposed, and was rationalized in the viewpoint of dose rate difference in addition to the existence of innate structural and fluidic aspects of the RTIL. [ABSTRACT FROM AUTHOR]

A calorimetric and thermodynamic investigation of three hydrous selenites, ZnSeO 3 ·2H 2 O, ZnSeO 3 ·H 2 O and CdSeO 3 ·H 2 O, was undertaken. All three phases were synthesized by mixing of aqueous solutions of zinc and cadmium nitrates, accordingly, and sodium selenite and characterized by XRD powder diffraction, energy dispersive X-ray microanalysis, inductively coupled plasma mass spectrometry and thermal analisys methods. The low-temperature heat capacity of ZnSeO 3 ·2H 2 O, ZnSeO 3 ·H 2 O and CdSeO 3 ·H 2 O were measured using adiabatic calorimetry between 5 and 324 K, and the third-law entropies were determined. Values of molar third law entropy S m °(298 K, ZnSeO 3 ·2H 2 O, cr.) = 179 ± 1 J·K −1 ·mol −1 , S m °(298 K, ZnSeO 3 ·H 2 O, cr.) = 150 ± 1 J·K −1 ·mol −1 , S m °(298 K, CdSeO 3 ·H 2 O, cr.) = 171 ± 1 J·K −1 ·mol −1 were calculated. The expanded uncertainties for S m ° are given at the 0.95 confidence level (k ≈ 2). The enthalpies of formation for ZnSeO 3 ·H 2 O, ZnSeO 3 ·2H 2 O and CdSeO 3 ·H 2 O were determined using H 2 SO 4 -solution calorimetry giving Δ f H m ° (298 K, ZnSeO 3 ·2H 2 O, cr) = −1238 ± 2 kJ·mol −1 , Δ f H m °(298 K, ZnSeO 3 ·H 2 O, cr) = −931 ± 2 kJ·mol −1 , Δ f H m °(298 K, CdSeO 3 ·H 2 O, cr) = −906 ± 2 kJ·mol −1 . The expanded uncertainties for Δ f H m ° are given at the 0.95 confidence level (k ≈ 2). The Gibbs energy of formation for ZnSeO 3 ·2H 2 O, ZnSeO 3 ·H 2 O and CdSeO 3 ·H 2 O at T = 298 K, 1 atm have been calculated on the basis on Δ f H m ° and Δ f S m °: Δ f G m °(298 K, ZnSeO 3 ·2H 2 O, cr.) = −1035 ± 2 kJ·mol −1 , Δ f G m °(298 K, ZnSeO 3 ·H 2 O, cr.) = −790 ± 2 kJ·mol −1 and Δ f G m °(298 K, CdSeO 3 ·2H 2 O, cr.) = −768 ± 2 kJ·mol −1 . The expanded uncertainties for Δ f G m ° are given at the 0.95 confidence level (k ≈ 2). Smoothed C p,m °( T ) values between T = 0 K and T = 320 K for ZnSeO 3 ·2H 2 O(cr.), ZnSeO 3 ·H 2 O(cr.) and CdSeO 3 ·H 2 O(cr.) are presented along with values for S m ° and the functions [ H m °( T ) − H m °(0)] and [ G m °( T ) − H m °(0)]. These results motivate a re-evaluation of the natural conditions under which selenites, and selenates replace selenides, and sulfides in the oxidation zones of sulfide ore deposits or upon weathering of technologic waste. The values of Δ f G° for ZnSeO 3 ·2H 2 O, ZnSeO 3 ·H 2 O and CdSeO 3 ·H 2 O were used to calculate the Eh–pH diagrams of the Zn–Se–H 2 O and Cd–Se–H 2 O, systems. These diagrams have been constructed for the average contents of these elements in acidic waters of the oxidation zones of sulfide deposits. The behavior of selenium, zinc, and cadmium in the surface environment have been quantitatively explained by variations of the redox potential and the acidity-basicity of the mineral-forming medium. Precisely these parameters determine the migration ability of selenium compounds and its precipitation in the form of various solid phases. [ABSTRACT FROM AUTHOR]

The chalcogenogallate RbGaSe2 was synthesized by thermal decomposition of rubidium azide in the presence of gallium selenide and selenium. RbGaSe2 crystallizes in the monoclinic space group C2/ c (no. 15) with the lattice parameters a = 10.954(1) Å, b = 10.949(1) Å, c = 16.064(1) Å, β = 99.841(4)°, V = 1898.2(2) Å3, and Z = 16 (single-crystal data, 20 °C) in the TlGaSe2 structure type. Its crystal structure features anionic layers 2∞[Ga4Se84-] with a van der Waals distance of 3.30(1) Å. Thermal analysis revealed a melting point of about 930 °C. Using UV/Vis diffuse reflectance spectroscopy, a wide bandgap of 3.16 eV was determined for the colorless semiconductor. The bonding situation in the compound was further compared with the isotypic cesium phases based on the results from Raman spectroscopy and DFT calculations. The slight shifts of the Raman bands suggest a slightly higher covalency of the rubidium compound. [ABSTRACT FROM AUTHOR]

Current work presents a facile, cost-effective, and green method to synthesize copper selenide nanostructures and copper selenide/graphene nanocomposites. The products were synthesized by a co-precipitation method by glycine amino acid as a green surfactant and graphene oxide (GO) sheets as a graphene source. X-ray diffraction patterns (XRD) of the products indicated that the products were Cu 2 Se 3 with tetragonal phase. Fourier transform infrared (FTIR) spectroscopy and the XRD patterns indicated that the GO sheets were changed into reduced GO (rGO) during the synthesis process. Scanning and transmission electron microscopy (SEM and TEM) images showed the nanoparticles (NPs) that were decorated on rGO sheets had the significantly smaller size in compared to the pristine NPs. UV-vis results revealed that, the absorption peak of the products were in the visible region with a band-gap value between 1.85 eV and 1.95 eV. Finally, the products were applied as photocatalytic materials to remove Methylene Blue (MB) dye under solar-light and visible-light irradiation conditions. It was observed; the rGO had a significant role in enhancing the photocatalytic performance of the products and Cu 2 Se 3 /rGO (15%) could degrade more than 91% and 73% of MB only during 1 h under solar-light and visible-light sources, respectively. [ABSTRACT FROM AUTHOR]

This paper describes a simple and reproducible solution phase synthesis approach for selenium nanoparticles by reducing selenium tetrachloride in the presence of ascorbic acid. An optimization study with poly (sodium 4-styrenesulfonate) produced stable and spherical narrowly size distributed nanoparticles (46 nm) which are considered highly monodisperse. The presence of selenium nanoparticles was confirmed by UV-visible spectroscopy for surface plasmon resonance (262 nm), elemental dispersive spectroscopy (11 KeV and 12.5 KeV) and size ranges characterized by dynamic light scattering (PDI = 0.04, size range of optimized nanoparticles = 35 nm to 75 nm), and visualized using scanning and transmission electron microscopy. [ABSTRACT FROM AUTHOR]

A one-pot, metal-free procedure has been developed to synthesize unsymmetrical organoselenides. In the first step of the reaction, arylation of potassium selenocyanate (KSeCN) with an iodonium reagent proceeds in the absence of a metal catalyst to produce an arylselenocyanate. In the second step, treatment with sodium borohydride unmasks a second selenium nucleophile that engages an aliphatic electrophile, iodonium reagent, or glycosyl halide. The procedure represents an umpolung approach to the synthesis of aryl-selenides. [ABSTRACT FROM AUTHOR]

The retro-Favorskii reaction is an excellent way to achieve terminal alkynes. Methodologies that connect the synthesis of terminal alkynes and organochalcogen motifs are important for the construction of novel compounds. Fourteen new terminal alkynes containing either Csp−S or Csp−Se bonds were selectively prepared through the retro-Favorskii reaction from the respective carbinol precursors. It was discovered that terminal chalcogen alkynes were stable for weeks if stored as a solution in hexanes. [ABSTRACT FROM AUTHOR]

Efficient and selective methods have been developed for the synthesis of previously unknown organyl [3-(trimethylsilyl)prop-2-yn-1-yl] selenides, organyl prop-2-yn-1-yl selenides, and bis[3-(trimethylsilyl) prop-2-yn-1-yl] selenide by reactions of 3-bromo-1-(trimethylsilyl)prop-1-yne with the corresponding organylselenolates and sodium selenide generated from diorganyl diselenides or elemental selenium by the action of sodium tetrahydridoborate. [ABSTRACT FROM AUTHOR]

A new series of vitamin E/selenated pyridine, vitamin E/selenated pyridazine, vitamin E/selenated coumarine and vitamin E/selenated nicotine moieties were synthesized and their cytotoxic activity is investigated using the human breast cancer cell line. The newly synthesized compounds were characterized using spectroscopic tools (IR,1H NMR,13C NMR, and mass spectroscopy) as well as microanalysis. Our study reveals that compound vitamin E/selenated nicotine moiety has the highest cytotoxic effect than the other synthesized compounds. [ABSTRACT FROM PUBLISHER]

In contrast to numerous thio- and selenocyanuric acid derivatives, sulfur- or selenium-containing s-heptazines have not been reported so far. Thio- and selenocyameluric acid esters were obtained by substitution reactions of s-heptazine chloride C6N7Cl3 with aromatic thiols and selenophenol; the resultant white or yellow solids were stable in air. They were comprehensively characterized by elemental analysis, 1H, 13C NMR, and IR spectroscopy. The thiocyameluric acid phenyl ester ( 1, C6N7(S(C6H5))3) and the corresponding selenium compound ( 7) formed co-crystals with mesitylene, which were analyzed by single-crystal X-ray diffraction. Both structures showed unusually large channels of ≈12 Å diameter. The thermal stability was measured by TGA (thermogravimetric analysis), and the flame retardancy of compound 1 was tested in PP by carrying out limiting oxygen index (LOI) measurements, which gave promising results. Quantum chemical calculations of the title compounds were performed to explain the observed properties and structural characteristics. [ABSTRACT FROM AUTHOR]

An atom-economical method for the synthesis of unsymmetrical diaryl selenides from arylhydrazines and stoichiometric amounts of diselenides was developed under mild conditions. The new and facile selenide synthesis involved the use of an inexpensive base in air to form unsymmetrical diaryl selenides in good yields. This C-Se radical arylation of diaryl diselenides was performed by forming aryl radicals from aryl-hydrazines under oxidative conditions. The formation of a phenyl radical was supported by trapping with 2,2,6,6-tetramethylpiperidine- 1-oxyl (TEMPO) in air. Therefore, this synthesis might involve a homolytic aromatic substitution (HAS) mechanism. The synthesis is both low costing and environmentally friendly and therefore, may be useful for the practical synthesis of unsymmetrical diaryl selenides. [ABSTRACT FROM AUTHOR]

Bismuth Selenide (Bi 2 Se 3 ) is a topological insulator (TI) with a structure consisting of stacked quintuple layers. Single crystal surfaces are commonly prepared by mechanical cleaving. This work explores the use of low energy Ar + ion bombardment and annealing (IBA) as an alternative method to produce reproducible and stable Bi 2 Se 3 surfaces under ultra-high vacuum (UHV). It is found that a clean and well-ordered surface can be prepared by a single cycle of 1 keV Ar + ion bombardment and 30 min of annealing. Low energy electron diffraction (LEED) and detailed low energy ion scattering (LEIS) measurements show no differences between IBA-prepared surfaces and those prepared by in situ cleaving in UHV. Analysis of the LEED patterns shows that the optimal annealing temperature is ~450 °C. Angular LEIS scans reveal the formation of surface Se vacancies when the annealing temperature exceeds 520 °C. [ABSTRACT FROM AUTHOR]

Reported here are two solvothermally synthesized metal selenides, namely [Cu 2 MSe 5 ][Mn(H + -en) 2 (en)] (M = Ge ( 1 ) and Sn ( 2 ), and en=ethanediamine). The two isostructural compounds feature a 1-D anionic chain of [Cu 2 MSe 5 ] 4- with the existence of strong Cu∙∙∙Cu interaction. The estimated optical band gap was determined to be 1.69 eV for 1 and 1.49 eV for 2 , indicating their semiconducting nature. Interestingly, 2 exhibits NIR-triggered photoelectric response, which make it potential semiconductor sensor used in photoelectric devices. [ABSTRACT FROM AUTHOR]

We investigated the amine-induced structure transformation of four selenidostannates, i.e. [Sn3Se7Fe(TEPA)]n (1), {[Sn2Se6]·4(H+-PR)} (2), {[Sn2Se6]·2[Fe(en)3]} (3), and {[Sn3Se7]n·2n(H+-DBN)} (4) (TEPA = tetraethylenepentamine, PR = piperidine, en = ethylenediamine, DBN = 1,5-diazabicyclo[4.3.0]non-5-ene), which were characterized by single-crystal X-ray diffraction and UV-vis spectroscopy. The TEPA-induced 1D chain structure of [Sn3Se7Fe(TEPA)]n in 1 can undergo cleavage of Se–Fe and Se–Sn bonds to form a 0D dimer unit of [Sn2Se6]2− observed in 2 and 3, induced by PR and en, respectively. More interestingly, under the induction of en and DBN templates, such a 1D chain can counterintuitively fuse into a 2D layered structure of [Sn3Se7]n2n− through the removal of [Fe(TEPA)] species and reformation of Sn–Se bonds. Moreover, these selenidostannates with different structural dimensionalities display photocurrent responses, which make them hold some promise as a potential semiconducting material applied in photoelectric devices. [ABSTRACT FROM AUTHOR]

Efficient and robust Earth-abundant catalysts for hydrogen evolution reaction (HER) is one of the key components for clean energy technologies aimed at reducing future carbon emissions. Here, an in-situ anion exchange approach to prepare hierarchical nanostructures consisting of ultrathin Cu 2-x Se nanosheet is reported. With the aid of the selenylation process and the hierarchical ultrathin nanostructure, the nanostructured Cu 2-x Se/Cu foam electrode achieved considerably enhanced HER performance with a large geometric current density of −100 mA cm −2 at a small overpotential of 313 mV and outstanding long-term operational stability. Significant improvement of electrocatalytic activity for Cu 2-x Se catalyst could be attributed to the promoted mass diffusion/transfer properties, which results from its special structural feature. Meanwhile, the overpotential associated with the catalyst/substrate interface could be effectively eliminated due to the self-supported construction. We believe that this work will lead towards the further development of Cu-based chalcogenides for applications in electrocatalysis and energy conversion. [ABSTRACT FROM AUTHOR]

New experimental data on the manifestation of hybridization and spin polarization effects in 3d-states of donor electrons of a low concentration of cobalt atoms in mercury selenide crystals are obtained. The Hall concentration and mobility of conduction electrons as a function of impurity concentration, and the temperature dependences of the electron mobility, specific heat, and elastic moduli at low temperatures, are investigated. A quantitative interpretation of the observed dependences based on an earlier-developed theory in a justified simplified model of a single localization peak in the electron density of states is performed. As a result, the hybridization parameters of the cobalt states are determined by consistently fitting the observed experimental dependences, and evidence for the spontaneous spin polarization of electrons in the temperature dependences of the impurity specific heat and impurity contribution to the elastic moduli is detected. [ABSTRACT FROM AUTHOR]

Chromium selenide (CrSe) crystalline thin film has been produced via chemical bath deposition on substrates (commercial glass). Transmittance, absorption, optical band gap and refractive index of the films have been examined by UV/VIS. Spectrum. Structural properties have been examined and XRD hexagonal form has been observed. The structural and optical properties of CrSe thin films, produced at different pH levels were analyzed; SEM and EDX analysis have been performed for surface analysis and elemental ratio of the films. It has been found that some properties of the films have been changed with pH and the changes of these properties with respect to pH have been investigated. Tested pH values were between 8 and 11. The optical band gap has been varied between 3.80 and 3.92 eV and film thickness has been changed from 76 nm to 126 nm for tested pH levels. Absorbance values were found to be 0.053, 0.018, 0.012 and 0.069 for pH values of 11, 10, 9 and 8, respectively (550 nm wavelength). The refractive index of CrSe thin films have been changed with film thickness, found as 2.27, 2.24, 2.25 and 2.26. [ABSTRACT FROM AUTHOR]

Thermoelectric figure of merit (ZT) of 0.14 at 200 K is achieved in p-type α-phase copper selenide (Cu 2 Se) parent compound made by a ball milling and hot pressing process which exhibits layered structure material. This figure of merit is higher than the conventional p-type TE material bismuth antimony at this temperature range. The broad maxima in the electrical resistivity data around 100 K indicates a possible charge density wave (CDW) transition and Peierls distortion, however, such kind of anomalies were not observed in other transport properties. These features suggest that p-type α-Cu 2 Se could be a promising thermoelectric material at low temperatures. [ABSTRACT FROM AUTHOR]

Two new non-centrosymmetric polar quaternary selenides, namely, RbZn4In5Se12 and CsZn4In5Se12, have been synthesized and structurally characterized. They exhibit a 3D diamond-like framework (DLF) consisting of corner-shared MSe4 (M=Zn/In) tetrahedra, in which the A+ ions are located. Both compounds are thermally stable up to 1300 K and exhibit large transmittance in the infrared region (0.65-25 μm) with measured optical band gaps of 2.06 eV for RbZn4In5Se12 and 2.11 eV for CsZn4In5Se12. Inspiringly, they exhibit a good balance between strong second harmonic generation (SHG) efficiency (3.9 and 3.5×AgGaS2) and high laser-induced damage thresholds (13.0×AgGaS2). Theoretical calculations based on density functional theory (DFT) methods confirm that such strong SHG responses originate from the 3D DLF structure. [ABSTRACT FROM AUTHOR]

A simple and efficient protocol to prepare divinyl selenides has been developed by the regio- and stereoselective addition of sodium selenide species to aryl alkynes. The nucleophilic species was generates in situ, from the reaction of elemental selenium with NaBH4, utilizing PEG-400 as the solvent. Several divinyl selenides were obtained in moderate to excellent yields with selectivity for the (Z,Z)-isomer by a one-step procedure that was carried out at 60 °C in short reaction times. The methodology was extended to tellurium, giving the desired divinyl tellurides in good yields. Furthermore, the Fe-catalyzed cross-coupling reaction of bis(3,5-dimethoxystyryl) selenide 3f with (4-methoxyphenyl)magnesium bromide 5 afforded resveratrol trimethyl ether 6 in 57% yield. [ABSTRACT FROM AUTHOR]

Reaction of cyrhetrenylphosphines, of general formula (η 5 -C 5 H 4 PR 2 )Re(CO) 2 L (R = Ph, L = CO ( 1 ); R = Cy; L = CO ( 2 ); R = Ph, L = PMe 3 ( 3 ) and R = Ph, L = P(OMe) 3 ( 4 )), with H 2 O 2 , BH 3 ·THF or selenium gives the respective cyrhetrenylphosphine oxides, boranes and selenides. These species were characterized by standard spectroscopic techniques (FT-IR, 1 H and 31 PNMR). Based on the 31 P 77 Se coupling constant ( 1 J P-Se ) of the phosphine-selenides, we established the following order of basicity of the parent cyrhetrenylphosphine 2 > 3 > 4 > 1 . We also confirmed the opposite electronic effects of the cyrhetrenyl and ferrocenyl groups attached to a –PR 2 unit. Finally, phosphine selenides 2c and 4c were structurally characterized by X-ray diffraction. [ABSTRACT FROM AUTHOR]

A novel method combining elemental sulfur and selenium was developed, yielding crystalline sulfur–selenium compounds. The compounds were melted, and an organic comonomer added. Once the organic comonomer was consumed, the viscous compound was vitrified and allowed to cool yielding organic–inorganic hybrid polymers that are termed Organically Modified Chalcogenide (ORMOCHALC) polymers. [ABSTRACT FROM AUTHOR]

The synthesis of a high-purity sample of the layered oxide selenide Sr 2 MnO 2 Ag 1.5 Se 2 is reported. At ambient temperature it crystallises in the space group I 4/ mmm with two formula units in the unit cell and lattice parameters a =4.08771(1) Å, c =19.13087(8) Å. The compound displays mixed-valent manganese in a formal oxidation state close to +2.5 and powder neutron diffraction measurements reveal that below the Néel temperature of 63(1) K this results in an antiferromagnetic structure which may be described as A-type, modelled in the magnetic space group P I 4/ mnc (128.410 in the Belov, Neronova and Smirnova (BNS) scheme) in which localised Mn moments of 3.99(2) μ B are arranged in ferromagnetic layers which are coupled antiferromagnetically. In contrast to the isostructural compound Sr 2 MnO 2 Cu 1.5 S 2 , Sr 2 MnO 2 Ag 1.5 Se 2 does not display long range ordering of coinage metal ions and vacancies, nor may significant amounts of the coinage metal readily be deintercalated using soft chemical methods. [ABSTRACT FROM AUTHOR]

A series of new mono and disubstituted alkylated and methoxylated benzisoselanzol-3(2H)-ones and bis(2- carbamoylaryl)diselenides were prepared in yields ranging from 55% to 95% starting from anthranilic acid and were evaluated for antiviral and antimicrobial activity. The compounds exhibited antiviral activity against Human herpes virus 1 and Encephalomyocarditis virus as well as antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Candida albicans. [ABSTRACT FROM AUTHOR]

Terpenyl alcohols, (-)-nopol and (-)-myrtenol were efficiently applied in the synthesis of new diselenides. The pinane skeleton, as the core of the structure, was decorated at the C-10 position by hydroxyl and O-trityl groups, and also OPh and SePh substituents connected to the C-10 carbon by -CH2- linker. The diselenides were transformed to electrophilic selenium reagents and tested in asymmetric methoxyselenenylation of styrene, and selenocyclization of o-allylphenol. [ABSTRACT FROM AUTHOR]

Nanotechnology strives to combine new materials for development of noble nanoparticles. As the nanoparticles exhibit unique optical, electronic, and magnetic properties depending on their composition, developing safe, cost-effective and environmentally friendly technologies for the synthesis have become an important issue. In this study, in vivo synthesis of europium selenide (EuSe) nanoparticles was performed using recombinant Escherichia coli cells expressing heavy-metal binding proteins, phytochelatin synthase and metallothionein. The formation of EuSe nanoparticles was confirmed by using UV–vis spectroscopy, spectrofluorometry, X-ray diffraction, energy dispersive X-ray and transmission electron microscopy. The synthesized EuSe nanoparticles exhibited high fluorescence intensities as well as strong magnetic properties. Furthermore, anti-cancer effect of EuSe nanoparticles against cancer cell lines was investigated. This strategy for the biogenic synthesis of nanoparticles has a great potential as bioimaging tools and drug carrying agents in biomedical fields due to its simplicity and nontoxicity. [ABSTRACT FROM AUTHOR]

Nano-selenium has a great potential to be used in chemical, biological, medical and environmental fields. Biological methods for nano-selenium synthesis have attracted wide interests, because they can be operated at ambient temperature and pressure without complicated equipments. In this work, a protozoa, Tetrahymena thermophila (T. thermophila) SB210, was used to in vivo synthesize nano-selenium. The biosynthesized nano-selenium was characterized using transmission electron microscopy, energy dispersive X-ray spectroscopy and Raman spectroscopy. The synthesized amorphous spherical selenium nanoparticles had diameters of 50–500 nm with the coexistence of irregular nano-selenium. The expressions of glutathione (GSH) synthesis related gene glutathione synthase , cysteine-rich protein metallothionein related gene metallothionein-1 and [2Fe-2S] cluster-binding protein related gene were up-regulated in the nano-selenium producing group. Also, the subsequent GSH detection and in vitro synthesis experimental results suggest the three proteins were likely to be involved in the nano-selenium synthesis process. [ABSTRACT FROM AUTHOR]

A simple synthesis method to prepare pure SnSe2 nanosheet anodes for Na ion batteries is reported. The SnSe2 2D sheets achieve a stable and reversible specific capacity of 515 mA h g‐1 after 100 cycles, with excellent rate performance. The sodiation and desodiation process in this anode material is shown to occur via a combination of conversion and alloying reactions. [ABSTRACT FROM AUTHOR]

Nitrogen doped carbon tubes (N-CT) of dia 100 nm are prepared by carbonization of polyaniline tubes and selenium impregnation into N-CT is carried out by melt diffusion process. The N-CT possess micropores and small mesopores that assist in trapping Se. Interestingly, Se absorption in micropores creates steric hindrance for the formation of long chain polyselendes during electrochemical discharge and hence leads to direct formation of Li 2 Se. Whereas, the small mesopores ensure proper electrode-electrolyte contact rendering good rate capability. Due to the presence of small mesopores a small quantity of polyselenides may be formed during initial cycles, however the nitrogen present in the carbon matrix can help in controlling their dissolution by creating polarity. Hence, it is observed here that after few initial cycles, the multistep reaction between Li and Se has changed to a single step. This is supported by in-situ electrochemical analysis like differential capacity (dQ/dV) plots, cyclic voltammetry impedance analysis and ex-situ UV–vis spectroscopy. [ABSTRACT FROM AUTHOR]

The interaction of 1-alkynyl phosphine oxides, sulfides, and selenides with Me3Al and Et3Al under zirconocene catalysis was studied. It has been found that the pathway of the reaction of 1-alkynyl phosphine derivatives with Et3Al strongly depends on the nature of the substrate and the solvent. The ethylalumination takes place in the case of 1-alkynyl phosphine oxides in hexane solvent. The reaction of 1-hexynyl phosphine oxide with Et3Al failed when dichloromethane was used as a solvent. Zirconium-catalyzed reaction of 1-heptynyl phosphine sulfide with Et3Al proceeds as the cycloalumination followed by the desulfurization under the action of low-valent zirconium complexes. 1-Heptynyl phosphine selenide was subjected to full deselenation under the reaction conditions. [ABSTRACT FROM AUTHOR]

Novel tetrazole-based diselenides and selenoquinones were synthesized via azido-Ugi and sequential nucleophilic substitution (S N ) strategy. Molecular docking study into mammalian TrxR1 was used to predict the anticancer potential of the newly synthesized compounds. The cytotoxic activity of the compounds was evaluated using hepatocellular carcinoma (HepG2) and breast adenocarcinoma (MCF-7) cancer cells and compared with their cytotoxicity in normal fibroblast (WI-38) cells. The corresponding redox properties of the synthesized compounds were assessed employing 2,2-diphenyl-1-picrylhydrazyl (DPPH), glutathione peroxidase (GPx)-like activity and bleomycin dependent DNA damage. In general, diselenides showed preferential cytotoxicity to HepG2 compared to MCF-7 cells. These compounds exhibited also good GPx catalytic activity compared to ebselen (up to 5 fold). Selenoquinones 18 , 21 , 22 and 23 were selected to monitor the expression levels of caspase-8, Bcl-2 and Ki-67 molecular biomarkers. Interestingly, these compounds downregulated the Bcl-2 and Ki-67 expression levels and activated the expression of caspase-8 in HepG2 cells compared to untreated cells. These results indicate that some of the newly synthesized compounds possess anti-HepG2 activity. [ABSTRACT FROM AUTHOR]

Two new barium iron pnictide–selenides, Ba 2 FeSbSe 5 and Ba 2 FeBiSe 5 , were synthesized by a high-temperature solid-state route and their crystal structures were determined using single crystal X-ray diffraction. Both compounds are isomorphic to the high pressure phase Ba 3 FeS 5 and crystallize in the orthorhombic space group Pnma (No. 62) with cell parameters of a =12.603(2)/12.619(2) Å, b =9.106(1)/9.183(1) Å, c =9.145(1)/9.123(1) Å and Z =4 for Ba 2 FeSbSe 5 and Ba 2 FeBiSe 5 , respectively. According to differential scanning calorimetry, Ba 2 FePnSe 5 compounds exhibit high thermal stability and melt congruently at 1055(5) K (Pn=Sb) and 1105(5) K (Pn=Bi). Magnetic characterizations reveal strong antiferromagnetic nearest-neighbor interactions in both compounds resulting in an antiferromagnetic ordering at 58(1) K for Ba 2 FeSbSe 5 and 79(2) K for Ba 2 FeBiSe 5 . The magnetic interactions between Fe 3+ centers, which are at least 6 Å apart from each other, are mediated by superexchange interactions. [ABSTRACT FROM AUTHOR]

A mixed solvent of monoethanolamine and thioglycolic acid is successfully used to dissolve Se powder to prepare a highly reactive and soluble Se solution at room temperature in air. The as-prepared Se solution is very stable for more than half a year without any observed precipitation even in air. We used the Se precursor solution to synthesize various metal selenide nanomaterials such as Sb2Se3 nanorods, CuSe nanoplates and CuInSe2 nanocrystals by using a facile and environmentally-friendly triethylene glycol process. The structure, morphology, chemical composition and optical properties of the synthesized metal selenide nanomaterials are characterized. Moreover, the CuInSe2 nanocrystals are used to prepare ethanol-based colloidal ink and then deposited thin films by a dip-coating process. The synthesized CuInSe2 nanocrystal thin films are annealed at 550 °C in a selenizing atmosphere. A power conversion efficiency of 2.65% has been achieved by using the CuInSe2 thin films after selenization as a light-absorbing layer under AM 1.5 illumination. [ABSTRACT FROM AUTHOR]

A simple, efficient, and eco-friendly synthetic protocol has been developed for the preparation of diaryl selenium compounds. To the best of our knowledge, this is the first Letter on the use of selenium dioxide as selenium source for the synthesis of diaryl selenides. Compared with other selenium sources the new source SeO 2 gives an environment-friendly and low-cost synthetic route, which may be useful for large-scale synthesis. [ABSTRACT FROM AUTHOR]