Alkynes In Presence Research Articles

Combustion Synthesis of Nano CeO<sub>2</sub> and its Application as a Catalytic Agent in Peptidomimetics

An eco-friendly cerium oxide nanoparticle was prepared through a solution combustion system with a novel fuel plant seed source Albizzia richardiana. The synthetic technique involves the Albizzia richardiana plant seeds as a fuel and cerium nitrate as an oxidizer (basis of cerium) was added in stoichiometric quantity in a well washed silica crucible and stirred for several minutes until persistent uniform solution was made. Then the mixture was kept in a heat up heating chamber at 500 °C. After dehydration and decomposition of homogeneous solution, the obtained CeO2 nanoparticles were thoroughly characterized using FT-IR, XRD and SEM morphological analysis. The synthesized nano CeO2 was a better catalytic agent for the production of Nα-Fmoc/Cbz-keto-1,2,3-triazole equivalents through the three-constituent reaction between amino acyl chloride equivalents of Fmoc/Cbz-protected amino acids, phenyl acetylene and sodium azide. Keto-1,2,3-triazoles were set upon by refluxing amino acyl chlorides with NaN3 and phenyl acetylene in presence of CeO2 nano particles in methanol. After a simple workup, the desired products obtained were fully categorized by FTIR, HRMS, proton and 13C NMR techniques.

Fluoride Abstraction Induced by Tris(pentafluoroethyl)difluorophosphorane: A Convenient Way to Synthesize Cationic N-Heterocyclic Carbene- and Cyclic (Alkyl)(amino)carbene-Ligated Copper Alkyne and Arene Complexes.

We herein report the convenient synthesis of different N-heterocyclic carbene (NHC)- and cyclic (alkyl)(amino)carbene (cAAC)-ligated copper cations using the weakly coordinating tris(pentafluoroethyl)trifluorophosphate counterion (FAP anion, [(C2F5)3PF3]-). The reaction of the fluorido complexes [(carbene)CuF] (carbene = NHC, cAACMe) 2a-2f and the tris(pentafluoroethyl)difluorophosphorane (C2F5)3PF2 in the presence of alkynes or arenes led to fluoride transfer from Cu to the phosphorane with formation of the cationic transition metal complexes [(carbene)Cu(L)]+ and the weakly coordinating counteranion [(C2F5)3PF3]- (FAP). Using this method, the complexes [(IDipp)Cu(L)]+FAP- (IDipp = 1,3-bis(2,6-di-iso-propylphenyl)-imidazolin-2-ylidene; L = PhC≡CPh, 4d; PhC≡CMe, 5d), [(cAACMe)Cu(L)]+FAP- (cAACMe = 1-(2,6-di-iso-propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene; L = PhC≡CPh, 4f; PhC≡CMe, 5f), [(SIDipp)Cu(C6Me6)]+FAP- (6e), (SIDipp = 1,3-bis(2,6-di-iso-propylphenyl)-imidazolidine-2-ylidene), and [(cAACMe)Cu(C6Me6)]+FAP- (6f) have been synthesized and characterized. The complexes [(IDipp)Cu(C6Me6)]+FAP- (6d) and [(cAACMe)Cu(C6Me6)]+FAP- (6f) have been used as catalysts for the copper(I)-catalyzed cycloaddition of benzyl azide to terminal alkynes.

Atypical components in the composition of nepheline from rocks of the Khibiny massif according to IR spectroscopy data

Nepheline is one of the main rock-forming minerals of the rocks of the Khibiny alkaline massif. Nepheline composition changes depending on the crystallization temperature, which makes it an indicator of rock formation conditions. In addition, nepheline is one of the main concentrators of hydrocarbon gases. The study of nepheline from different rocks of the Khibiny massif by local IR spectroscopy with Fourier transformation (micro-FTIR) has revealed the presence of water and acetylene in its structure. The water content estimated according to the method of statistical quantitative determination of water in nominally anhydrous minerals varies in the range from 0 to 0.78 wt.%. The highest water content has been observed in high-temperature nepheline of early formations (foyaite of the central and outer parts of the massif), and the lowest – in relatively low-temperature nepheline of later rocks of the Main Ring Fault (urtite, apatite-nepheline rock and poikilitic (kalsilite)-nepheline syenite – rischorrite). The study reveals that water enters the structure of nepheline in the form of H2O molecules that occupy vacancies in the potassium sites. The water content in nepheline is controlled by the number of vacancies in its structure. The presence of acetylene has been determined on a qualitative level. Additional studies are required to assess its quantitative content.

Styrene thermal decomposition and its reaction with acetylene under shock tube pyrolysis conditions: An experimental and kinetic modeling study

Styrene is an important compound for polymer production and a key intermediate in gas-phase kinetics of polycyclic aromatic hydrocarbons (PAHs). For the first time, the pyrolysis of styrene with and without the presence of acetylene is investigated in a single-pulse shock tube coupled to gas chromatography and mass spectrometry. For each reaction system, quantitative speciation profiles are probed within the temperature range of 1100–1730 K, nominal pressure of 20 bar, and reaction duration of ∼ 4 ms. A kinetic model is built to simulate the results. The model explains how styrene is consumed under high-pressure pyrolytic conditions, how the secondary chemistry of intermediate products affect subsequent PAH formation, and how acetylene addition alters the reaction pathways. Throughout the temperature range, styrene breakdown is dominated by the bimolecular interaction between styrene and hydrogen atom, which produces benzene+vinyl or phenyl and ethylene through the stabilization of 2-phenylethyl and its subsequent dissociation. As a result, large amounts of phenyl accumulate, which react with styrene to form C14H12 species while simultaneously releasing H atoms through addition/elimination reactions. The reactivity of fuel consumption is preserved by the regeneration of H atoms as chain carriers. Several C14H10 compounds are formed as a result of the following breakdown of the C14H12 isomers, particularly stilbene, 1,1-diphenyl ethylene, and 9-methyl-9H-fluorene. The presence of acetylene as a co-reactant with styrene allows the Hydrogen-Abstraction-Acetylene-Addition (HACA) pathway to proceed from phenyl radical to enhance the production of phenylacetylene at very low temperatures and acenaphthylene. This hinders the formation of C14H12 isomers, exclusive products from pure styrene dissociation by competing with the styrene+phenyl routes.

Plastics as a reburning fuel: Pyrolysis at reburning temperatures and NO-reburning by simulated pyrolysis gas

Using waste plastics as a reburning fuel is promising for both reducing NOx emissions and managing plastic waste. To gain a better understanding of the chemistry involved in plastic reburning, pyrolysis products of different types of plastics at typical reburning temperatures (900–1200 °C) were investigated experimentally, and the reburning performance of simulated plastic pyrolysis gases was studied through experiments and chemical kinetic modeling. The plastics involved in the pyrolysis experiments included high-density polyethylene (HDPE), polypropylene (PP), polyamide 6 (PA6), and acrylonitrile–butadiene–styrene copolymer (ABS). HDPE exhibited the highest hydrocarbon gas yield (up to ∼ 70 wt% at 900 °C) while ABS had the lowest gas yield (<20 wt%) among the four plastics at the investigated temperatures. The hydrocarbon gas was composed mainly of methane, ethylene, and acetylene, with ethylene decreasing and acetylene increasing with temperatures rising from 900 to 1200 °C. Hydrogen cyanide was found to be the dominant gaseous nitrogen-containing compound for PA6 and ABS. Solid byproducts such as soot were generated at pyrolysis temperatures exceeding 1100 °C, leading to a reduction of the gas yield for all plastics. This indicates a potentially important contribution of heterogeneous NO reduction mechanisms during plastic reburning at high temperatures. Concerning the homogeneous NO reduction, reburning experiments using simulated plastic pyrolysis gases composed of methane, ethylene, and/or acetylene were carried out at 700–1200 °C in a flow reactor with an initial NO concentration of 1000 ppm and an excess air ratio λ of 0.7. Results for the simulated plastic pyrolysis gases showed NO reduction efficiencies ranging from 30 % to 46 % within the temperature range 950–1200 °C. The presence of acetylene in the simulated pyrolysis gas mixtures appears to facilitate NO reduction. A detailed chemical kinetic model applied to simulate the experiments gave a reasonable prediction of the NO reduction and revealed the important role of the ketenyl radical in removing NO.

Nickel catalyzed chemical vapor deposition grown carbon nanoforest for the efficient removal of potentially toxic chemicals from water

The present study demonstrates Ni-catalyzed growth of carbon nanoforest (CNF)-supported on activated carbon fiber (ACF) via a combination of three steps, viz., calcination, H2-reduction, and catalytic chemical vapour deposition (CCVD) in the presence of acetylene (C2H2) as the carbon source to grow CNF. The physicochemical properties of the material are evaluated by various characterization tools. Transmission electron microscopic (TEM) data confirm that the growth of CNF follows tip-growth mechanism. The material is further tested for its adsorption capacities towards two potentially toxic organic compounds such as 4-nitrophenol (4-NP) and methylene blue (MB) at variable pH values. The material shows excellent adsorption of 4-NP (maximum adsorption capacity of 325.80 mg/g at a pH value of 2) and MB (maximum adsorption capacity of 480.90 mg/g at pH = 12). The high adsorption of 4-NP may be ascribed to the strong π-π interactions between 4-NP and the adsorbent, whereas, excellent adsorption of MB may be attributed to the combined effects of negative surface charge, high surface area, and hydrophilic characteristics of the material. The maximum adsorption capacity data obtained for both 4-NP and MB systems in the present study are superior to most of the literature data. The synthesized material may be useful in the removal of several other potentially toxic organic and inorganic pollutants from water.

Synthesis of Vinyl Esters of Fruit Acids under High Pressure

This article describes a method for the synthesis of vinyl esters from fruit acids: malic, tartaric, citric and acetylene, as well as the results of a spectrophotometric analysis of the obtained compounds. Process conditions, product yields, and physicochemical properties of the resulting vinyl esters are given. The homogeneous catalytic reaction of vinylation of malic, tartaric and citric acids with acetylene has been studied and the formation of the corresponding vinyl esters has been proven. The mechanisms of vinylation reactions in the presence of acetylene are proposed. In the synthesis of vinyl ethers, the effect of pressure, temperature, and reaction time on the product yield was established.

Ambiphilic Behavior of Ge(II)-Pseudohalides in Inter- and Intramolecular Frustrated Lewis Pair Alkyne Addition Reactions.

The reaction of the germylene chloride (NacNac)GeCl (1, NacNac = CH{(CMe)(2,6-iPr2C6H3N)}2), phenylacetylene, and B(C6F5)3 gives the intermolecular frustrated Lewis pair (FLP) addition product 2. In this case, the Ge(II) center acts as a base. In contrast, the analogous reaction of germylene thiocyanate 3 reacts independently with B(C6F5)3 to give the germylene cation salt [(NacNac)Ge][SCNB(C6F5)3] 4. Subsequent in the presence of alkynes, the Ge(II) cation and γ-C of 4 act as a Lewis acidic and basic center, respectively, to affect the addition of alkynes, affording products [(NacNac)Ge(RCCR')][SCNB(C6F5)3] 5 and 6. Compound 4 also reacts with Me3SiCN to give the cyanide-bridged Ge/B species 7, which also reacts with phenylacetylene to give CN abstraction and intramolecular addition yielding the salt [(NacNac)Ge(PhCCH)][NCB(C6F5)3] 8. Despite the similarity of 1 and 3, DFT calculations show that the highest occupied molecular orbital (HOMO) of 1 is mainly located at the more sterically hindered germylene center, while the HOMO of 3 is located on the less sterically hindered NCS group, prompting markedly different FLP addition products.

Synthesis of 2‐Methyl‐pyran‐4‐ones through Reaction of Acetylketene with Terminal Acetylenes in Presence of Gold (I)

AbstractIn this study, 2,6‐trimethyl‐4H‐1,3‐dioxin‐4‐one compound, which is a source of Acetylketene, was reacted with terminal alkynes in presence of IPrAuCl (1,3‐Bis(2,6‐diisopropylphenyl‐imidazol‐2‐ylidene)gold(I) chloride) catalyst and a new synthesis method for 2‐methyl‐pyran‐4‐one compounds has been developed. It was observed that the yields were very low when this reaction was carried out without using a catalyst. However, 95 % yield was obtained when this reaction was performed in the presence of a IPrAuCl catalyst.

Different contributions of ammonia oxidizing archaea and bacteria to nitrification in soils amended with equivalent amounts of either ammonium-N or organic-N

Although considerable knowledge exists on the impact of crop residues on soil N availability, information about their impact on nitrification specifically is lacking. The unique physiologies of ammonia oxidizing archaea (AOA) suggests their activities might respond differently to crop residue amendment compared to ammonia oxidizing bacteria (AOB). An incubation study was conducted on two widely distributed Oregon agricultural silt loam soils of the Walla Walla (WW) and Woodburn (CC) series, amended with a fertilizer rate of 70 μg N g−1 soil in the form of (1) NH4+-N, (2) clover stems (C:N ~ 25), or (3) clover leaves (C:N ~ 13). NH4+ accumulation in the presence of acetylene, and the relative amounts of AOA and AOB activities, in the presence of the selective AOB inhibitor, 1-octyne, were examined over a 28-31d incubation. Nitrifying activity in the crop residue-amended WW soil matched the rate of ammonification and was predominately octyne-resistant suggesting that nitrifying activity was dominated by AOA. In CC soil, the relative contributions of AOA and AOB to emergent activities was influenced by the nature of the residue and in a soil specific manner. In leaf amended CC soil, AOB contributed the majority of initial nitrifying activity over 0-7d, with the contribution of AOA activity increasing post 7d to represent 100% of the total rate. In stem amended CC soil, emergence of nitrifying and ammonifying activities were delayed, but after 7d incubation AOA activity emerged at a rate greater than the accompanying rate of ammonification. In NH4+-N amended soils, AOB activity emerged quickly at rates greater than when N was supplied by residues. The response of AOA activity to NH4+-N was soil specific being immediate and at a greater rate than leaf residue supported activity in WW soil, whereas in CC soil, AOA activity was temporally delayed (as with residue treatment) and emerged at a rate similar to that supported by leaf residue. From a practical perspective, the findings of this study show that an application of 70 μg N g−1 soil as crop residues can prevent AOB driven nitrifying activity from reaching its potential compared to an inorganic NH4+-N application, and also suggest the potential of AOA activity to be modified by residues in a soil specific manner.

Cover Feature: Borane Adducts of Aromatic Phosphorus Heterocycles: Synthesis, Crystallographic Characterization and Reactivity of a Phosphinine‐B(C6F5)3 Lewis Pair (Chem. Eur. J. 7/2022)

The first crystallographically characterized phosphinine–borane adduct mimics frustrated Lewis-pair reactivity. In the presence of alkynes, alkenes and esters, a facile conversion to novel phosphinine-based species is achieved even at room temperature. Our results provide fascinating new perspectives for the future, particularly with respect to the activation of small molecules. More information can be found in the Research Article by T. Böttcher, C. Müller et al. (DOI: 10.1002/chem.202104135).

CuI/TMEDA Catalyzed Solvent Free Homo-Coupling Reaction of Terminal Alkynes towards the Synthesis of Buta-1,3-diynes

An efficient method for the synthesis of buta-1,3-diynes have been developed via copper(I) catalyzed homocoupling reaction of terminal acetylenes in presence of CuI and tetramethylethylenediamine (TMEDA) at 100 ºC for 3.0 h under solvent-free conditions. This efficient methodology allowed the homocoupling of five terminal alkynes in moderate to excellent yields.

Hydration of alkynes to ketones using cobalt ferrite magnetic nanocatalyst encrusted with gold nanoparticles

A magnetically recoverable gold nanocatalyst supported on the surface of cobalt ferrite nanoparticle has been synthesized. Initially, CoFe2O4 magnetic core was prepared by ultrasound assisted co-precipitation method which was further surface functionalized using 3-mercaptopropyltriethoxysilane. By a precipitation process, highly dispersed Au nanoparticles were loaded on the surface of the thiol-functionalized magnetic core. Au (0) magnetic nanocomposite thus synthesized was used as catalyst for hydration of alkynes. The nanocomposite showed excellent catalytic activity for hydration both the alkyl and aryl alkynes in presence of 2 wt% of the material to generate corresponding ketones under microwave irradiation. The new catalyst could be easily recovered using an external magnet and could be reused without significant change in its activity.

2+2] Cycloadditions with an Iron Carbene: A Critical Step in Enyne Metathesis.

Ruthenium carbenes, famously used in olefin metathesis, have impacted numerous research areas, ranging from synthesis to materials and biology. Although in the same group as ruthenium, iron carbenes showing similar reaction patterns have not been reported. Such targets are of high interest because the use of a sustainable metal would lead to a decreased cost, toxicity, and environmental impact of the corresponding compounds. Herein, we report the synthesis of an iron carbene complex, [{PC(sp2)P}Fe(N2)(PMe3)] ([PC(sp2)P] = (bis[2-(di-isopropylphosphino)phenyl]methylene), which is capable of performing [2+2] cycloaddition reactions in the presence of alkynes. Specifically, η3-vinyl carbenes are formed stoichiometrically through a [2+2] cycloaddition between the alkyne and the metal carbene. Additional reactivity of the η3-vinyl carbenes with alkynes yields a second insertion product containing a new iron carbene moiety.

Synthesis of vinyl iodide chain-end polymers via organocatalyzed chain-end transformation.

In the presence of alkynes (CH[triple bond, length as m-dash]C-R2), iodide chain-end polymers (Polymer-I) were successfully transformed to vinyl iodide chain-end polymers (polymer-CH[double bond, length as m-dash]CR2-I) in a single step via organocatalysis. This reaction is completely metal-free and easy to carry out without using special reagents or special conditions. The polymers encompassing polyacrylates and polymethacrylate, and additional functionalities (e.g., OH and CF3) were also incorporated into the R2 moiety. The obtained Polymer-CH[double bond, length as m-dash]CR2-I further served as a useful precursor for copper-catalyzed cross-coupling reactions with various thiols (R3-SH) to yield vinyl sulfide chain-end polymers (polymer-CH[double bond, length as m-dash]CR2-SR3) with various R3 moieties. Interestingly, under selected conditions, this organocatalysis also offered block-like copolymers containing a conjugated oligo-alkyne segment and a non-conjugated polyacrylate segment. Exploiting the unique structure, the block-like copolymer was used as an efficient dispersant of carbon nanotubes.

Determination of Transformer Oil Contamination from the OLTC Gases in the Power Transformers of a Distribution System Operator

Power transformers are considered to be the most important assets in power substations. Thus, their maintenance is important to ensure the reliability of the power transmission and distribution system. One of the most commonly used methods for managing the maintenance and establishing the health status of power transformers is dissolved gas analysis (DGA). The presence of acetylene in the DGA results may indicate arcing or high-temperature thermal faults in the transformer. In old transformers with an on-load tap-changer (OLTC), oil or gases can be filtered from the OLTC compartment to the transformer’s main tank. This paper presents a method for determining the transformer oil contamination from the OLTC gases in a group of power transformers for a distribution system operator (DSO) based on the application of the guides and the knowledge of experts. As a result, twenty-six out of the 175 transformers studied are defined as contaminated from the OLTC gases. In addition, this paper presents a methodology based on machine learning techniques that allows the system to determine the transformer oil contamination from the DGA results. The trained model achieves an accuracy of 99.76% in identifying oil contamination.

Machine Learning for Revealing Spatial Dependence among Nanoparticles: Understanding Catalyst Film Dewetting via Gibbs Point Process Models

We combine in situ environmental transmission electron microscopy (E-TEM) with automated image processing and statistical machine learning to uniquely formulate interpretable mathematical models and accurate simulation tools for complex nanoscale phenomena involving coupled physical and chemical processes and interactions that are otherwise hard to model. In particular, there is a need for a better understanding, characterization, and prediction of the proximity effects among dense populations of metal nanocatalysts as they form and evolve over time. Here, we leverage point process theory, a branch of statistical machine learning, to “learn” the spatial dependencies among ensembles of adjacent alumina-supported iron nanoparticles from a time sequence of E-TEM images. We construct a set of point process models to make statistical inferences about the nature of spatial dependencies that govern the rapid formation, or “popping” of nanoparticles during thin film dewetting, concomitant with metal reduction in the presence of acetylene at 750 °C. We show that nanoparticles exhibit strong dispersion behavior, i.e., new nanoparticles pop in dispersed locations at a predictable distance from their existing territorial neighbors. We also show that Gibbs point processes adequately describe the pairwise interactions underlying such time-dependent spatial variations. Further, we build on our machine-learned models to develop a computational simulation tool capable of producing accurate spatiotemporal simulations of nanoparticle formation at finer time resolutions and larger spatial domains than those of experimental observations. This is a much needed capability to overcome current limitations in computational methods supporting the design, analysis, and control of the collective behavior of nanocatalyst populations.

Biotransformation of the insensitive munition constituents 3-nitro-1,2,4-triazol-5-one (NTO) and 2,4-dinitroanisole (DNAN) by aerobic methane-oxidizing consortia and pure cultures.

We present the first report of biotransformation of 3-nitro-1,2,4-triazol-5-one (NTO) and 2,4-dinitroanisole (DNAN), replacements for the explosives 1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT), respectively, by methane-oxidizing cultures under aerobic conditions. Two consortia, dominated by Methylosinus spp., degraded both compounds with transient production of reduced NTO products, and non-stoichiometric production of reduced DNAN products. No release of inorganic nitrogen was observed with either compound, indicating that NTO and DNAN may be utilized as nitrogen sources by these consortia. The pure culture Methylosinus trichosporium OB3b also degraded both compounds. Degradation was observed in the presence of acetylene (a known inhibitor of methane monooxygenase; MMO) when methanol was supplied, indicating that MMO was not involved. Furthermore, studies with purified soluble MMO (sMMO) from OB3b indicated that neither compound was a substrate for sMMO. Degradation was inhibited by 2-iodosobenzoic acid, but not by dicoumarol, suggesting involvement of an oxygen- and dicoumarol-insensitive (nitro)reductase. These results indicate methanotrophs can aerobically degrade NTO and DNAN via one or more (nitro)reductases, with sMMO serving a supporting role deriving reducing equivalents from methane. This finding is important because methanotrophic bacteria are widely dispersed, and may represent a previously unrecognized route of NTO and DNAN biotransformation in aerobic environments.

Determination of N2O reduction to N2 from manure-amended soil based on isotopocule mapping and acetylene inhibition

The quantification of N2O reduction during denitrification is crucial to take measures reducing N2O emissions from arable soils. The analysis of site specific N2O isotopic composition may help to quantify the pathway of N2O reduction to N2 during denitrification process. In manure-amended soil (chicken manure, cow manure and sheep manure), N2O reduction was evaluated by examining the N2O emissions in the presence of acetylene (C2H2) and by analyzing the N2O isotopocule deltas. The results indicated that the three manures had no significant differences for the N2O emission rates and N2O isotopocule deltas. The extent of N2O reduction to N2 was 81–84% using the mapping of Δδ18O(N2O-H2O/N2O-NO3-) (different value of δ18O between the N2O and H2O or NO3−) vs. SP (15N site preference in N2O) and approximately 76% using C2H2 (10% v/v) inhibition method under 60% WFPS (water–filled pore space). Moreover, complete N2O reduction held η18OR and SPR (net isotopocule effect of N2O reduction to N2) values of −13.6‰ and −6.7‰, respectively. It was also found that oxygen exchange between N2O and soil water was approximately 92%. In summary, the mapping of Δδ18O(N2O-H2O/N2O-NO3-) vs. SP was very useful to distinguish the production and consumption pathways of N2O during denitrification. The extent of N2O reduction was underestimated by the C2H2 method. These results provide guidance in correcting the acetylene effect, which is important in evaluating the impact of manure on the N2O reduction.

Cu2O/reduced graphene oxide/TiO2nanomaterial: An effective photocatalyst for azide‐alkyne cycloaddition with benzyl halides or epoxide derivatives under visible light irradiation

Cu2O/reduced graphene oxide/TiO2(Cu2O/rGO/TiO2) photocatalyst was synthesized under ultrasonic irradiation. The nanomaterial was identified by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT‐IR) spectroscopy, UV–vis absorption, and inductively coupled plasma optical emission spectroscopy (ICP‐OES). The Cu2O/rGO/TiO2photocatalyst was utilized in “click” reaction for the preparation of 1,4‐disubstituted 1,2,3‐triazoles via one pot multicomponent reaction of benzyl halide or epoxide derivatives with alkynes in presence of NaN3and triethylamine under visible light irradiation. The “click” reaction was performed under mild conditions affording good to excellent yields of the triazole compounds using low catalyst loading in short reaction times. The nanocomposite was recovered and recycled for five successive runs without a major diminution in its catalytic performance.