The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• by means of UV–vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and transmission electron microscopy (TEM) analysis (see Supporting Information File 1). Concerning the chemical structure of the conjugate, the data reported in the literature were

• size of the nanoparticles dispersed in PBS was slightly larger compared to those in H2O, the hydrodynamic diameter was 246 ± 44 nm (Figure 4A, red). Moreover, TEM images (Figure 4B) showed that the nanoparticles of conjugate Dex-1b were quite polydisperse with a size comparable to the one obtained by

• . The stock solution was diluted 1:2 in ultra-HPLC water, and 1 μL of the solution was deposited on the top of the TEM grid and left dried at room temperature. Steady state fluorescence measurements were performed on a Fluorolog®-3 spectrofluorometer (Horiba-Jobin Yvon) using 1.0 × 1.0 cm quartz cuvette

Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

• Edgar Peris,
• Raúl Porcar,
• María Macia,
• Jesús Alcázar,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2020, 16, 1924–1935, doi:10.3762/bjoc.16.159

• confirmed that the SILLPs act as scavengers for the leached Pd species. Noteworthy, the larger palladium leaching did not lead to higher activities, suggesting that in absence of the SILLP some deactivation for the leached species was taking place. The TEM analysis of the polymers after the reactions showed

• slightly decayed to ca. 70% yield, corresponding to a productivity of 4.87 g of 7 × g Pd−1 × h−1. This level of productivity was maintained during at least five hours of continuous use. The TEM images of the polymeric systems after their use under continuous flow conditions revealed again the presence of

• catalytic mixtures. b) TOF values obtained at 15 minutes. Conditions: 1 equiv methyl 4-bromobenzoate (0.25 mmol), 2 equiv benzylzinc bromide (0.5 mmol, 1 mL of a 0.5 M solution in THF), 5 mol % Pd catalyst (0.0125 mmol) in dry THF (1 mL). N2 atmosphere. Yields calculated by GC and confirmed by 1H NMR. TEM

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• cycles. According to the TEM image obtained after the eigth cycle, the collapse of the catalyst was the reason for decreased activity of the catalyst at that stage. Gholinejad et al. reported the synthesis of copper ferrite nanoparticles-modified starch (CuFe2O4@starch, 131) as a highly reusable

Synthesis of 3-alkenylindoles through regioselective C–H alkenylation of indoles by a ruthenium nanocatalyst

• Abhijit Paul,
• Debnath Chatterjee,
• Srirupa Banerjee and
• Somnath Yadav

Beilstein J. Org. Chem. 2020, 16, 140–148, doi:10.3762/bjoc.16.16

• photolysis, was characterised by TEM (Figure S1, Supporting Information File 1), which showed polydispersed spherical particles of a size distribution mainly in the range of 10–25 nm, with a mean diameter of 15 nm. The size distribution of the particles from Figure S1, Supporting Information File 1, is

• presented in Figure S3, Supporting Information File 1. TEM–EDX confirmed the nanoparticles to be those of Ru (Figure S2, Supporting Information File 1). Further, the Ru nanoparticles were separated by centrifugation and characterised in more detail. The TEM analysis of the isolated Ru nanoparticles showed

• (101), (210), (103), and (200), corresponding to the interlayer spacings of 2.10, 1.38, 1.24, and 1.18 Å, respectively, could be identified for Ru(0), and the crystalline planes (200) and (221), corresponding to the interlayer spacings of 2.38 and 1.60 Å for RuO2, could be identified. The TEM–EDX

Influence of the cis/trans configuration on the supramolecular aggregation of aryltriazoles

• Sara Tejera,
• Giada Caniglia,
• Rosa L. Dorta,
• Andrea Favero,
• Javier González-Platas and
• Jesús T. Vázquez

Beilstein J. Org. Chem. 2019, 15, 2881–2888, doi:10.3762/bjoc.15.282

• and distilled before use. ECD was recorded in the range of 200–400 nm at room temperature by using 10 mm quartz cells. SEM images were taken by a TEM, JEOL JEM 1010 belonging to the Electronic Microscopy Service (SEGAI) of the University of La Laguna, Spain. Compounds 7f, 8f, 9, 10, 11, and 12 were

A photochemical determination of luminescence efficiency of upconverting nanoparticles

• Baptiste Amouroux,
• Clément Roux,
• Jean-Claude Micheau,
• Fabienne Gauffre and
• Christophe Coudret

Beilstein J. Org. Chem. 2019, 15, 2671–2677, doi:10.3762/bjoc.15.260

• after identification by TEM. Yet, this type of work has remained isolated. Moreover, in these conditions, the nanoparticles do not work in conditions close to their foreseen applications. As we became interested in the design of such nanoparticles [21], we envisioned a “chemical approach” of this

• knowing NYb the number of ytterbium per nanoparticle: NYb and NEr (NEr: number of erbium atom per particles) can be derived from the number of RE atoms per NP, itself computed from TEM and XRD measurements taking into account the nanoparticles size (volume ≈ 5400 ± 1000 nm3), unit cell volume (107.6 Å3

Targeted photoswitchable imaging of intracellular glutathione by a photochromic glycosheet sensor

• Xianzhi Chai,
• Hai-Hao Han,
• Yi Zang,
• Jia Li,
• Xiao-Peng He,
• Junji Zhang and
• He Tian

Beilstein J. Org. Chem. 2019, 15, 2380–2389, doi:10.3762/bjoc.15.230

• broad and strong absorption makes the 2D MnO2 nanosheets a potential energy acceptor for the fluorophores which are stacked on the nanosheets plane, leading to the fluorescence quenching through FRET mechanism [32][34]. The transmission electron microscopy (TEM) image of the prepared product revealed

• glycosheet which β-D-galactosides pointing away from the surface. Dynamic light scattering (DLS) exhibited a size of 198.6 nm for the 2D MnO2 nanosheets (Figure 2C), which was in accordance with the TEM characterization. The size of the photochromic Glyco-DTE@MnO2 glycosheet was determined as 255.4 nm

• absorbance spectrum and (B) high resolution TEM image of 2D MnO2 nanosheets (1 × 10−5 g/mL) in ultrapure water; (C) DLS and Zeta potential characterizations of 2D MnO2 photochromic glycosheet. (A) Emission spectral changes of reporter Glyco-DTE (1 × 10−5 mol/L in PBS buffer, 0.25‰ Triton X-100) upon addition

Morphology-tunable and pH-responsive supramolecular self-assemblies based on AB₂-type host–guest-conjugated amphiphilic molecules for controlled drug delivery

• Yang Bai,
• Cai-ping Liu,
• Di Chen,
• Long-hai Zhuo,
• Huai-tian Bu and
• Wei Tian

Beilstein J. Org. Chem. 2019, 15, 1925–1932, doi:10.3762/bjoc.15.188

• -assembly and the size of β-CD-BM2-based supramolecular self-assemblies under neutral and acidic pH were first investigated by employing transmission electron microscopy (TEM) and dynamic light scattering (DLS). The prepared β-CD-BM2 were dissolved under neutral pH solution to form FSSAs. TEM revealed that

• proliferation was high. All these results indicate that these supramolecular self-assemblies might have a potential application in the field of controlled release. Typical TEM images (a–d) and DLS curves (e) of β-CD-BM2-based supramolecular self-assemblies at pH 7.4 (a, c, e) and pH 5.0 (b, d, e), respectively

A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• subjected to various studies like SEM, TEM and DLS experiments. The DLS data revealed that the dispersed particles size in the aqueous phase varied from ≈60 nm to ≈105 nm (Figure 2a). Interestingly, when the same dispersion was used for the analysis of the particle size distribution on a solid surface, i.e

• ., in SEM and TEM, the diameters were also found to be in the range of 70–100 nm (Figure 2b and 2c). So, these studies supported the nanoranged dispersion of the macrocycle, which indeed follows the basic characteristic of a nanoreactor. Optimization of the reaction conditions for the synthesis of

• . Therefore, BATA-MC has the prospective of reworking at least five times. SEM and TEM images of the catalyst’s nanoranged dispersive particles after five cycles are given in Supporting Information File 1 (Figure S4) which confirm the range of particle sizes of 70–110 nm even after five cycles. Conclusion In

Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

• Maximilian Niehues,
• Patricia Tegeder and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2019, 15, 1407–1415, doi:10.3762/bjoc.15.140

• nanoparticle systems [46]. This interpretation is also supported by TEM images (Figure 4a, see below) indicating significant interparticle repulsion and no aggregation-induced absorption maxima broadening. For further experiments the [tCD+tTEG]AuNR stock solution was diluted with ddH2O. For the photoresponsive

• -dependent nanoparticle settling and is in agreement with other studies on linear assemblies of AuNR [12]. To visualize the AuNR end-to-end assemblies, TEM measurements have been conducted (Figure 4b and c, see below) showing chains of AuNR. Hardly any unselective side-by-side or random assemblies can be

• observed which are often seen in various publications and are due to unspecific drying effects during the TEM grid preparation [11][27]. Adding the dAAP to the intermediate state of the ligand exchange ([tCD]AuNR, with CTAB surface coating on the sides of the particles) showed no significant shift of the

N-doped carbon dots covalently functionalized with pillar[5]arenes for Fe³⁺ sensing

• Jia Gao,
• Ming-Xue Wu,
• Dihua Dai,
• Zhi Cai,
• Yue Wang,
• Wenhui Fang,
• Yan Wang and
• Ying-Wei Yang

Beilstein J. Org. Chem. 2019, 15, 1262–1267, doi:10.3762/bjoc.15.123

• microscopy (TEM) (Figure 1a). TEM images showed the spherical shape of CCDs with a diameter of 9 nm. For comparison, the shape of CN-dots was quasi-spherical with an average diameter of 7 nm (Figure 1b). As shown in Figure 1c, the UV–vis absorption peak of CN-dots is at 340 nm, and CP[5] has an obvious UV

• Fe3+ ions with high selectivity. TEM images of a) CCDs and b) CN-dots. c) UV–vis spectra of CP5, CN-dots, and CCDs. d) FTIR spectra of CP5, CN-dots, and CCDs. e) PXRD patterns of CP5, CN-dots, and CCDs. f) TGA curves of CN-dots and CCDs. a) Photographs of CN-dots and CCDs in aqueous media in natural

Self-assembly behaviors of perylene- and naphthalene-crown macrocycle conjugates in aqueous medium

• Xin Shen,
• Bo Li,
• Tiezheng Pan,
• Jianfeng Wu,
• Yangxin Wang,
• Jie Shang,
• Yan Ge,
• Lin Jin and
• Zhenhui Qi

Beilstein J. Org. Chem. 2019, 15, 1203–1209, doi:10.3762/bjoc.15.117

•  1d). In the polar solvents MeCN and MeOH, fluorescence of 2 becomes much weaker, and is almost totally quenched in H2O. In order to observe the aggregates formed by 1 and 2 visually in solutions, transmission electron microscopy (TEM) was utilized. First, the aggregates of 1 formed in CHCl3 and MeCN

• the weaker π–π stacking of 2 leading to a less regular packing arrangement, no regular morphology was observed when CHCl3 or MeCN was used as solvent (Figure 2d and 2e), and only a short nanobelt was observed in H2O/MeCN (v/v = 10:1, Figure 2f). The TEM characterization result was corroborated well by

• their UV–vis absorption and fluorescence properties. An unexpected fluorescence quenching phenomenon was observed in the PDI-B21C7 macrocycle conjugate in chloroform. Through TEM characterization, it was illustrated that in aqueous medium, both PDI and NDI derivatives containing crown ether units could

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• % (Scheme 22) [44]. Polymers with a weight-average molecular mass in the range from 67000 to 88000 Da were obtained. In the random copolymers obtained, the associative interactions between the particles were shown to result in the formation of ordered nanostructures. TEM micrographs indicate that the

• the range of 1.3–1.9. The surface morphology and thermal properties of hybrids were found to be affected by the POSS macromer. TEM analysis of copolymer films revealed the presence of POSS agglomerates. An analogous macromer bearing POSS-bound via phenylene linker was used in the synthesis of a series

• of polymers and copolymers with 3-(trifluoromethyl)phenyl-7-oxanorbornene-5,6-dicarboximide (Scheme 25) [48]. It was found that the increase in the content of POSS units in the copolymer results in a decrease in thermal stability and Tg values. TEM and AFM microimages show spherical POSS aggregates

Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• regarded as a non-piliated genus; however, recently, studies using transmission electron microscopy (TEM) and atomic force microscopy (AFP) have identified long appendages on the surfaces of M. smegmatis and Mtb, which could be identified as pili [108][109][110]. Two different pili types were detected for

An overview on recent advances in the synthesis of sulfonated organic materials, sulfonated silica materials, and sulfonated carbon materials and their catalytic applications in chemical processes

• Hashem Sharghi,
• Pezhman Shiri and
• Mahdi Aberi

Beilstein J. Org. Chem. 2018, 14, 2745–2770, doi:10.3762/bjoc.14.253

• 2900 cm−1 and 3400 cm−1 were the evidence of phenylic C–H bond and N–H stretching of carbazole, respectively. Peaks at 1022 cm−1 and 1039 cm−1 corresponded to additional crosslinking during the sulfonation process. The catalyst was investigated by BET, SEM, TEM, and TGA-DTA, as well. The BET surface

Bioinspired cobalt cubanes with tunable redox potentials for photocatalytic water oxidation and CO₂ reduction

• Zhishan Luo,
• Yidong Hou,
• Jinshui Zhang,
• Sibo Wang and
• Xinchen Wang

Beilstein J. Org. Chem. 2018, 14, 2331–2339, doi:10.3762/bjoc.14.208

• spectrometer with KBr as the diluents. Electrochemical measurements were conducted with a Biologic VSP-300 Electrochemical System in a conventional three electrode cell. The 1H NMR experiments were performed on Bruker AVANCE 400M spectrometers. Transmission electron microscopy (TEM) was obtained using a FEI

Functionalization of graphene: does the organic chemistry matter?

• Artur Kasprzak,
• Agnieszka Zuchowska and
• Magdalena Poplawska

Beilstein J. Org. Chem. 2018, 14, 2018–2026, doi:10.3762/bjoc.14.177

• for functionalized GO: 1639 cm−1). This unexpected statement was supported, not by further spectroscopic analyses, but by morphological studies (transmission electron microscopy (TEM) and atomic force microscopy (AFM)) only. Once again, the possible electrostatic adsorption or hydrogen bonding

Graphitic carbon nitride prepared from urea as a photocatalyst for visible-light carbon dioxide reduction with the aid of a mononuclear ruthenium(II) complex

• Kazuhiko Maeda,
• Daehyeon An,
• Ryo Kuriki,
• Daling Lu and
• Osamu Ishitani

Beilstein J. Org. Chem. 2018, 14, 1806–1812, doi:10.3762/bjoc.14.153

• content was obviously lower. The hydrogen and oxygen impurities were also reduced with an increase in the synthesis temperature. These results indicate that rising temperature is important to obtain purer g-C3N4 in terms of the chemical composition. TEM images of the same samples are shown in Figure 3

• in this study. Ag nanoparticles loaded on mpg-C3N4 serves as a promoter of electron transfer from mpg-C3N4 to RuP, as discussed in our previous work [13]. TEM observation indicated that the loaded Ag is in the form of nanoparticles of 5–10 nm in size (Figure 5). Without Ag (i.e., RuP/g-C3N4), formate

• Kα radiation), Fourier-transform infrared (FTIR) spectroscopy (FTIR-610, Jasco), transmission electron microscopy (TEM) (JEM-2010F, JEOL), and UV–visible diffuse reflectance spectroscopy (DRS) (V-565, Jasco). The Brunauer–Emmett–Teller (BET) surface area of each specimen was determined using a

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

• Cristina Morar,
• Pedro Lameiras,
• Attila Bende,
• Gabriel Katona,
• Emese Gál and
• Mircea Darabantu

Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145

• macromolecular shape in solution). DFT calculations (in solution), (VT) NMR and IR (KBr) spectroscopy supported these assignments. TEM analysis revealed the ability of the title compounds towards self-assembling into homogeneously packed spherical nano-aggregates. Conclusions: The (non)covalent synthesis and

• quantitative yields (Scheme 4) (Supporting Information File 1, pp. S6–S11; pp. S24–S39, Figures S25–S54). 3 Structural assignments Our research continued with a structural study, implemented by means of DFT calculations, solution (VT) NMR techniques, IR (KBr) spectroscopy and TEM analysis. 3.1 Assignments

• -hydroxyphenyl-based amino-s-triazine analogues of 2a and 3 [35][36], the optimised (a–a) geometry was found to be largely dominant, both in the gas phase as well as in solution, e.g., DMSO, which was the most appropriate solvent for (VT) 1H NMR and TEM investigations (see section 3.2). As expected, the relative

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• a polymer electrolyte membrane electrochemical reactor (PEMER). Palladium (Pd) nanoparticles were synthesised and supported on a carbonaceous matrix (Pd/C) with a 28 wt % of Pd with respect to carbon material. Pd/C was characterised by transmission electron microscopy (TEM), and thermogravimetric

• water-in-oil (w/o) microemulsion (water/Brij@30/n-heptane). This methodology has been previously used in our laboratory [27][28]. We first explored the morphology, size and dispersion of Pd nanoparticles supported on Vulcan XC72R carbonaceous material (Pd/C electrocatalysts) using TEM micrographs. As

• is the Toray paper support. Morphology, size and dispersion of Pd nanoparticles in Pd/C were analysed by a transmission electron microscopy (TEM) using a JEOL JEM-2012 instrument with an accelerating voltage of 300 kV. The TEM was connected with an energy dispersion X-ray (EDX) for the analysis of

Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles

• Vivek Poonthiyil,
• Thisbe K. Lindhorst,
• Vladimir B. Golovko and
• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 11–24, doi:10.3762/bjoc.14.2

• -AuNPs and ATT-AuNPs (Figure S3) are also provided in Supporting Information File 1. Whenever water-soluble ligands are used to perform exchange reactions on Cit-AuNPs, the wine-red colour of the AuNP solution (which corresponds to the dispersed state of the AuNPs as can be confirmed by TEM), and the SPR

• File 1, Figure S5). Furthermore TEM revealed partial aggregation of the particles (Supporting Information File 1, Figure S6). However, despite this partial aggregation the ATT-AuNP solution was stable without any precipitation at least for three months when stored at 4 °C. Similar observations have

• 88: Synthetic protocols and spectral and TEM characterisation for ATT 33 (Scheme 11), ATT-AuNPs (Scheme 11), GlcNAc azide 34, and click reaction of ATT-AuNPs.

Synthesis and supramolecular properties of regioisomers of mononaphthylallyl derivatives of γ-cyclodextrin

• Markéta Bláhová,
• Sergey K. Filippov,
• Lubomír Kováčik,
• Jiří Horský,
• Simona Hybelbauerová,
• Zdenka Syrová,
• Tomáš Křížek and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2017, 13, 2509–2520, doi:10.3762/bjoc.13.248

• -(naphthalen-2-yl)allyl chloride as the alkylating reagent. Highly regioselective reaction conditions, which differ for each regioisomer in a used base, gave the monosubstituted isomers in yields between 12–19%. Supramolecular properties of these derivatives were studied by DLS, ITC, NMR, and Cryo-TEM

• light scattering (DLS) [18][19][20][21] and cryo-transmission electron microscopy (Cryo-TEM) [22][23][24]. Results and Discussion Synthesis We present two approaches for the synthesis of naphthylallyl (NA) derivatives. The first approach is a cross-metathesis of peracetylated allyl derivatives of γ-CD

• nm and 300 nm. The 2-O-sample did not show any temperature dependence. Transmission cryo-electron microscopy (Cryo-TEM) The supramolecular properties of the individual regioisomers (2-O-, 3-O-, 6-O-) of NA-γ-CD 2a–c and the dependence of the formation of the self-assembled structures on their

New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

• Daily Rodríguez-Padrón,
• Alina M. Balu,
• Antonio A. Romero and
• Rafael Luque

Beilstein J. Org. Chem. 2017, 13, 1982–1993, doi:10.3762/bjoc.13.194

• electron microscopy (TEM). The micrographs show a homogeneous distribution of iron oxide nanoparticles for the three catalysts (Figure 3A,C,E). The analysis of the SEM images reveals the tendency of the constituent particles of the magnetic material to form agglomerates due to their nanometer size (Figure

• 300 °C under air and kept at that temperature for 30 min. Material characterization In order to characterize the synthesized materials, several techniques have been employed, including XRD, XPS, absorption–desorption of N2, SEM, TEM, DRIFT and titrations with pyridine and dimethylpyridine. In addition

• obtained from the N2 desorption branch. Electron microscopy SEM images and the elemental composition were recorder using the JEOL JSM-6490 LV microscope. The samples were Au/Pd-coated on a high-resolution sputter SC7640 at a sputtering rate of 1.5 kV per minute, up to 7 nm thickness. TEM micrographs were

Ni nanoparticles on RGO as reusable heterogeneous catalyst: effect of Ni particle size and intermediate composite structures in C–S cross-coupling reaction

• Debasish Sengupta,
• Koushik Bhowmik,
• Goutam De and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 1796–1806, doi:10.3762/bjoc.13.174

• materials were well characterized by powder XRD, TEM, TGA and XPS studies. The preparation and characterization of the nanocomposites were described in detail in our previous publications [48][49]. Usually, bare Ni NPs are unstable and likely to undergo aerial oxidation [43]. However, in the Ni/RGO

• TEM studies. The Raman and XRD results of fresh Ni/RGO-40 were reported in our previous publication [48]. However, for comparison, Raman and XRD of a fresh Ni/RGO-40 sample were again recorded and presented along with that of the recovered sample. The Raman spectrum of the Ni/RGO-40 composite (Figure

• first run (Figure 3b and Figure 4b). In support of our proposed reaction mechanism, we analyzed the TEM images of the fresh Ni/RGO-40 catalyst and the recovered one after the first cycle of catalysis. In Figure 7a, we show the TEM image of fresh Ni/RGO-40 (figure reproduced from our earlier publication

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• from the same H2PdCl4 and PVP aqueous solution using MW irradiation (see Supporting Information File 1). The morphology and size of the Pd NPs was determined by TEM micrographs. Unfortunately, these MW-synthesized NPs proved to be inactive as catalysts in the Mizoroki–Heck coupling reaction between 1a

• cycles of the Heck–Mizoroki coupling reaction. The initial drop could be explained by taking into account that the product and substrates are not soluble in the aqueous media causing a non-homogeneous heating and stirring of the system [63]. TEM micrograph of PVP-Pd NPs before and after one catalytic

• cycle was performed. The physical separation of NPs was carried out by centrifugation as previously reported [48]. The comparison of both TEM micrographs disclosed that the original PVP-Pd NPs [(9 ± 2) nm] clump to larger aggregates after the first catalytic cycle, providing NPs with a mean diameter of