Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• at around 345 °C for both the βNS-CDI 1:4 from DMF and for the βNS-CDI 1:4 from ball mill. The initial mass loss present in both βNS-CDI 1:4 was due to adsorbed environmental water, always present when dealing with hygroscopic cyclodextrin-based nanoparticles. In addition to this, the particle size

• nucleophilic carboxylic group. The simplified schematic reaction (previously reported by Staab [31] and more recently by Jadhav et al. [33]), with the relative ζ-pot of nanoparticles after functionalization, is presented in Figure 8. Through a simple reaction in closed vials with an excess (dye/CD ratio) of

• carbonate NS synthesized in a solvent and displayed insolubility in water and organic solvents. FTIR and TG analyses were performed on the new material, confirming the structure with a carbonate bond. Nanoparticles, after cycles of ball milling and high-pressure homogenization had a mean diameter of less

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

• nanoparticles) or by introducing impurities into the crystal lattice, otherwise known as doping [44][84][85][86]. Semiconductor doping adds additional filled or vacant quantum states to the band structure that lie within the band gap, reducing the Eg and typically resulting in a bathochromic shift in absorption

• solubility of the photocatalyst being poor in those solvents [139]. 2.4 Solid-supported semiconductors and metal nanoparticles For the same reasons outlined in the previous section, the immobilisation of thin films of semiconductors and the deposition of metal nanoparticle photocatalysts can improve the

• treatment [146]. Dip-coating has also been commonly applied to coat other inorganic substrates, such as glass spheres, carbon nanotubes, and diatomite with TiO2 thin films for photocatalysis applications [147][148][149][150]. Scaiano and co-workers deposited platinum nanoparticles on TiO2(P25) powder as a

Cation-induced ring-opening and oxidation reaction of photoreluctant spirooxazine–quinolizinium conjugates

• Phil M. Pithan,
• Sören Steup and
• Heiko Ihmels

Beilstein J. Org. Chem. 2020, 16, 904–916, doi:10.3762/bjoc.16.82

• silver(I) or gold(III) ions, the spironaphthoxazine 1aSO or the corresponding 5-chloro-substituted analog underwent thermal–oxidative degradation even under an inert gas atmosphere in the dark [74][75]. Based on the formation of silver or gold nanoparticles during the reaction, the authors proposed a two

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

• /mechanical stability, and good adsorption capacity. They also contain an ordered porous network that is appropriate for the free diffusion of reactants and reaction products [24]. In this regard, various functionalized SiO2 nanoparticles were employed in diverse organic reactions, including Suzuki–Miyaura

• reactions, Ugi–Smiles reactions, Mizoroki–Heck reactions, aldol reactions, oxidation and dehydration reactions, Mannich reactions, and multicomponent reactions. Because of the mentioned reasons as well as due to the low toxicity of silica nanoparticles, they are often a good option [24]. For this review

• article, we have provided an overview on the synthesis and functionalization of SiO2 nanoparticles and on the investigation on their catalytic applications in CuAAC reactions. Rhee et al. immobilized Cu(I) and Cu(II) species onto reverse-phased silica gel [25]. In this work, a 2-pyridinecarboxaldehyde

Photophysics and photochemistry of NIR absorbers derived from cyanines: key to new technologies based on chemistry 4.0

• Bernd Strehmel,
• Christian Schmitz,
• Ceren Kütahya,
• Yulian Pang,
• Anke Drewitz and
• Heinz Mustroph

Beilstein J. Org. Chem. 2020, 16, 415–444, doi:10.3762/bjoc.16.40

• electrochemically mediated ATRP (eATRP) [122][123][124][125][126][127][128]. In this content, various reducing agents, and electrochemical redox processes, and copper comprising nanoparticles have been accomplished to conduct ATRP by generating the required Cu(I) by the reduction of Cu(II) complexes. A well written

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

• . Results and Discussion Synthesis and characterisation of the Ru nanocatalyst The surfactant- and stabiliser-free RuNC was synthesised photochemically, based on a procedure that we have previously reported for the synthesis of Pd nanoparticles [46][47]. The synthesised RuNC, obtained directly after

• 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

• considerable agglomeration of the individual nanoparticles (Figure S4, Supporting Information File 1). The HRTEM–SAED diffraction image showed the presence of several crystalline phases, including those for Ru(0) and RuO2 (Figure S5, Supporting Information File 1). More specifically, the crystalline planes

One-pot synthesis of substituted pyrrolo[3,4-b]pyridine-4,5-diones based on the reaction of N-(1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-oxo-2-arylethyl)acetamide with amines

• Valeriya G. Melekhina,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Vitaly S. Mityanov,
• Artem N. Fakhrutdinov,
• Arkady A. Dudinov,
• Vasily A. Migulin,
• Yulia V. Nelyubina,
• Elizaveta K. Melnikova and
• Michail M. Krayushkin

Beilstein J. Org. Chem. 2019, 15, 2840–2846, doi:10.3762/bjoc.15.277

• -one (4), arylglyoxals 5, and acetamide (6) using SnCl2–SiO2 nanoparticles as heterogeneous catalyst under solvent-free conditions [10]. However, as we found out, the use of a catalyst was unnecessary for this transformation. In turn, refluxing the reaction mixture in acetonitrile was sufficient for

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• induced by addition of certain concentration of alkaloid which was found to get adsorbed on CuNP surface (Scheme 12). In continuation, Wang and Lu, in 2016, developed a ‘copper encapsulated alkaloid composite’ by the entrapment of commercial alkaloids within metallic copper nanoparticles. They compacted

• -induced asymmetric electrochemical hydrogenation of 2,2,2-trifluoroacetophenone 32 nanoparticles was also developed (Scheme 13). These NPs with low Pt loading were further obtained by reducing platinum precursors on Cu NPs [41]. Yadav’s group, in 2013, described preparative scale enantioselective cathodic

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

• , France 10.3762/bjoc.15.260 Abstract Upconverting nanoparticles are a rising class of non-linear luminescent probes burgeoning since the beginning of the 2000’s, especially for their attractiveness in theranostics. However, the precise quantification of the light delivered remains a hot problem in order

• green emission of NaYF4:Yb,Er nanoparticles. Using the recently calibrated actinometer 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene operating in the green region of the visible spectra, we propose a simple photochemical experiment to get an accurate estimation of the

• , typically near infrared (NIR), into high energy one thanks to noncoherent photon absorption is called “upconversion”. This phenomenon is exemplified by the lanthanide-based materials [1]. With the rapid developments of nanotechnology, upconverting Ln3+-based nanoparticles (UCNPs) have been reported for

Reversible switching of arylazopyrazole within a metal–organic cage

• Anton I. Hanopolskyi,
• Soumen De,
• Michał J. Białek,
• Yael Diskin-Posner,
• Liat Avram,
• Moran Feller and
• Rafal Klajn

Beilstein J. Org. Chem. 2019, 15, 2398–2407, doi:10.3762/bjoc.15.232

• interfaces [1][2][3], in self-assembled cages [4][5][6][7], on DNA chains [8], and on the surfaces of inorganic nanoparticles [9][10]. Additionally, nanosized cages can induce preorganization of the encapsulated species, thus inducing unusual regioselectivities in various chemical reactions [11][12][13]. The

• ] and, using larger cages, the synthesis of 4 nm silica nanoparticles, which would be difficult to obtain otherwise [15]. One class of organic compounds that exhibit various intriguing properties under confinement is photochromic molecules. In a seminal contribution, unusual switching patterns have been

• affected by their confinement to the surfaces of inorganic nanoparticles. Among other examples, the isomerization kinetics of azobenzene could be tuned by a factor of >5000 by the molecules with which it was co-adsorbed on gold nanoparticles [23], and donor–acceptor Stenhouse adduct (DASA) switches were

Host–guest interactions in nor-seco-cucurbit[10]uril: novel guest-dependent molecular recognition and stereoisomerism

• Xiaodong Zhang,
• Wei Wu,
• Zhu Tao and
• Xin-Long Ni

Beilstein J. Org. Chem. 2019, 15, 1705–1711, doi:10.3762/bjoc.15.166

• adamantaneammonium (ADA) or alkylammonium ions into the cavity, forming a ternary complex. The novel binding capacity of NS-CB[10] has been utilized to form supramolecular polymers [24][25][26] and polymer nanoparticles [27]. More importantly, Isaacs et al. discovered that when the unsymmetrical guest ADA molecules

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

• ][42][43][44]. Various copper salts have been used as Lewis acid in homogeneous catalysis. CuO nanoparticles (NPs) were used for C–N, C–S, C–O cross-coupling reactions and C-arylation. Recently, exploiting the cross-coupling tendency of CuO NPs, Reddy et al. have reported their use as a heterogeneous

• organic reactions. In the syntheses of IPs, various forms of copper viz., salts, complexes, MOFs, oxides, and nanoparticles (NPs) have been used as the catalytic system in both multicomponent reactions (MCRs) as well as derivatization methodologies. The role of palladium in synthetic chemistry Pd

Synthesis, enantioseparation and photophysical properties of planar-chiral pillar[5]arene derivatives bearing fluorophore fragments

• Guojuan Li,
• Chunying Fan,
• Guo Cheng,
• Wanhua Wu and
• Cheng Yang

Beilstein J. Org. Chem. 2019, 15, 1601–1611, doi:10.3762/bjoc.15.164

• further investigated by dynamic light scattering (DLS) analyses, and revealed the formation of nanoparticles with 615 nm in average diameter after the addition of 50% water (Figure 4d). Increasing the amount of water to 70% or 90% led to a bathochromic shift of the UV–vis absorption and a raise of the

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

• cycles. By the introduction of AAP, previous disassembly limitations based on the photostationary states of azobenzenes could be solved. The combination photoresponsive interaction and selectively end-functionalized nanoparticles shows significant potential in the reversible self-assembly of inorganic

• sensing properties [4][5]. In particular, noble metal nanoparticles of sizes smaller than the wavelength of the incident light show interesting optical behavior as a result of collective oscillations of the valence electrons. This leads to surface plasmon resonance (SPR), which is highly dependent on size

• a longitudinal SPR (LSPR) band that can reach up to the near infrared (NIR) region [9]. The LSPR band can be tuned over a wider wavelength range than for isotropic nanoparticles by varying the aspect ratio of the AuNR or by the assembly of multiple AuNR into linear clusters [10]. These linear

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• DTT 1 in 91% yield (Scheme 1). Triacene dithieno[3,2-b:2’,3’-d]selenophene (DTS, 2) was successfully prepared as well from diiodinated bithiophene 5 in 51% yield after purification in a C–Se cross-coupling/cyclization reaction with selenourea as selenium source, copper oxide nanoparticles as catalyst

• corresponding dibromobiselenophene and benzene sulfonyl sulfide as sulfur source (50% yield) [27]. In parallel, TMS-protected iodinated biselenophene 11 was subjected to selenourea, copper oxide nanoparticles, and potassium hydroxide in DMSO to isolate diselenolo[3,2-b:2’,3’-d]selenophene (DSS, 4) in 48% yield

• deprotection with TBAF in 66% yield, with selenourea and copper oxide nanoparticles surprisingly did not lead to any targeted DSS 4 in the attempted C–Se cross-coupling reaction. The structures of the prepared novel selenolotriacenes 2–4 and known DTT 1 were characterized by means of NMR spectroscopy

Diaminoterephthalate–α-lipoic acid conjugates with fluorinated residues

• Leon Buschbeck,
• Aleksandra Markovic,
• Gunther Wittstock and
• Jens Christoffers

Beilstein J. Org. Chem. 2019, 15, 981–991, doi:10.3762/bjoc.15.96

• sensorics [19], microcontact printing [20], dip-pen nanolithography [21], microfluidics [22], and protection of nanoparticles [23]. Initially, surface modification aimed on controlling physical properties of surfaces [24][25], while nowadays chemical surface properties can be tuned to yield platforms for

Easy, efficient and versatile one-pot synthesis of Janus-type-substituted fullerenols

• Marius Kunkel and
• Sebastian Polarz

Beilstein J. Org. Chem. 2019, 15, 901–905, doi:10.3762/bjoc.15.87

• in one person or object. Consequently, nanoparticles characterized by two different hemispheres have been named Janus-type nanoparticles as well, and have attracted major attention due to their special properties [1][2]. The term 'Janus' is much less used in molecular chemistry, presumably because

Synthesis of 2H-furo[2,3-c]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction

• Vaida Milišiūnaitė,
• Rūta Paulavičiūtė,
• Eglė Arbačiauskienė,
• Vytas Martynaitis,
• Wolfgang Holzer and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2019, 15, 679–684, doi:10.3762/bjoc.15.62

• fluorescent organic nanoparticles [31][32][33][34]. The iodination of 1 with iodine in the presence of KOH in DMF afforded 4-iodo-1H-pyrazol-3-ol 2 [26]. We have previously shown that the Sonogashira-type coupling of the aforementioned iodinated compound with phenylacetylene under standard reaction conditions

Polyaminoazide mixtures for the synthesis of pH-responsive calixarene nanosponges

• Antonella Di Vincenzo,
• Antonio Palumbo Piccionello,
• Alberto Spinella,
• Delia Chillura Martino,
• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2019, 15, 633–641, doi:10.3762/bjoc.15.59

• area of the nanosponge–metal nanoparticles conjugates. Experimental Materials. All the reagents and solvents needed were used as purchased (Aldrich, Fluka) without further purification. The calixarene derivative Ca [39] and the non-commercial nitroaniline derivatives 7–10 [31][33] were prepared

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

• -dihydropyridine derivatives may be also accomplished by using catalysis with organometallic complexes [72][73][74][75][76][77][78][79] or platinum nanoparticles [80]. This recently developed approach stems from an independent field of research, which focuses on the regeneration of NAD(P)H from NAD(P)+ [81][82

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

• copolymerization of norbornenylethyl-POSS with methyltetracyclododecene in the presence of first generation Grubbs catalyst (Ru-1) is a practical route to the synthesis of block copolymers containing POSS nanoparticles (Scheme 26) [50]. ROMP of norbornenylethyl-POSS produced the corresponding homopolymer in

Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• , IBI, and SIBIS multiblock copolymers, which include glassy, rubbery, and semicrystalline polymer segments and demonstrate peculiar mechanical behavior [57][58]. References [59] and [60] report on the preparation of fluorescent polymer nanoparticles for bioimaging and in vivo targeting of tumors and

• the nanoparticles were formed by a ABCBA pentablock copolymer. In this polymer A stands for hydrophilic oligo(ethylene glycol) (OEG)-grafted polynorbornene possessing stealth-like and antifouling properties that are useful for in vivo applications. The B block is formed by polynorbornene

• obtain the ABCBA pentablock copolymers. This copolymer forms nanoparticles with a central hydrophobic core capable of accommodating fluorescent dyes and conventional therapeutics and a hydrophilic biocompatible outer shell. The efficient combination of the ROMP process and click chemistry led to the

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

• fields including adsorbent, optical devices, water purification, drug delivery, and catalysis. Silica nanoparticles with different structures have extensively investigated due to their simple preparation and diverse industrial applications. In addition, SiO2 nanoparticles with high surface area commonly

• 80 °C using MWCNTs-SO3H composite 97 as the efficient and heterogeneous catalyst. The reaction was also performed under the same conditions using different catalysts including Fe3O4, CuFe2O4, ZnS nanoparticles, TiO2, MWCNTs, MWCNTs/H2SO4, MWCNTs–COOH, and Ph–SO3H, but the products were not achieved

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

• nanoparticles in the reaction mixture (Supporting Information File 1, Figure S7). These results also support the above discussion. The presence of 1-R with an enhanced electron-withdrawing ability can significantly reduce the overpotential for the O–O bond formation, and thus facilitates water oxidation

Bi-mediated allylation of aldehydes in [bmim][Br]: a mechanistic investigation

• Mrunesh Koli,
• Sucheta Chatterjee,
• Subrata Chattopadhyay and
• Dibakar Goswami

Beilstein J. Org. Chem. 2018, 14, 2198–2203, doi:10.3762/bjoc.14.193

• aqueous KF [31] or aqueous HBr [34] as the metal activator. As an alternative, Xu et al. found nano-Bi to be more effective than regular Bi-powder, although this method had an intrinsic difficulty of preparing Bi-nanoparticles via reduction of Bi(III) salts [35]. These apart, combinations of Bi(III) salts