Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• absorption at 1120 nm. Nonetheless, the spectra of the dications 12+ and 22+ display noticeably differences given that the features at 421 and at 1007 nm, present in the angular [3]naphthylene 2, are apparently absent in the linear isomer 1. Raman spectroscopy Figure 4 shows the experimental Raman spectrum

• 15 mV. Raman spectroscopy Raman spectra were obtained using a Bruker® RAMII Fourier transform Raman spectrometer, purged with dry nitrogen. Excitation radiation at 1064 nm was generated by a Nd-YAG laser working at 500 mW. Backscattering collection of the Raman radiation was performed. Typically

Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

• overlapping peaks. Its versatility was showcased through the successful completion of four comprehensive case studies, demonstrating its broad applicability across diverse analytical scenarios. Recently, we implemented in-line Raman spectroscopy to monitor the real-time conversion of styrene to polystyrene

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• in a much shorter time (Table 1, entry 4) when the temperature of the reaction medium was increased to 50 °C. According to X-ray and Raman spectroscopy techniques, triglyceride molecules in liquid form are arranged in a dynamic chain-like conformation [114][115][116]. As the temperature of the

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• -TOF mass spectra. Upon extraction of SWNTs with the nanobracket and copper(II), in situ-formed square Cu-nanobrackets are found to interlock SWNTs to disperse them in 2-propanol. The interlocking is confirmed by Raman spectroscopy after thorough washing of the extracted SWNTs. Pristine SWNTs were

• moieties absorbing ≈465 nm light (Figure 1b) should be excited at the resonance Raman spectroscopy using a 488 nm laser. This is supported by the observation that the excitation at 633 and 785 nm where 1b did not show any absorption (Figure 1b) did not give any Raman signals [20]. Extraction of SWNTs with

• in Figure 3b, all the materials were analyzed with Raman spectroscopy in the solid phase with normalization at G-band (1570 cm−1) of SWNTs. The characteristic signals from Cu-nanobrackets 1b are observed in e- and i-SWNTs, but not in p-SWNTs, indicating the interlocking of SWNTs with 1b, because the

Spin and charge interactions between nanographene host and ferrocene

• Akira Suzuki,
• Yuya Miyake,
• Ryoga Shibata and
• Kazuyuki Takai

Beilstein J. Org. Chem. 2024, 20, 1011–1019, doi:10.3762/bjoc.20.89

• photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, magnetic susceptibility, and electron-spin resonance (ESR). Experimental Commercially available ACFs (Kuraray, FR-20), of which the precursor was a phenol-resin, were pre-heat-treated in a glass tube at 200 °C

• surface of ACFs, which were removed by heating the FeCp2-treated ACFs at 150 °C for 3 hours without FeCp2 vapor. XPS spectra were recorded using a PHI-5600 (ULVAC-PHI) with an Al Kα X-ray source (1486.7 eV) for samples mounted on an indium film. Raman spectroscopy measurements were performed by LabRAM HR

Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• performed in situ reaction monitoring of the milling process by Raman spectroscopy [32][33]. In an experiment milling 1c with NFSI (1 equiv) we observed the consumption of NFSI after ca. 30 min of milling as evidenced by a reduction in the intensity of the band at 1197 cm−1 of NFSI (Figure S3 in Supporting

• of solvent. Being a crystalline material [43] and a Raman and IR active molecule [44][45], NFSI enabled the monitoring of the reactions by ex situ PXRD and IR spectroscopy, as well as by in situ Raman spectroscopy. Such a monitoring enabled us to understand background reactions such as the

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

An initiator- and catalyst-free hydrogel coating process for 3D printed medical-grade poly(ε-caprolactone)

• Jochen Löblein,
• Thomas Lorson,
• Miriam Komma,
• Tobias Kielholz,
• Maike Windbergs,
• Paul D. Dalton and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2021, 17, 2095–2101, doi:10.3762/bjoc.17.136

• photopolymerization for the hydrophilic modification of microfiber scaffolds obtained from hydrophobic medical-grade poly(ε-caprolactone) via melt-electrowriting. Contact angle measurements and Raman spectroscopy confirms the formation of a more hydrophilic coating of poly(2-hydroxyethyl methacrylate). Apart from

UV resonance Raman spectroscopy of the supramolecular ligand guanidiniocarbonyl indole (GCI) with 244 nm laser excitation

• Tim Holtum,
• Vikas Kumar,
• Daniel Sebena,
• Jens Voskuhl and
• Sebastian Schlücker

Beilstein J. Org. Chem. 2020, 16, 2911–2919, doi:10.3762/bjoc.16.240

• the results from density functional theory (DFT) calculations. Keywords: GCI; GCP; guanidiniocarbonyl indole; guanidiniocarbonyl pyrrole; UVRR; Raman spectroscopy; resonance Raman; Introduction Supramolecular ligands are capable to selectively bind to peptides and proteins via reversible non

• probe the entire chromophore and are sensitive only to changes in the electronic structure of the molecule. In contrast, vibrational spectroscopic techniques such as infrared (IR) and Raman spectroscopy provide a much more detailed picture at the level of chemical bonds since they probe the intrinsic

• of the small number of vibrational peaks. Additionally, IR spectroscopy suffers from the strong absorption by water. In contrast, this is not a problem in Raman spectroscopy because water is a weak Raman scatterer. Conventional Raman spectroscopy under nonresonant conditions is typically limited to

Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

• Si-Yuan Liu,
• Xin-Rui Wang,
• Man-Ping Li,
• Wen-Rong Xu and
• Dietmar Kuck

Beilstein J. Org. Chem. 2020, 16, 2551–2561, doi:10.3762/bjoc.16.207

• Ka = (2.20 ± 0.16) × 105 M−1, respectively. The binding affinity between TBTQ-(OG)6 and C60 was further verified by Raman spectroscopy. The geometry of the complex of TBTQ-(OG)6 with C60 deduced from DFT calculations indicates that the driving force of the complexation is mainly due to the

• equivalents of TBTQ-(OG)6, while the maximum solubility of C70 was about 0.17 mg/mL. Raman spectroscopy has proven to be a useful tool for the characterization of carbon nanomaterials [51][52]. The Raman spectra of TBTQ-(OG)6, C60 and TBTQ-(OG)6 C60 are displayed in Figure 5. The TBTQ-(OG)6 shows a weak peak

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• pyridines via C–N, C–C, and C–S bond formations in a mixture of ethanol and H2O under ultrasound irradiation. The catalyst is characterized by XRD, FTIR, Raman spectroscopy, SEM, and EDAX analysis. The main advantages of this methodology include the wide substrate scope, cleaner reaction profile, short

• presence of aluminium silicates and iron oxides present in the sample were confirmed by Raman spectroscopy. The bands at 418, 578, 753, and 985 cm−1 were assigned to Al–O bending, Si–O rocking, Al–O stretching, and Si–OH stretching vibrations, respectively [85]. Further, a very weak peak at 618 cm−1 was

Mechanochemical Friedel–Crafts acylations

• Mateja Đud,
• Anamarija Briš,
• Iva Jušinski,
• Davor Gracin and
• Davor Margetić

Beilstein J. Org. Chem. 2019, 15, 1313–1320, doi:10.3762/bjoc.15.130

• demonstrate that quinones could be prepared by simple one-pot FC protocols in the case of reactive aromatics. In situ Raman spectroscopy [60] was applied to study mechanistic aspects of the solid state reaction of phthalic anhydride with p-xylene. Raman spectra were simulated and positions of signals for

• transient reactive intermediates were predicted by density functional theory method B3LYP/6-31G* (Supporting Information File 1) [61]. The stretching of the +C≡O bond of the acylium ion was predicted to be at about 2300 cm−1. Raman spectroscopy revealed that the complexation of phthalic anhydride with AlCl3

Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation

• Sebastian Haferkamp,
• Andrea Paul,
• Adam A. L. Michalchuk and
• Franziska Emmerling

Beilstein J. Org. Chem. 2019, 15, 1141–1148, doi:10.3762/bjoc.15.110

• reaction environment. It was subsequently demonstrated how a combination of different in situ methods can provide more thorough investigation of mechanochemical reaction mechanisms [14][15][16]. Of particular benefit to synthetic reactions, such as C–C bond formation [17][18], the use of Raman spectroscopy

• is of great interest. The characteristic bands are usually well separated, and the course of the reaction can be followed easily. The advantage of Raman spectroscopy was recently demonstrated [19], where its combination with XRPD allowed monitoring of the mechanochemically catalyzed Knoevenagel

• is difficult to employ reliably Raman spectroscopy for in situ mechanochemical data. Hence, despite its availability in many laboratories, in situ real-time monitoring of mechanochemistry by Raman scattering has remained underexplored. We therefore sought to identify a means to resolve this issue

Synergistic electrodeposition of bilayer films and analysis by Raman spectroscopy

• Saadeldin E. T. Elmasly,
• Luca Guerrini,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Neil J. Findlay,
• Karen Faulds and
• Peter J. Skabara

Beilstein J. Org. Chem. 2018, 14, 2186–2189, doi:10.3762/bjoc.14.191

• successfully demonstrated. Moreover, careful control of the electrochemical conditions allows the degree of doping to be effectively altered for one of the polymer layers. Raman spectroscopy confirmed the formation and doped states of the PEDOT/PEDTT bilayer. The electrochemical deposition of a bilayer

• PEDOT layer remains predominantly doped. In order to support the formation of a PEDOT/PEDTT bilayer using this technique and to clarify the nature of doping in the two layers, freshly fabricated bilayers (using 10−4 M monomer solution) were grown on ITO and analysed by Raman spectroscopy, alongside

• bilayer (Figure S4a, Supporting Information File 1), it has been shown that Raman spectroscopy is an effective technique to confirm the coating of PEDTT onto the doped PEDOT layer. Additionally, the presence of features that are characteristic of neutral PEDTT in the Raman spectrum of the de-doped bilayer

Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• the reaction and generation of highly luminescent compounds which hindered in situ monitoring by Raman spectroscopy. However, in situ monitoring of the milling processes was enabled by using Cu(0) catalysts in the form of brass milling media which offered a direct insight into the reaction pathway of

• states for the mechanochemical CuAAC reaction of target quinoline derivatives and p-substituted phenyl azides. We have also investigated the effect of the p-substituent in the azide on the reaction progress and yields. Direct monitoring by in situ Raman spectroscopy was used to gain an insight into the

• while monitoring the reaction course by in situ Raman spectroscopy [45]. While this methodology was already successfully applied for establishing mechanistic and kinetic details in the formation of cocrystals [46], coordination and organometallic compounds [47], it proved to be especially valuable for

Structural diversity in the host–guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies

• Magdalena Ceborska,
• Magdalena Zimnicka,
• Aneta Aniela Kowalska,
• Kajetan Dąbrowa and
• Barbara Repeć

Beilstein J. Org. Chem. 2017, 13, 2252–2263, doi:10.3762/bjoc.13.222

• equivalent – methyl α-D-glucopyranoside – was investigated for a deeper understanding of the type of host–guest interactions. Solid state studies of PTX/CDs were performed using FTIR–ATR and Raman spectroscopy techniques. Keywords: antifolate; cyclodextrin; hydrophobic interactions; inclusion complexes

• identification of guest–host interactions is possible [17][18]. Any changes in the band position as well as increasing or decreasing of its intensity indicate complex formation. In that sense Raman spectroscopy emerges as an important technique for studying host–guest interactions, in particular for verifying if

• PTX into β-CD and γ-CD cavities. Raman spectroscopy of CD/PTX complexes It is known that the Raman spectrum of the physical mixture of the CD-host and guest molecules shows spectral features almost identical with guest molecule [27][28]. That is due to the usually very small intensity of observed

The effect of milling frequency on a mechanochemical organic reaction monitored by in situ Raman spectroscopy

• Patrick A. Julien,
• Ivani Malvestiti and
• Tomislav Friščić

Beilstein J. Org. Chem. 2017, 13, 2160–2168, doi:10.3762/bjoc.13.216

• milling frequency on the course of a mechanochemical organic reaction conducted using a vibratory shaker (mixer) ball mill. The use of in situ Raman spectroscopy for real-time monitoring of the mechanochemical synthesis of a 2,3-diphenylquinoxaline derivative revealed a pronounced dependence of chemical

• : green chemistry; mechanism; mechanochemistry; milling; monitoring; Raman spectroscopy; Introduction Over the past decade, mechanochemical reactions [1][2][3][4], i.e., chemical transformations induced or sustained through the application of mechanical force in the form of grinding, milling and shearing

• spectroscopy to investigate how the choice of base influences the course of a base-catalysed nucleophilic substitution reaction [39]. Raman spectroscopy is particularly well-suited for monitoring and tracking organic reactions. It is a generally accessible and inexpensive, with an output based on changes to

Mechanochemical Knoevenagel condensation investigated in situ

• Sebastian Haferkamp,
• Franziska Fischer,
• Werner Kraus and
• Franziska Emmerling

Beilstein J. Org. Chem. 2017, 13, 2010–2014, doi:10.3762/bjoc.13.197

• .13.197 Abstract The mechanochemical Knoevenagel condensation of malononitrile with p-nitrobenzaldehyde was studied in situ using a tandem approach. X-ray diffraction and Raman spectroscopy were combined to yield time-resolved information on the milling process. Under solvent-free conditions, the reaction

• combined X-ray diffraction and Raman spectroscopy measurements in a tandem approach. Our investigations reveal that the formation of the crystalline product begins after 36 min and is completed after 50 min. The reaction can be described as a melt-mediated reaction since malononitrile melts during the

• ball milling is needed for the completion of the reaction. The ball mill was stopped after 36 minutes and the reaction in the closed jar was monitored with Raman spectroscopy. The data show that under these conditions the reaction to the final product is completed within two hours. Consequently

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• Raman spectroscopy was devised [27]. Finally, these two in situ techniques have been successfully merged to allow simultaneous monitoring of mechanochemical reactions by PXRD and Raman spectroscopy [28][29]. Review Mechanochemical synthesis of (thio)ureas Thioureas In a paper by Kaupp et al. a study on

• nucleophilic aromatic substrates with bis(1-benzotriazolyl)methanethione (26) under ball-milling conditions (Scheme 9) [41]. The application of in situ Raman spectroscopy monitoring of mechanochemical reactions, in combination with solid-state characterization through FTIR-ATR, PXRD and ssNMR analyses

• ureas and guanidines currently available in the market. The supramolecular level of organization of thioureas in the solid-state. The supramolecular level of organization of thioureas in the solid-state. In situ Raman spectroscopy monitoring the synthesis of thiourea 28d in the solid-state. N

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

• Sadaf Hanif,
• Bernd Oschmann,
• Dmitri Spetter,
• Muhammad Nawaz Tahir,
• Wolfgang Tremel and
• Rudolf Zentel

Beilstein J. Org. Chem. 2017, 13, 1693–1701, doi:10.3762/bjoc.13.163

• Raman spectroscopy revealing typical carbonaceous bands, such as the G-band at 1584 cm−1 and the D-band at 1355 cm−1, which is shown in Figure 4c. Furthermore, the residual carbonaceous content was determined by TGA, where the weight loss decreases from 20% (for the block copolymer coated particles) to

• simultaneously introducing an anchor group. Afterwards, we showed the successful in situ synthesis of TiO2 particles with the block copolymer as a ligand on the surface. Raman spectroscopy and TEM images show that PILs are suitable carbon precursors and the herein introduced materials can be further applied as

• detector, JASCO G1362A RID, was used. Poly(methyl methacrylate) (PMMA) was used as calibration standard. TGA was performed with a Perkin Elmer Pyris 6 instrument with an oxygen flow. Raman spectroscopy was conducted with Horiba Jobin Y LabRAM HR spectrometer with a frequency doubled neodymium-doped yttrium

Mechanochemical borylation of aryldiazonium salts; merging light and ball milling

• José G. Hernández

Beilstein J. Org. Chem. 2017, 13, 1463–1469, doi:10.3762/bjoc.13.144

• translucent milling vessels made of poly(methyl methacrylate) (PMMA) with powder X-ray diffraction (PXRD) [6][7], Raman spectroscopy [8], or a combination of both techniques [9]. On the other hand, attempts to combine photo- and mechanical activation to favor chemical processes have been mainly explored in

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• because they can be employed to enhance the intensity of Raman signals close to the NP surface, widely explored in biomedical diagnostics (surface enhanced Raman spectroscopy, SERS). This effect is even more intense when the nanoparticles possess an irregular shape, generating an anisotropic distribution

• efforts, the GAuNPs showed an incremented lectin identification power, at low protein concentrations, enabling an easy tool for sugar–lectin recognition. The glycan–protein interaction has been studied as well employing surface-enhanced Raman spectroscopy (SERS) exploiting AuNP ability in amplifying Raman

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97

• (like UV, IR or Raman spectroscopy) which may be coupled with the reactor jacket flow rate to maintain the desired conversion. The azide and amide streams can be mixed and preheated at 110 °C. The preheated stream can then flow through a copper tubing reactor or a packed bed reactor with copper packings

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• reported syntheses afford CDs with sp2 crystalline or amorphous cores, the team showed that the resultant nanoparticles had an sp3 nanocrystalline core, as determined by HRTEM and Raman spectroscopy. The authors attributed this observation to the relatively mild conditions used. They also showed that the

Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy

• Monica Ferro,
• Franca Castiglione,
• Nadia Pastori,
• Carlo Punta,
• Lucio Melone,
• Walter Panzeri,
• Barbara Rossi,
• Francesco Trotta and
• Andrea Mele

Beilstein J. Org. Chem. 2017, 13, 182–194, doi:10.3762/bjoc.13.21

• condensation reaction of the OH groups of the glucopyranose units of cyclodextrins (CD) with a poly-functional cross-linking agent [3]. CDNS have been characterized, in the solid state, by a repertoire of physical methods such as solid-state 13C CP-MAS NMR, FTIR and Raman spectroscopy [4][5][6]. Moreover, in