Organometallic vs organic photoredox catalysts for photocuring reactions in the visible region

• Aude-Héloise Bonardi,
• Frédéric Dumur,
• Guillaume Noirbent,
• Jacques Lalevée and
• Didier Gigmes

Beilstein J. Org. Chem. 2018, 14, 3025–3046, doi:10.3762/bjoc.14.282

• in a monomer blend. In the case of photopolymerization, a photoinitiating system (PIs) is required to convert light in initiating species. Many factors affect the photopolymerization kinetics. However, the PIs is the most important key factor and that’s why enhancing its properties have drawn many

• with the monomer or a monomer blend. The PI is a component which absorbs light and initiates polymerization alone whereas a photoinitiating system comprises different compounds [8][9][10]. Under irradiation, PI or PIs generate active species: free radicals and/or ions and/or acid. When the active

• polymerization reactions Polymerization reactions whose initiation is induced by photoredox catalysts has been detailed in part 1.4. Representative monomer conversions with different photoredox catalysts and upon different irradiation light for free radical polymerization and for cationic polymerization are

The influence of the cationic carbenes on the initiation kinetics of ruthenium-based metathesis catalysts; a DFT study

• Magdalena Jawiczuk,
• Angelika Janaszkiewicz and
• Bartosz Trzaskowski

Beilstein J. Org. Chem. 2018, 14, 2872–2880, doi:10.3762/bjoc.14.266

• interesting phenomenon, despite its very limited impact on their propensity to form transition metal complexes (Scheme 2) [50]. Many works have been devoted to the study of carbene dimerization and present evidence that mechanism of monomer–dimer equilibrium depends on the balance between the electronic and

• Gibbs free energy difference for the symmetric dimer A. In the case of carbene 3, the Gibbs free energy of dimerization could not be estimated due to instability of the monomer during geometry optimization. Thus, the results indicate higher stability of dimers for all examined NHC, which are in

Copolymerization of epoxides with cyclic anhydrides catalyzed by dinuclear cobalt complexes

• Yo Hiranoi and
• Koji Nakano

Beilstein J. Org. Chem. 2018, 14, 2779–2788, doi:10.3762/bjoc.14.255

• monomer conversion. A variety of lactones and cyclic diesters, such as ε-caprolactone, β-propiolactone, lactic acid (LA), and glycolide have been used for the ROP. However, the employable monomers are rather limited, which restricts the range of polymer properties. In view of the aforementioned, the

• ). Monomer scope In order to evaluate the copolymerization scope, the dinuclear cobalt–salen complex (R,R,R,R)-1 and co-catalyst [PPN][OCOC6F5] were employed for the copolymerization of other epoxides with PA (Table 2). 1-Hexene oxide (HO), a terminal epoxide with an expanded alkyl chain, can be

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• SM cross coupling followed by RCM as key steps [50]. To this end, dibromo compound 123 was subjected to diallylation by using allylboronate ester 12 to form the diallyl derivative 124 (73%). Treatment of compound 124 with G-I catalyst 1 gave unsaturated dimer 126 (30%) and monomer 125 (15

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

• 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

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• -type arrangement in the dimer [34]. Furthermore, the equilibrium between a paramagnetic monomer and a diamagnetic dimer makes the use of electron paramagnetic resonance (EPR) spectroscopy ideal to follow the dimerization process [36]. Mixed-valence and radical-cation interactions in the solid state are

Evaluation of dispersion type metal···π arene interaction in arylbismuth compounds – an experimental and theoretical study

• Ana-Maria Preda,
• Małgorzata Krasowska,
• Lydia Wrobel,
• Philipp Kitschke,
• Phil C. Andrews,
• Jonathan G. MacLellan,
• Lutz Mertens,
• Marcus Korb,
• Tobias Rüffer,
• Heinrich Lang,
• Alexander A. Auer and
• Michael Mehring

Beilstein J. Org. Chem. 2018, 14, 2125–2145, doi:10.3762/bjoc.14.187

• state can be studied based on monomer distortion, intermolecular interactions of representative dimers and the interaction of one molecule with several of its neighbors. Distance scan for the idealized BiPh3···benzene complex In a previous study on the nature of Bi···π arene interactions in various

• in the solid state of BiPh3. The structures of the studied tetramers are shown in Figures 11, 13, and 15. Subsequently, tetramers were divided into dimeric units that represent specific intermonomer interactions, and can be considered as building blocks of the bulk. Monomer distortion energies

• geometry. Important information on the intermolecular interaction strength within the tetramer is obtained when one monomer is removed from the system. This energy (depicted as Eremove in Figures 11, 13, and 15) contains the interactions with neighboring molecules and also possible long-range interactions

A self-assembled photoresponsive gel consisting of chiral nanofibers

• Lei Zou,
• Dan Han,
• Zhiyi Yuan,
• Dongdong Chang and
• Xiang Ma

Beilstein J. Org. Chem. 2018, 14, 1994–2001, doi:10.3762/bjoc.14.174

• glutamic acid skeleton, containing azobenzene as a photoresponsive group and ureidopyrimidinone (UPy) as a connection site, was designed and synthesized. The monomer is capable of forming an organogel in nonpolar organic solvents and different types of nanostructures in other solvents. The state of the gel

• of compound 3 in benzene that was investigated previously. Conclusion We have synthesized a novel chiral compound containing azobenzene as the photoresponsive group and UPy as the connection site. The monomer was capable of forming chiral nanostructures and a low-molecular-weight organogel in

• nonpolar organic solvents. The monomer also can form different types of nanostructures in different solvents, and the kind of solvent was found to be crucial for the chirality of the assembled structure. The gel-to-sol process could also be modified by shaking and UV light. The rheological behavior of the

The phenyl vinyl ether–methanol complex: a model system for quantum chemistry benchmarking

• Dominic Bernhard,
• Fabian Dietrich,
• Mariyam Fatima,
• Cristóbal Pérez,
• Hannes C. Gottschalk,
• Axel Wuttke,
• Ricardo A. Mata,
• Martin A. Suhm,
• Melanie Schnell and
• Markus Gerhards

Beilstein J. Org. Chem. 2018, 14, 1642–1654, doi:10.3762/bjoc.14.140

• are shown in Figure 3. Besides methanol monomer, methanol dimer and a signal clearly attributed to a larger cluster, only a single, reasonably narrow absorption at 3625 cm−1 is observed. It can be attributed to mixed dimers of MeOH with PVE and allows for a single rigorous conclusion, due to the

• , one-color R2PI spectra were recorded in the range of 36100–37600 cm−1 (cf. Figure S1 in Supporting Information File 1). While the R2PI spectrum of the PVE monomer shows well-resolved vibrational progressions (cf. Figure S1a, Supporting Information File 1), the spectrum of the solvent aggregate is

• –alcohol clusters before [20][21][22]. Comparing the vertical excitation energies for the different isomers with the experimental excitation energy of 36885 cm–1 yields the best agreement for the OH–O or OH–O’ isomer, which also show a significantly blue-shifted S1←S0 transition compared to the PVE monomer

Glycosylation reactions mediated by hypervalent iodine: application to the synthesis of nucleosides and carbohydrates

• Yuichi Yoshimura,
• Hideaki Wakamatsu,
• Yoshihiro Natori,
• Yukako Saito and
• Noriaki Minakawa

Beilstein J. Org. Chem. 2018, 14, 1595–1618, doi:10.3762/bjoc.14.137

• cell viability, their biological synthesis, including the synthesis of their monomer units, e.g., nucleotides, is highly regulated. Damage to these vital molecules often results in congenital disease with ultimately fatal consequences [2][3]. Accordingly, the study of polymers and their biosynthesis is

Drug targeting to decrease cardiotoxicity – determination of the cytotoxic effect of GnRH-based conjugates containing doxorubicin, daunorubicin and methotrexate on human cardiomyocytes and endothelial cells

• Livia Polgár,
• Eszter Lajkó,
• Pál Soós,
• Orsolya Láng,
• Marilena Manea,
• Béla Merkely,
• Gábor Mező and
• László Kőhidai

Beilstein J. Org. Chem. 2018, 14, 1583–1594, doi:10.3762/bjoc.14.136

• bifunctional daunorubicin-GnRH-III conjugates without spacer and modified in position 4 with Lys; (e) {GnRH-III(Dau=Aoa-C)}2 dimer and conjugates modified in position 4 with N-MeSer; (f) GFLG or YRRL spacer containing monomer and dimer conjugates (g) GnRH-III conjugates containing methotrexate and daunorubicin

• ) GFLG or YRRL spacer containing monomer and dimer conjugates; (g) GnRH-III conjugates containing methotrexate and daunorubicin. Comparative study of cytotoxic effects and cardiotoxicity elicited by GnRH-based antitumor compounds (1–15) and reference substances (AN-152, Dox, Dau, Mtx). IC50 values show

Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

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

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

• , V.le delle Scienze ed. 17, 90128 Palermo, Italy 10.3762/bjoc.14.127 Abstract New calixarene-based nanosponges (CaNSs), i.e., hyper-reticulated polymers constituted by calixarene monomer units joined by means of bis(1,2,3-trialzolyl)alkyl linkers, were synthesized, characterized and subjected to

• ]) between a heptakis(6-azido-6-deoxy)-β-cyclodextrin and a tetrakis(propargyloxy)calix[4]arene [11][31][32]. In this way, a random disposition of the co-monomer units linked by 1,2,3-triazole units is achieved. The obtained CyCaNSs benefit from several advantages. First, the properties of the material can

• models. Results and Discussion Synthesis and FTIR characterization The synthesis of materials CaNS1-CaNS4 was first attempted according to the procedure already optimized for the synthesis of CyCaNS co-polymers [11], i.e., by reacting the monomer precursor Ca-OP with an equivalent amount of each alkyl

Steric “attraction”: not by dispersion alone

• Ganna Gryn’ova and
• Clémence Corminboeuf

Beilstein J. Org. Chem. 2018, 14, 1482–1490, doi:10.3762/bjoc.14.125

• functional theory [39], post-Hartree–Fock [40][41], symmetry adapted perturbation theory (SAPT) [42][43][44][45][46] data or to a combination of the latter two (e.g., the monomer electron density force field, MEDFF) [47]. The latter approach has been subsequently exploited in the machine learning

• representative class (II) and class (III) systems: tetracene (7) and its fully saturated analogue, perhydrotetracene (10, Figure 5A and B). For each monomer, four types of dimers were compared – perfectly stacked (i.e., the frozen dimer) and shifted transversally, laterally and in both directions by approx. half

• these effects even when modeling saturated hydrocarbons and provides the context for the underperformance of the molecular mechanics force fields, commonly applied to aliphatics. Computational Details Geometries of the isolated monomer cores were optimized at the M06-2X/def2-SVP level using Gaussian 09

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• acid, mesoxalic acid and 1,3-dihydroxyacetone (DHA). These products are conventionally obtained by oxidation using rather unselective oxidants. Especially DHA is of great interest due to its use in the cosmetic industry, as a precursor for further value-added fine chemicals [9] and as a monomer for

Oligonucleotide analogues with cationic backbone linkages

• Melissa Meng and
• Christian Ducho

Beilstein J. Org. Chem. 2018, 14, 1293–1308, doi:10.3762/bjoc.14.111

• of DNG oligomers were introduced. They enabled chain elongation either in the 5'→3' [52] or 3'→5' [53] direction, respectively. Starting from protected 3',5'-dideoxy-5'-amino-3'-azidothymidine 21, the 5'→3' route was based on the synthesis of the diamino intermediate 22 and thiourea monomer 23, which

• monomer 30 to the corresponding carbodiimide 31 (Scheme 3). Using long-chain alkylamine controlled pore glass (CPG) loaded with 5′-amino-5′-deoxythymidine (32) as solid phase, the reaction cycle started with the guanidine-forming coupling of 31 and 32 to give 33, followed by acidic cleavage of the MMTr

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

Correlation effects and many-body interactions in water clusters

• Andreas Heßelmann

Beilstein J. Org. Chem. 2018, 14, 979–991, doi:10.3762/bjoc.14.83

• individual terms with respect to the interaction energy operator. In this work all terms in Equation 5 have been computed using EXX monomer wave functions. Moreover, a time-dependent EXX (TDEXX) response approach was used to compute the second-order interaction energy contributions [53][54][55][56][57][58

• can be determined by combining two monomers to one single (pseudo-)monomer and calculating the interaction with the remaining one. In case of the trimer three different possibilities exist: where the term Δ2(AB − C) now denotes the interaction of the combined system AB with monomer C. As can be easily

• -body interaction energy counterparts but should rather be interpreted as the changes of the electrostatic and induction interactions due to the perturbations by another monomer in the trimer. Accordingly, one may interpret the electrostatic contribution in Figure 8 as an induction effect and the

Enzyme-free genetic copying of DNA and RNA sequences

• Marilyne Sosson and
• Clemens Richert

Beilstein J. Org. Chem. 2018, 14, 603–617, doi:10.3762/bjoc.14.47

• replication has been reviewed [11]. Ligation reactions will not be discussed further here, as they are limited in their scope, in terms of sequences, whereas monomer-based copying may be used for any given sequence, at least in principle. Rather, we will focus on copying with mononucleotides, for which early

• examples can also be found in the literature of the 1960s [12]. The early monomer-based work on copying RNA focused on oligomerization of nucleotides on homosequences as templates [13][14]. The best results were observed for poly(C) as template, the 2-methylimidazolide of guanosine as activated monomer

• . Instead, the base pairing between individual bases of an incoming nucleotide and the templating base must suffice to attract the monomer to the extension site. The stability of different base pairs varies, and so does the templating effect of different stretches of the template sequence. Using random

Preparation of trinucleotide phosphoramidites as synthons for the synthesis of gene libraries

• Ruth Suchsland,
• Bettina Appel and
• Sabine Müller

Beilstein J. Org. Chem. 2018, 14, 397–406, doi:10.3762/bjoc.14.28

• -protected monomer. Upon selective removal of either the 5'-O-DMTr group or the 3'-O-levulinoyl group, the dimer was extended in 5' or 3' direction [26]. All other reports describe strategies, where the dimers are extended unidirectional, either in 5'-direction [25][26][27][29][30] or 3'-direction [31][32

• detritylation and coupling of the third monomer. The release of the trimer in fully protected form from the support was achieved by hydrogenation with Pd/C (10%) in tetrahydrofurane (THF) for 40 h at room temperature. Three fully protected trimers were prepared this way with isolated yields in the range of 44

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

• background and good response with DNA, as well as offering an excellent specificity [65]. In addition to fluorophore-quencher interactions, FRET [66] and pyrene monomer–excimer switching [67][68] have been employed as alternative mechanisms for inducing fluorescence changes in the DNA probes. The FRET and

• monomer–excimer switching approaches have some advantages over fluorescence quenching because of the large Stokes shifts and the ability to measure the signals at two different wavelengths, thereby providing a means for self-referencing. Furthermore, unlike the fluorophore-quencher beacons, the FRET and

• monomer–excimer switching beacons are also fluorescent in the unbound state, and therefore it is possible to monitor the success of cellular delivery. In the case of pyrene monomer–excimer switching, the long fluorescence lifetime of the pyrene excimers allows facile elimination of background signals from

Fluorescent nucleobase analogues for base–base FRET in nucleic acids: synthesis, photophysics and applications

• Mattias Bood,
• Sangamesh Sarangamath,
• Moa S. Wranne,
• Morten Grøtli and
• L. Marcus Wilhelmsson

Beilstein J. Org. Chem. 2018, 14, 114–129, doi:10.3762/bjoc.14.7

• protection and phosphitylation using CEP-Cl generated the fully protected monomer ready for solid-phase synthesis [50]. The complete synthesis of the RNA building block of tCO was in this way achieved over five steps with a total yield of 28%, improved from the four step DNA building block synthesis of tCO

• first reported by our group, was our initial adenine analogue candidate [53]. It stabilizes the native B-form DNA and is selective for base pairing with thymine. The emissive properties are decent both for the monomer (Φf = 6.8%) and inside DNA even though the quantum yield is quenched in the latter

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

• Marco Russo,
• Daniele La Corte,
• Annalisa Pisciotta,
• Serena Riela,
• Rosa Alduina and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2751–2763, doi:10.3762/bjoc.13.271

• hand, for the samples prepared at lower pH values the optical activities of the supernatant liquor after centrifugation decrease accounting for the progressive subtraction of the AmCD from the solution. Indicating with nr the average molar ratio between the AmCD and the monomer units of alginate in the

• substance (99.5 mg) was dissolved in warm water and after cooling to rt the volume was adjusted to 20 mL. Finally, the solution was filtered through a 0.45 μ Millipore® filter. For the sake of clarity, the concentration (normality) was calculated according to the formula weight of the monomer unit (C6H7O6Na

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

• as a ditopic monomer of the AB type with groups A and B undergoing an association of 1:1. However, a number of alternate or competing interactions may occur, as mentioned above, γ-CD is known to form also inclusion complexes of 2:1 stoichiometry and formation of cyclic supramolecular structures my

Synthesis of naturally-derived macromolecules through simplified electrochemically mediated ATRP

• Paweł Chmielarz,
• Tomasz Pacześniak,
• Katarzyna Rydel-Ciszek,
• Izabela Zaborniak,
• Paulina Biedka and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2017, 13, 2466–2472, doi:10.3762/bjoc.13.243

• , Supporting Information File 1) [57]. This potential cycle was repeated three times, efficiently increasing the monomer conversion to 25, 51, and then to 75% during active periods (Figure 3a). MW steadily increased during the “on” periods, while no low-MW polymers were detected (Figure 3b and Figure S12b

• purification (in CDCl3). Synthesis of PtBA homopolymers grafted from quercetin-based macroinitiator via seATRP under constant potential conditions; (a) Mn and Mw/Mn vs monomer conversion, and (b) GPC traces of tBA polymerization and their evolution over time. Reaction conditions: [tBA]/[QC-Br5 (per 5

• with respect to monomer conversion. Reaction conditions are identical to those stated in Figure 2. Summary of quercetin-based pseudo-star polymers synthesis by seATRP. Supporting Information Supporting Information File 458: Experimental section including NMR spectra, first-order kinetic plot, GPC

Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines

• Satoru Mori and
• Norio Shibata

Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224

• . Furthermore, the same structural dimer of TFEO-Pc and tert-butyl-substituted phthalocyanine 7b was synthesized by the Suzuki coupling reaction. These dimers show a new absorption peak in the longer wavelength region than the Q band which is not observed in the monomer. This suggests intramolecular electronic