Synthesis Of Oligomers Research Articles

Properties of phosphoramide benzoazole oligonucleotides (PABAOs). II. Structure and hybridization efficiency of N-benzoxazole derivatives

New phosphate-modified nucleic acid derivatives are of great significance in basic research and biomedical applications. We have recently developed a new class of phosphoramide benzoazole oligonucleotides (PABAOs). In this work, th properties of N-benzoxazole oligodeoxyribonucleotides have been thoroughly examined. We have demonstrated the convenient automated solid-phase synthesis of oligomers with a different number of modifications (up to six) at various positions. Optical properties, thermal stability, structure, and dynamics of PABAO/DNA complexes have been investigated. The N-benzoxazole-modified phosphate group is uncharged at neutral pH and has a pKa value of 8.52. Structural analysis performed by the CD spectroscopy and MD simulation indicate B-form of PABAO/DNA duplexes. The thermal stability of PABAO/DNA complexes bearing N-benzoxazole is reduced by 2.5–6.2° per modification compared to native duplexes at standard and near physiological buffer conditions. The performed study underlines a great potential of phosphoramide benzoazole oligonucleotides for basic research, applied sciences, and biotechnology.

Generalization of the Carothers equation for linear step growth polymers

In the synthesis of linear step-growth polymers molecular weight control is accomplished through the addition of a controlled amount of monomer carrying the functional group B in excess (B-B or H-B types). The Carothers equation is used to calculate average chain lengths. This paper extends the analysis of chain lengths to include the effect of monofunctional monomers carrying the limiting group A (H-A), allowing the systematic analysis of complex systems containing both bifunctional and monofunctional species of any type (A-A, B-B, H-B and H-A). This refinement is particularly relevant for the synthesis of oligomers from systems with complex feed composition.

Harnessing IrAAC and SuFEx for the Efficient Synthesis of Sequence-Defined Oligomers with Diverse Side Groups

Harnessing IrAAC and SuFEx for the Efficient Synthesis of Sequence-Defined Oligomers with Diverse Side Groups

An investigation of the enzymatic oligomerization of nitro-substituted phenylene diamine: Thermal and fluorescence properties

2-nitro-p-phenylenediamine, an aromatic diamine, was studied for its oxidative oligomerization with H2O2 using enzyme-catalyzed oligomer synthesis. Characterization of molecular structures was performed utilizing ultraviolet-visible (UV-Vis) spectrophotometer, Fourier-transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) techniques, identifying phenazine-bridged oligomer resulting from the enzymatic oligomerization process. Based on the results of gel permeation chromatography (GPC) analysis, the synthesized compound was identified as being in an oligomeric form. Conversely, the number of repeating units, as determined by Mw, was found to be 28. The solvent effect on the optical features of the synthesized oligomer in polar solvents was analyzed. The degradation of phenazine-type structures in the oligomer occurred at higher temperatures than that of the monomer. Under visible light excitation, the oligomer exhibited green light emission with a quantum yield (QY) of 6.2% in N,N-dimethylformamide (DMF). 2-nitro-p-phenylenediamine was readily oxidized into an oligomer with ortho-coupled constitutional units, having a lower electrochemical band gap than the monomer, via the enzymatic oligomerization route. Scanning electron microscopy revealed that enzyme-catalyzed oxidation of monomers exhibited a spongy morphology with some pores

On-Surface Synthesis of 1D and 2D π-Conjugated Polymers from Heterotetrabromo-P-quinodimethanes (HTBQs)

Molecules bearing gem-dibromoolefines functionalities have been employed in wet chemistry as intermediates in the well-known Corey-Fuchs homologation of carbonyls to alkynes. This gem-dibromoolefines can be embedded into tetrabromo-p-quinodimethanes (TBQs), which efficiently undergo dehalogenative homocoupling on coinage metal surfaces, namely Au(111) and Ag(111), forming one-dimensional (1D) acene and periacene π-conjugated polymers able to exhibit non-trivial topological properties.[1,2]However, the synthesis of more complex π-conjugated polymers to determine the scope of this new reaction, as well as the synthesis of two-dimensional (2D) polymers by following this chemical methodology are still important challenges. In this context, new dimeric TBQs have been synthesized by wet chemical protocols for their further use in the synthesis of double-strand oligomers. Interestingly, the new systems exhibit many defects, due to the intrinsic nature of the synthesized precursors.[3] In this work, we firstly take advantage of the introduction of heteroatoms at the edges of the monomers in order to grow 1D new π-conjugated polymers which, eventually, collapse into amazing large 2D networks by non-covalent interactions. Moreover, when suitable designed TBQs with both the presence of heteroatoms and steric hindrance, unprecedented 1D and covalently linked 2D π-conjugated polymers are formed. These results have allowed the study of new topologically non-trivial polymers which will be presented and discussed in this communication.[1] Cirera, B., Sánchez-Grande, A., de la Torre, B., Santos J. et al. Nat. Nanotechnol. 2020, 15, 437–443.[2] González-Herrero, H., Mendieta-Moreno, J. I., Edalatmanesh, S., Santos, J. et al. Advanced Materials 2021, 33, 2104495.[3] Vicent, D. J., Perez-Escribano, M. et al. Chem. Sci., 2023, 14, 10112-10120.

GUANIDINE-CONTAINING ALIPHATIC OLIGOMERS WITH BACTERICIDAL ACTIVITY

A method for the synthesis of reactive aliphatic guanidine oligomers (GO) of different MM by the reaction of oligomeric oxyalkylaliphatic diepoxide with guanidine by varying the ratio of the starting components with subsequent neutralization of the obtained product with hydrochloric acid was developed. A characteristic feature of the structure of the obtained GO oligomers is their amphiphilicity, with the presence of hydroxy-containing guanidine fragments both at the ends and inside the chain. The obtained oligomers are reactive to further chemical transformations. The chemical structure of GO was characterized by FTIR and 1H-NMR spectroscopy, molecular weight was determined by liquid chromatography and titration data. The bactericidal properties of aliphatic guanidine oligomers against a number of gram-positive (Micrococcus luteus, Rhodococcus erythropolis, Rhodococcus rubber, Bacillus megaterium, Bacillus subtilis, Bacillus cereus) and gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Serratia marcescen), depending on the MW of GO were investigated. The minimum inhibitory concentration of aliphatic guanidine oligomers against the studied bacterial strains was determined. It has been shown that the oligomer with the highest content of guanidine fragments has the greatest bactericidal activity and, accordingly, the lowest minimum inhibitory concentration against gram-positive and gram-negative bacteria. The reactive guanidine oligomers obtained by analogy with polyhexamethylene guanidine chloride can be recommended as substances with biocidal and fungicidal properties. In addition, the inherent reactivity of the synthesized GO makes them promising for obtaining various new types of polymers and composites based on them.

Synthesis and Characterization of Furan-Based Methacrylate Oligomers Containing the Imine Functional Group for Stereolithography.

Herein, a furan-based methacrylate oligomer (FBMO) featuring imine functional groups was synthesized for application in stereolithography. The preparation involved the imination reaction of 5-hydroxymethylfurfural (5-HMF) and amino ethanol. Utilizing 5-HMF as a sustainable building block for furan-based polymers, FBMO was formulated and subsequently integrated into photosensitive resin formulations along with methacrylate-containing diluents, such as PEGDMA and TEGDMA. The synthesized furan-based methacrylate oligomers underwent comprehensive characterization using FTIR, 1H NMR spectroscopy, and size exclusion chromatography. The impact of methacrylate-containing diluents on various properties of the formulated resins and the resulting 3D-printed specimens was systematically evaluated. This assessment included an analysis of rheological behavior, printing fidelity, mechanical properties, thermal stability, surface morphology, and cytotoxicity. By adjusting the ratios of FBMO to methacrylate-containing diluents within the range of 50:50 to 90:10, the viscosity of the resulting resins was controlled to fall within 0.04 to 0.28 Pa s at a shear rate of 10 s-1. The 3D-printed specimens exhibited precise conformity to the computer-aided design (CAD) model and demonstrated compressive moduli ranging from 0.53 ± 0.04 to 144 ± 6.70 MPa, dependent on the resin formulation and internal structure. Furthermore, cytotoxicity assessments revealed that the 3D-printed specimens were noncytotoxic to porcine chondrocytes. In conclusion, we introduce a new strategy to prepare the furan-based methacrylate oligomer (FBMO) and 3D-printed specimens with adjustable properties using stereolithography, which can be further utilized for appropriate applications.

Facile one-pot synthesis and characterization of castor oil-based acrylate oligomer for UV curable wood coating

Facile one-pot synthesis and characterization of castor oil-based acrylate oligomer for UV curable wood coating

Design and Synthesis of Ethynyl-Linked Oligomers Emitting Variously Colored Fluorescence

Design and Synthesis of Ethynyl-Linked Oligomers Emitting Variously Colored Fluorescence

Double polymerization synergy to sharpen structural toughness of melamine resin foam

Melamine resin foam (Mfoam) is a porous heat-cured amino resin material with excellent flame retardancy, thermal insulation, and noise reduction capabilities. However, some fatal shortcomings like easy brittle breakage, easy powderization and poor toughness directly limit its wide application and further development. In this paper, hydroxypropyl acrylate (HPA) was used to participate in the synthesis of melamine resin oligomers (Moli) in order to link the vinyl group to molecular skeleton. As a result, both vinyl and hydroxymethyl active groups are present in Moli which provide Moli with the ability to perform free radical polymerization reaction and polycondensation polymerization reaction, named double polymerization reaction (DPR), and produce synergistic effects to form a structurally toughened melamine resin foam (TMfoam). The research shows that the scheme can effectively solve the problems of brittle breakage and easy powderization of Mfoam. And under apparent density (Ad) of 40 ± 2 kg/m3, the prepared TMfoam has good toughness, with the bending strength of 405.2 kPa, the compression strength of 352.5 kPa, and the pulverization rate of 1.18 %. Meanwhile, the combustion grade of the TMfoam can reach to B1 grade, and the thermal conductivity is 0.0328 W/(m·K). Also the absorption coefficient of TMfoam can reach up to 0.92 under frequency of 3045 Hz. All the facts indicate that the DPR showed good synergistic effect during the forming and setting stages from Moli to TMfoam. At the same time, the bubble chamber of TMfoam changes from metastable state to stable state, and its strength and toughness are significantly improved in step. This research has great and practical significance for expanding the wide application of Mfoam type materials.

On the isomeric purity of endcap molecules in cholesteric liquid crystal oligomers for near-infrared thermochromic coatings

ABSTRACT Structurally coloured responsive materials provide an interesting avenue for the development of autonomous temperature regulating window films. One interesting class of such thermochromic materials is cholesteric liquid crystals. However, cholesteric liquid crystals have rarely been applied in coatings for smart window applications. In this work, we report the synthesis of endcapped cholesteric liquid crystal oligomers and its application as near-infrared thermochromic coatings for windows. Two isomerically pure monoacrylate endcapping molecules and its isomeric mixture are synthesised. The molecules are used to synthesise a variety of endcapped cholesteric liquid crystal oligomers to study the effect of the isomeric purity on the thermochromic properties of the coatings. It is found that while the oligomers are almost identical in composition and phase behaviour, only one isomer produces a clear transparent coating, highlighting the significance of minute isomeric differences. Remarkably, the thermochromic behaviour of the coatings for all oligomers is the same. The best performing oligomer is able to reversibly blueshift by 250 nanometres when heated from room temperature to 100°C, opening the way of cholesteric liquid crystals for use in temperature regulating window films.

Synthesis and Design of Metalloporphyrin Oligomers with Temperature-Assisted Spectral-Luminescent Properties

Synthesis and Design of Metalloporphyrin Oligomers with Temperature-Assisted Spectral-Luminescent Properties

Dehydro[12]- and [18]annulene-Fused Ball-Shaped Ruthenium Complex Oligomers: Synthesis, Aromatic/Antiaromatic Effect, and Symmetry for Near-Infrared Optical Properties.

The appropriate arrangement of near-infrared (NIR) chromophores allows for the modification of the peak wavelength in the NIR region and efficient use of NIR light. However, the preparation of novel NIR chromophores using simple procedures remains a formidable challenge. Herein, we report the synthesis of ball-shaped ruthenium complex oligomers. The metal complexes can be synthesized in a single step and interact strongly with NIR light. Alkyne-substituted low-symmetry ball-shaped ruthenium complexes were synthesized and subjected to Eglinton coupling to obtain dehydro[12] and [18]annulene-fused dimers and trimers. Fine-tuning of the reaction conditions led to the selective synthesis of the target oligomers. NMR spectroscopy confirmed that the 18π-aromatic and 12π-antiaromatic properties of the annulene influenced the ruthenium complex chromophore, and magnetic circular dichroism spectroscopy showed changes in the electronic structure of their excited state owing to molecular-symmetry differences. The absorption coefficient in the NIR region of the absorption spectra of the oligomers increased significantly, supporting the efficient use of light by oligomerization. The formation of oligomers using ball-shaped metal complexes is a simple and effective strategy for controlling NIR optical properties.

On-Surface Synthesis of Helicene Oligomers.

We report on-surface synthesis of heterochiral 1D heptahelicene oligomers after deposition of a racemic heptahelicene monomer on an Au(111) surface followed by Ullmann coupling under ultrahigh vacuum conditions. Structure, chirality and mode of adsorption of the resulting dimers to octamers are inferred from the scanning probe microscopy and theoretical calculations.

Selective Duplex Formation in Mixed Sequence Libraries of Synthetic Polymers.

Recognition-encoded melamine oligomers (REMO) are synthetic polymers that feature an alternating 1,3,5-triazine-piperazine backbone and side-chains equipped with either a phenol or phosphine oxide recognition unit. An automated method for the solid-phase synthesis (SPS) of REMO of any specified sequence has been developed starting from dichlorotriazine monomer building blocks. Complementary homo-oligomers with either six phenols or six phosphine oxides were synthesized and shown to form a stable duplex in nonpolar solvents by NMR denaturation experiments. The duplex was covalently trapped by equipping the ends of the oligomers with an azide and an alkyne group and using a copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction. The SPS methodology was adapted to synthesize mixed sequence libraries by using a mixture of two different dichlorotriazine building blocks in each coupling cycle of an oligomer synthesis. The resulting libraries contain statistical mixtures of all possible sequences. The self-assembly properties of these libraries were screened by using the CuAAC reaction to trap any duplexes present. In mixed sequence libraries of 6-mers, the trapping experiments showed that only sequence-complementary oligomers formed duplexes at micromolar concentrations in dichloromethane. The automated synthesis approach developed here provides access to large libraries of mixed sequence synthetic polymers, and the covalent trapping experiment provides a convenient tool for screening functional properties of mixtures. The results suggest high-fidelity sequence-selective duplex formation in mixtures of 6-mer sequences of the REMO architecture.

High-Throughput Synthesis, Purification, and Application of Alkyne-Functionalized Discrete Oligomers.

The development of synthetic oligomers as discrete single molecular entities with accurate control over the number and nature of functional groups along the backbone has enabled a variety of new research opportunities. From fundamental studies of self-assembly in materials science to understanding efficacy and safety profiles in biology and pharmaceuticals, future directions are significantly impacted by the availability of discrete, multifunctional oligomers. However, the preparation of diverse libraries of discrete and stereospecific oligomers remains a significant challenge. We report a novel strategy for accelerating the synthesis and isolation of discrete oligomers in a high-throughput manner based on click chemistry and simplified bead-based purification. The resulting synthetic platform allows libraries of discrete polyether oligomers to be prepared and the impact of variables such as chain length, number, and nature of side chain functionalities and molecular dispersity on antibacterial behavior examined. Significantly, discrete oligomers were shown to exhibit enhanced activity with lower toxicity compared with traditional disperse samples. This work provides a practical and scalable methodology for nonexperts to prepare libraries of multifunctional discrete oligomers and demonstrates the advantages of discrete materials in biological applications.

Continuous Polymer Synthesis and Manufacturing of Polyurethane Elastomers Enabled by Automation.

Connecting polymer synthesis and processing is an important challenge for streamlining the manufacturing of polymeric materials. In this work, the automated synthesis of acrylate-capped polyurethane oligomers is integrated with vat photopolymerization 3D printing. This strategy enabled the rapid manufacturing of a library of polyurethane-based elastomeric materials with differentiated thermal and mechanical properties. The automated semicontinuous batch synthesis approach proved enabling for resins with otherwise short shelf lives because of the intimate connection between synthesis, formulation, and processing. Structure-property studies demonstrated the ability to tune properties through systematic alteration of cross-link density and chemical composition.

Synthesis of unsaturated polyurethane oligomer and its application in the 3D printing of composite solid propellants

Propellants are the main source of energy for internal ballistic processes. The use of 3D printing technology is expected to produce propellants with complex geometries. However, limited by the properties of existing printable resins, the mechanical properties of 3D-printed propellants make it difficult to meet the requirements for use. This study deals with the structural design, synthesis, and properties of an unsaturated polyurethane resin (PUA). A photoinitiator was added to this polyurethane resin and a photo-curable elastomer was successfully prepared under UV irradiation with tensile strength and elongation at break of 21.06 MPa and 1119 %, respectively. Then, the resin was mixed with active diluent, initiator, NH4ClO4, and Al particles to prepare the propellant slurry, and the rheological properties of the slurry were investigated. The results show that the propellant pastes have good flowability at 40 °C and are suitable for 3D printing. Finally, solid propellant and insulation samples with complex structures were effectively generated using UV-curable 3D printing technology, in which the tensile strength and elongation at break of the propellant samples were 0.923 MPa and 63.2 %, respectively. The fabrication of the grains with high precision and performance demonstrated the feasibility of the PUA binder in the 3D-printed propellant.

Dimerization and Crowding in the Binding of Interleukin 8 to Dendritic Glycosaminoglycans as Artificial Proteoglycans.

The interactions of glycosaminoglycans (GAG) with proteins of the extracellular matrix govern and regulate complex physiological functions including cellular growth, immune response, and inflammation. Repetitive presentation of GAG binding motifs, as found in native proteoglycans, might enhance GAG-protein binding through multivalent interactions. Here, we report the chemical synthesis of dendritic GAG oligomers constructed of nonasulfated hyaluronan tetrasaccharides for investigating the binding of the protein chemokine interleukin 8 (IL-8) to artificial, well-defined proteoglycan architectures. Binding of mutant monomeric and native dimerizable IL-8 was investigated by NMR spectroscopy and isothermal titration calorimetry. Dendritic oligomerization of GAG increased the binding affinity of both monomeric and dimeric IL-8. Monomeric IL-8 bound to monomeric and dimeric GAG with KD values of 7.3 and 0.108 μM, respectively. The effect was less pronounced for dimerizable wild-type IL-8, for which GAG dimerization improved the affinity from 34 to 5 nM. Binding of dimeric IL-8 to oligomeric GAG was limited by steric crowding effects, strongly reducing the affinity of subsequent binding events. In conclusion, the strongest effect of GAG oligomerization was the amplified binding of IL-8 monomers, which might concentrate monomeric protein in the extracellular matrix and thus promote protein dimerization under physiological conditions.

Block Synthesis and Step-Growth Polymerization of C-6-Sulfonatomethyl-Containing Sulfated Malto-Oligosaccharides and Their Biological Profiling.

Highly sulfated malto-oligomers, similar to heparin and heparan-sulfate, have good antiviral, antimetastatic, anti-inflammatory and cell growth inhibitory effects. Due to their broad biological activities and simple structure, sulfated malto-oligomer derivatives have a great therapeutic potential, therefore, the development of efficient synthesis methods for their production is of utmost importance. In this work, preparation of α-(1→4)-linked oligoglucosides containing a sulfonatomethyl moiety at position C-6 of each glucose unit was studied by different approaches. Malto-oligomeric sulfonic acid derivatives up to dodecasaccharides were prepared by polymerization using different protecting groups, and the composition of the product mixtures was analyzed by MALDI-MS methods and size-exclusion chromatography. Synthesis of lower oligomers was also accomplished by stepwise and block synthetic methods, and then the oligosaccharide products were persulfated. The antiviral, anti-inflammatory and cell growth inhibitory activity of the fully sulfated malto-oligosaccharide sulfonic acids were determined by in vitro tests. Four tested di- and trisaccharide sulfonic acids effectively inhibited the activation of the TNF-α-mediated inflammatory pathway without showing cytotoxicity.