Correction to “Structural Analysis of the Terminal Groups in Commercial <i>Hevea</i> Natural Rubber by 2D-NMR with DOSY Filters and Multiple-WET Methods Using Ultrahigh-Field NMR”

Oouchi, Muneki; Ukawa, Jinta; Ishii, Yoshitaka; Maeda, Hitoshi

doi:10.1021/acs.biomac.0c00117

Cited by 2 publications

(3 citation statements)

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“…Furthermore, our assignments were all consistent with homonuclear 2D NMR data based on double-quantum filtered correlation spectroscopy (DQF-COSY) , and total correlation spectroscopy (TOCSY), , heteronuclear 2D NMR data, such as HSQC, HMBC, HSQC with TOCSY (HSQC-TOCSY), and edited HSQC, and HSQC-TOCSY heteronuclear three-dimensional (3D) NMR data using multiple water suppression enhanced through T 1 effects (MWET) ,− (see the Supporting Information). The experimental 13 C chemical shifts were in reasonable agreement with the corresponding values obtained by density functional theory (DFT) calculations using Gaussian 16 (Table ; see Materials and Methods for details), further validating the present structures.…”

Section: Resultssupporting

confidence: 73%

“…HMBC, edited-HSQC, and HSQC-TOCSY experiments with the MWET method were used to measure heteronuclear 2D 1 H/ 13 C NMR spectra; heteronuclear 3D NMR spectra were also recorded using the MWET method with a 900 MHz NMR spectrometer. In the above measurements, strong solvent and main-chain isoprene signals outside the selected bandwidth were suppressed using the MWET method, which overcomes problems such as strong signals masking weak peaks, generation of artifact signals, and reduced sensitivity due to a dynamic range. ,− Furthermore, the band-selective method was used in combination with the heteronuclear 2D NMR experiments to improve the resolution. The band-selective HMBC method ensured the high spectral resolution required for reliable assignments.…”

Section: Methodsmentioning

confidence: 99%

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High-Field Nuclear Magnetic Resonance Studies Reveal New Structural Landscape of Sulfur-Vulcanized Natural Rubber

et al. 2022

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Despite intensive research efforts over the past 3 decades, the structural analysis of sulfur-vulcanized natural rubber (NR) remains challenging owing to the complexity and low population of its sulfur moieties. Herein, solid vulcanized NR samples and NR samples reacted with sulfur and other reactants in an organic solvent were analyzed by solid-state NMR with fast magic-angle spinning and solution NMR, respectively. The present high-field two-dimensional NMR analysis revealed six novel sulfur moieties in these samples, including cyclic sulfides, cyclic di/polysulfides, and crosslinked structures with a vinylidene group. While previous studies reported a variety of sulfur-crosslinked structures in NR, our analysis identified only two dominant types of crosslinked structures that matched those reported previously. Our NMR assignments for the crosslinked structures were inconsistent to a large extent with those presented in the previous studies; thus, in the current work, the crosslinked structures were reassigned using the new data. Based on quantitative NMR analysis, this study also provides the first tangible evidence that cyclic rather than crosslinked sulfides can be the dominant sulfur moieties in vulcanized NR. These results may drastically alter the previously established structural landscape of sulfur-vulcanized NR.

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Section: Resultssupporting

confidence: 73%

Section: Methodsmentioning

confidence: 99%

High-Field Nuclear Magnetic Resonance Studies Reveal New Structural Landscape of Sulfur-Vulcanized Natural Rubber

et al. 2022

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“…The complexity of the composition of jackfruit latex suggests the presence of compounds such as polyphenols, enzymes, proteins, and carotenoids, which are molecules that have different biological activities, including the antioxidant. 26 To verify the absence of these compounds in polyisoprenoid extracts and determine the effectiveness of the extraction process, the antioxidant capacity against ABTS + and DPPH + radicals was evaluated. The EP-1 and EP-6 extracts showed no detectable antiradical activity values for both methods.…”

Section: Antioxidant Capacitymentioning

confidence: 99%

Polyisoprenes obtained from jackfruit latex (Artocarpus heterophyllus L.): Extraction and characterization

Ramos‐Martínez

González-Cruz

Calderón‐Santoyo

et al. 2022

J of Applied Polymer Sci

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Jackfruit latex is a residue from the agricultural production of this fruit, which does not have an application in the food or pharmaceutical industry. The objectives of the study were to (1) extract the polyisoprenes from jackfruit latex using the surfactant sodium lauryl sulfate, and (2) characterize their physicochemical and techno-functional properties. The chemical composition, foaming and emulsifying capacity, and thermal behavior. According to the proximal chemical analysis of the extracts, the major content were lipophilic compounds (89%), including polyisoprenes. Regarding the emulsifying properties, the concentrates extracts showed intermediate values for the emulsifying activity index (32-59 m 2 /g) and stability times from 15 to 95 min. The thermal analysis showed endothermic events (50-65 C) associated with the melting of the concentrate, as well as exothermic events related to the crystallization of the polyisoprenes. The FTIR spectra indicates the presence of the polyisoprenes in the extracts, the stretching of the C═C bonds in 1704 at 1712 cm À1 are characteristic of cis-1,4 polyisoprene bonds, and at 980 cm À1 the C H bending. The physicochemical and techno-functional properties of polyisoprene extracts indicate that they could be used in emulsions or electrohydrodynamic encapsulation processes.

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Correction to “Structural Analysis of the Terminal Groups in Commercial Hevea Natural Rubber by 2D-NMR with DOSY Filters and Multiple-WET Methods Using Ultrahigh-Field NMR”

Cited by 2 publications

References 0 publications

High-Field Nuclear Magnetic Resonance Studies Reveal New Structural Landscape of Sulfur-Vulcanized Natural Rubber

High-Field Nuclear Magnetic Resonance Studies Reveal New Structural Landscape of Sulfur-Vulcanized Natural Rubber

Polyisoprenes obtained from jackfruit latex (Artocarpus heterophyllus L.): Extraction and characterization

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