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Showing papers on "Circular dichroism published in 2021"


Journal ArticleDOI
TL;DR: The DichroWeb as mentioned in this paper tool enables the determination of helix, sheet, and other secondary structure contents of proteins based on their CD spectra, including a range of reference datasets and algorithms for determining the quality of the analyses produced.
Abstract: Circular dichroism (CD) spectroscopy is a widely-used method for characterizing the secondary structures of proteins. The well-established and highly used analysis website, DichroWeb (located at: http://dichroweb.cryst.bbk.ac.uk/html/home.shtml) enables the facile quantitative determination of helix, sheet, and other secondary structure contents of proteins based on their CD spectra. DichroWeb includes a range of reference datasets and algorithms, plus graphical and quantitative methods for determining the quality of the analyses produced. This article describes the current website content, usage and accessibility, as well as the many upgraded features now present in this highly popular tool that was originally created nearly two decades ago.

118 citations


Journal ArticleDOI
TL;DR: In this article, two polyhelicene frameworks consisting, from end-to-end, of 18 and 24 fused benzene rings were synthesized and the latter exhibits the largest electronic circular dichroism in the visible spectrum of any molecule.
Abstract: Here we report the synthesis of two polyhelicene frameworks consisting, from end-to-end, of 18 and 24 fused benzene rings. The latter exhibits the largest electronic circular dichroism in the visible spectrum of any molecule. These shape-persistent helical nanoribbons incorporate multiple helicenes, a class of contorted polycyclic aromatic molecules consisting of ortho-annulated rings. These conjugated, chiral molecules have interesting chemical, biological, and chiroptical properties; however, there are very few helicenes with extraordinary chiroptical response over a broad range of the visible spectrum-a key criterion for applications such as chiral optoelectronics. In this report, we show that coupling the polyhelicene framework with multiple perylene-diimide subunits elicits a significant chiroptic response. Notably, the molar circular dichroism increases faster than the absorptivity of these molecules as their helical axis lengthens. Computational analysis reveals that the greatly amplified circular dichroism arises from exciton-like interactions between the perylene-diimide and the helicene moieties. We predict that even greater chiroptic enhancement will result from further axial elongation of these nanoribbons, which can be readily enabled via the iterative synthetic method presented herein.

78 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed a chiral metasurface (CMS) that exhibits asymmetric transmission of double circularly and linearly polarized waves at the same frequency band.
Abstract: We propose a chiral metasurface (CMS) that exhibits asymmetric transmission (AT) of double circularly and linearly polarized waves at the same frequency band. In order to realize the manipulation of electromagnetic (EM) waves in the whole space, the unit cell of CMS consists of three layers of dielectric substrate and four layers of metal patches. The Z-shaped chiral micro-structure and a grating-like micro-structure are proposed and designed to achieve AT. The simulated results show that the x-polarized wave that is incident along one direction can be transmitted into the right-hand circularly polarized (RHCP) wave and the left-hand circularly polarized (LHCP) wave that is incident along the opposite direction can be reflected as the LHCP wave in the frequency band of 4.69GHz-5.84 GHz. The maximum chirality response can be reflected by AT and circular dichroism (CD) and they can reach up to 0.38 and 0.75, respectively. In addition, we also produced the sample of CMS, and the experimental results are in good agreement with the simulated results.

68 citations


Journal ArticleDOI
TL;DR: In this article, the second harmonic generation circular dichroism (SHG-CD) was developed in bulk single crystals of chiral one-dimensional (1D) [(R/S)-3-aminopiperidine]PbI4.
Abstract: The introduction of chirality into organic-inorganic hybrid perovskites (OIHPs) is expected to achieve excellent photoelectric and nonlinear materials related to circular dichroism. Owing to the existence of asymmetric center and intrinsic chirality in the chiral OIHPs, the different efficiencies of second harmonic generation (SHG) signal occurs when the circularly polarized light (CPL) with different phases passes through the chiral crystal, which is defined as second harmonic generation circular dichroism (SHG-CD). Here, the SHG-CD effect is developed in bulk single crystals of chiral one-dimensional (1D) [(R/S)-3-aminopiperidine]PbI4 . It is the first time that CPL is distinguished using chirality-dependent SHG-CD effect in OIHPs bulk single crystals. Such SHG-CD technology extends the detection range to near infrared region (NIR). In this way, the anisotropy factor (gSHG-CD ) through SHG-CD signal is as high as 0.21.

65 citations


Journal ArticleDOI
TL;DR: In this paper, the first example of luminescent monosubstituted polyacetylenes (mono-PAs) is presented, based on a contracted cis-cisoid polyene backbone.
Abstract: The first example of luminescent monosubstituted polyacetylenes (mono-PAs) is presented, based on a contracted cis-cisoid polyene backbone. It has an excellent circularly polarized luminescence (CPL) performance with a high dissymmetric factor (up to the order of 10-1 ). The luminescence stems from the helical cis-cisoid PA backbone, which is tightly fixed by the strong intramolecular hydrogen bonds, thereby reversing the energy order of excited states and enabling an emissive energy dissipation. CPL switches are facilely achieved by the solvent and temperature through reversible conformational transition. By taking advantages of fast response and high sensitivity, the thin film of mono-PAs could be used as a CPL-based probe for quantitative detection of trifluoroacetic acid with a wider linear dynamic range than those of photoluminescence and circular dichroism. This work opens a new avenue to develop novel smart CPL materials through modulating conformational transition.

63 citations


Journal ArticleDOI
TL;DR: Achiral SOF-1 as an ideal chiroptical platform with adaptive chirality may be applied to determine the enantiopurity of amino acids, develop aqueous CPL materials, and distinguish biological chiral macromolecules via chiralities induction in water.
Abstract: Chiral framework materials have been developed for many applications including chiral recognition, chiral separation, asymmetric catalysis, and chiroptical materials. Herein, we report that an achiral cucurbit[8]uril-based supramolecular organic framework (SOF-1) with the dynamic rotational conformation of tetraphenylethene units can exhibit adaptive chirality to produce M-SOF-1 or P-SOF-1 with mirror-image circular dichroism (CD) with gabs ≈±10-4 and circularly polarized luminescence (CPL) with glum ≈±10-4 induced by L-/D-phenylalanine in water, respectively. The chirality induction in CD (gabs ≈-10-4 ) and CPL (glum ≈-10-4 ) of P-SOF-1 from achiral SOF-1 can be presented by using a small amount of adenosine-5'-triphosphate disodium (ATP) or adenosine-5'-diphosphate disodium (ADP) (only 0.4 equiv) in water. Furthermore, the adaptive chirality of SOF-1 can be used to determine dipeptide sequences (e.g., Phe-Ala and Ala-Phe) and distinguish polypeptides/proteins (e.g., somatostatin and human insulin) with characteristic CD spectra. Therefore, achiral SOF-1 as an ideal chiroptical platform with adaptive chirality may be applied to determine the enantiopurity of amino acids (e.g., L-/D-phenylalanine), develop aqueous CPL materials, and distinguish biological chiral macromolecules (e.g., peptides/proteins) via chirality induction in water.

50 citations


Journal ArticleDOI
06 Apr 2021-ACS Nano
TL;DR: In this article, the authors synthesize 0D chiral copper chloride hybrid, templated by chiral methylbenzylammonium (R/S-MBA)2CuCl4, that display circular dichroism for the ligand-to-metal charge transfer transition with an absorption anisotropy factor (gCD) among the largest reported for chiral metal halide semiconductor hybrid.
Abstract: The emergent properties of chiral organic-inorganic hybrid materials offer opportunities in spin-dependent optoelectronic devices. One of the most promising applications where spin, charge, and light are strongly coupled is circularly polarized light (CPL) detection. However, the performance of state-of-the-art CPL detectors using chiral hybrid metal halide semiconductors is still limited by the low anisotropy factor, poor conductivity, and limited photoresponsivity. Here, we synthesize 0D chiral copper chloride hybrids, templated by chiral methylbenzylammonium (R/S-MBA), i.e., (R-/S-MBA)2CuCl4, that display circular dichroism for the ligand-to-metal charge transfer transition with an absorption anisotropy factor (gCD) among the largest reported for chiral metal halide semiconductor hybrids. To circumvent the poor conductivity of the unpercolated inorganic framework of this chiral absorber, we develop a direct CPL detector that utilizes a heterojunction between the chiral (MBA)2CuCl4 absorber layer and a semiconducting single-walled carbon nanotube (s-SWCNT) transport channel. Our chiral heterostructure shows high photoresponsivity of 452 A/W, a competitive anisotropy factor (gres) of up to 0.21, a current response in microamperes, and low working voltage down to 0.01 V. Our results clearly demonstrate a useful strategy toward high-performance chiral optoelectronic devices, where a nanoscale heterostructure enables direct CPL detection even for highly insulating chiral materials.

49 citations


Journal ArticleDOI
TL;DR: The double π-extended undecabenzohelicene (DHE) as discussed by the authors is a chiral nanographene composed of 65 fused rings and 186 conjugated carbon atoms.
Abstract: This work reports the first double π-extended undecabenzo[7]helicene 1 , which is a large chiral nanographene, composed of 65 fused rings and 186 conjugated carbon atoms. The molecular identity of 1 has been confirmed by single crystal X-ray diffraction. A wine coloured solution of 1 in dichloromethane absorbs light from ultraviolet to the near infrared, featuring an extremely large molar absorption coefficient of 844000 M -1 cm -1 at 573 nm. Optically pure 1 shows a record high electronic circular dichroism intensity in the visible spectral range (|Δe| = 1375 M -1 cm -1 at 430 nm) known for any discrete polycyclic aromatic hydrocarbon. These unusual photophysical properties of 1 contrast sharply with those of a mono-undecabenzo[7]helicene derivative 2 .

43 citations


Journal ArticleDOI
TL;DR: In this article, the effects of chiral molecules on the chiroptical properties of hybrid organic-inorganic perovskites (HOIPs) were investigated, and the HOIP having a Cl-substituted chiral cation exhibits the highest circular dichroism and circular polarized luminescence (CPL) intensities, indicating the existence of the largest rotatory strength.
Abstract: Through the incorporation of various halogen-substituted chiral organic cations, the effects of chiral molecules on the chiroptical properties of hybrid organic-inorganic perovskites (HOIPs) are investigated. Among them, the HOIP having a Cl-substituted chiral cation exhibits the highest circular dichroism (CD) and circular polarized luminescence (CPL) intensities, indicating the existence of the largest rotatory strength, whereas the F-substituted HIOP shows the weakest intensities. The observed modulation can be correlated to the varied magnetic transition dipole of HOIPs, which is sensitive to the d-spacing between inorganic layers and the halogen-halogen interaction between organic cations and the inorganic sheets. These counteracting effects meet the optimal CD and CPL intensity with chlorine substitution, rendering the rotatory strength of HOIPs arranged in the order of (ClMBA)2 PbI4 >(BrMBA)2 PbI4 >(IMBA)2 PbI4 >(MBA)2 PbI4 >(FMBA)2 PbI4 .

42 citations


Journal ArticleDOI
22 Jan 2021
TL;DR: In this article, the origin of chirality and related optical activity of chiral nanomaterials have been revealed unambiguously, including chiral ligand, helix staple motif, asymmetry metal kernel, and chiral arrangement of organic ligands.
Abstract: The emerging chirality in nanomaterials represents one of the most dynamic areas in modern science. Although many novel chiral nanomaterials have been reported, the origin of their chirality and related optical activity have been not unveiled unambiguously. Thanks to the fast development of noble metal cluster chemistry, the structures of many chiral nanoclusters (CNCs) have been precisely determined and their chirality origin has been decoded as four different levels including chiral ligand, helix staple motif, asymmetry metal kernel, and chiral arrangement of organic ligands. Generally, the strong optical activity associated with the electron transitions of the noble metal core is popularly reported among CNCs protected by chiral ligands, following the so-called “outside-in” chirality transfer theory, namely, from organic ligand to metal core. Exceptionally, inherent chiral structures are discerned inside CNCs consisting of achiral ligands, such as the helix staples found in Au38(SR)24 and Au102(SR)44 (SR = thiolate) and the chiral metal kernel existing in Au20(PP3)4Cl4 (PP3 = tris(2-(diphenylphosphino)ethyl) phosphine). These chiral nanostructures induce distinct optical activity and even present reversed chirality transformation in the case of Au38(SR)24 (i.e., from chiral core structure to organic ligand). In the past decade, our group has carried out extensive research work on preparation, enantioseparation, optical activity, and application of chiral inorganic nanostructures. As representatives, enantiopure right-handed and left-handed Au20(PP3)4Cl4 clusters of intrinsic kernel chirality were acquired through an innovative supramolecular self-assembly method and their circular dichroism (CD) feature involving only the metal core was systematically studied; Au3[R/S-Tol-BINAP]3Cl (R/S-Tol-BINAP: R/S-2,2′-bis(di-p-tolylphosphino)-1,1′-binaphthyl) clusters with the smallest metal-atom number among the reported CNCs were designed and synthesized by using the privileged chiral Tol-BINAP ligand, which exhibited not only strongly enhanced CD signal also remarkable circular polarized luminescence (CPL) response as self-assembled into monodispersed nanocubes. In this Account, we aim at reviewing the fast development of CNCs featuring strong chiral attributes and optical activity. We will briefly introduce the preparation methods of CNCs, such as direct synthesis, ligand exchange, and enantioseparation. In the following parts, the commonly used tools for characterizing the chirality of CNCs are summarized, including CD, vibrational circular dichroism (VCD), CPL, single X-ray diffraction, nuclear magnetic resonance (NMR), and theoretical prediction. Then, the optical activity of CNCs will be systematically discussed, especially their CD, VCD, and CPL activity along with their chirality origin. Finally, future strategies for fabricating CNCs possessing strong optical activity as well as potential chirality-related applications will be proposed. We believe that this Account will trigger more research interest to not only study the amazing optical activity of CNCs but also employ them in many fields.

40 citations


Book ChapterDOI
TL;DR: A brief step-by-step guide to record the CD spectra of proteins and their analysis with the BeStSel method, which provides an improved β-structure determination and its performance is more accurate for any of the secondary structure types compared to previous CD spectrum analysis algorithms.
Abstract: Far-UV circular dichroism (CD) spectroscopy is a classical method for the study of the secondary structure of polypeptides in solution. It has been the general view that the α-helix content can be estimated accurately from the CD spectra. However, the technique was less reliable to estimate the β-sheet contents as a consequence of the structural variety of the β-sheets, which is reflected in a large spectral diversity of the CD spectra of proteins containing this secondary structure component. By taking into account the parallel or antiparallel orientation and the twist of the β-sheets, the Beta Structure Selection (BeStSel) method provides an improved β-structure determination and its performance is more accurate for any of the secondary structure types compared to previous CD spectrum analysis algorithms. Moreover, BeStSel provides extra information on the orientation and twist of the β-sheets which is sufficient for the prediction of the protein fold.The advantage of CD spectroscopy is that it is a fast and inexpensive technique with easy data processing which can be used in a wide protein concentration range and under various buffer conditions. It is especially useful when the atomic resolution structure is not available, such as the case of protein aggregates, membrane proteins or natively disordered chains, for studying conformational transitions, testing the effect of the environmental conditions on the protein structure, for verifying the correct fold of recombinant proteins in every scientific fields working on proteins from basic protein science to biotechnology and pharmaceutical industry. Here, we provide a brief step-by-step guide to record the CD spectra of proteins and their analysis with the BeStSel method.

Journal ArticleDOI
TL;DR: In this article, a series of chiral Au13 nanoclusters were synthesized via the direct reduction of achiral dinuclear Au(I) halide complexes ligated by ortho-xylyl-linked bis-N-heterocyclic carbene (NHC) ligands.
Abstract: A series of chiral Au13 nanoclusters were synthesized via the direct reduction of achiral dinuclear Au(I) halide complexes ligated by ortho-xylyl-linked bis-N-heterocyclic carbene (NHC) ligands. A broad range of functional groups are tolerated as wingtip substituents, allowing for the synthesis of a variety of functionalized chiral Au13 nanoclusters. Single crystal X-ray crystallography confirmed the molecular formula to be [Au13(bisNHC)5Cl2]Cl3, with a chiral helical arrangement of the five bidentate NHC ligands around the icosahedral Au13 core. This Au13 nanocluster is highly luminescent, with a quantum yield of 23%. The two enantiomers of the Au13 clusters can be separated by chiral HPLC, and the isolated enantiomers were characterized by circular dichroism spectroscopy. The clusters show remarkable stability, including configurational stability, opening the door to further investigation of the effect of chirality on these clusters.


Journal ArticleDOI
TL;DR: HEWL exhibits a tunable antimicrobial activity against Pseudomonas aeruginosa due to the maximum binding of HEWL with gold nanoparticles, and the combination therapy of protein-gold nanoparticles could prove to be a new approach in medical field in the near future.

Journal ArticleDOI
Song Hu1, Liangyu Hu1, Xuefeng Zhu1, Yuan Wang1, Minghua Liu1 
TL;DR: In this paper, the authors designed symmetric and dissymmetric chiral V-shaped pyrenes to investigate their circular dichroism (CD) and circularly polarized excimer emission (CPEE).
Abstract: Here, we designed symmetric and dissymmetric chiral V-shaped pyrenes by linking achiral pyrenes to trans-1,2-cyclohexane diamine scaffolds with varied spacers to investigate their circular dichroism (CD) and circularly polarized excimer emission (CPEE). In molecular solution, the symmetric V-shaped molecules (P1, P2, P3) displayed spacer-dependent CD and CPEE originating from the intramolecular excimers while the dissymmetric V-shaped B was silent in CD and CPEE. Upon self-assembly, the chiral V-shaped conformation guided a helical hexagonal packing. Notably, P1 self-assembled into delicate superhelices with optimum chiroptical activities and the largest gCD for pyrene derivatives to date. The dissymmetric B formed two distinct hexagonal aggregates as twists and rectangular nanotubes with greatly amplified CPEE. This work demonstrates unprecedented hexagonal superhelices from chiral V-shaped scaffolds and provides a deep insight into the relationship between molecular conformation, supramolecular architectures, and their chiroptical performance.

Journal ArticleDOI
TL;DR: In this article, soy protein isolate (SPI) was noncovalently modified by (-)-epigallocatechin-3-gallate (EGCG), and its foaming, emulsifying, and antioxidant properties were all significantly increased.
Abstract: In the present study, soy protein isolate (SPI) was noncovalently modified by (-)-epigallocatechin-3-gallate (EGCG), and its foaming, emulsifying, and antioxidant properties were all significantly increased. Fluorescence analysis revealed that the fluorescence quenching of SPI by EGCG was static quenching. EGCG mainly changed the folding state of SPI around Trp and Tyr residues, and the binding site was closer to Trp. UV-vis spectra further proved that more hydrophobic residues of SPI were exposed to a hydrophilic microenvironment. Circular dichroism spectra indicated that the contents of ordered structures were transforming into random coils with the reduce of α-helix, β-sheet, and β-turns by 3.8%, 2.0%, and 1.2%, respectively. Meanwhile, the binding stoichiometry of two molecules of EGCG per one molecule of SPI was obtained from isothermal titration calorimetry, and the interaction was a spontaneous endothermic process with a noncovalent complex preferentially formed. According to thermodynamic parameters and molecular docking model, hydrophobic force and hydrogen bonds were considered to be the main interaction forces between SPI and EGCG. Overall, after modification through the high affinity to EGCG, the structure of SPI became looser and exposed more active groups, thus resulting in an improvement of its foaming, emulsifying, and antioxidant properties.

Journal ArticleDOI
TL;DR: In this article, the spiro-linked dibenzo[ a, h ]anthracene fluorophores are arranged in a one-handed twisting direction, through quantitative and chemoselective acid-promoted intramolecular cyclizations of random-coil precursor polymers composed of chiral 1,1'-spirobiindane and achiral bis[2-(4-alkoxyphenyl)ethynyl]phenylene units.
Abstract: We report the unprecedented synthesis of one-handed helical spiro-conjugated ladder polymers with well-defined primary and secondary structures, in which the spiro-linked dibenzo[ a , h ]anthracene fluorophores are arranged in a one-handed twisting direction, through quantitative and chemoselective acid-promoted intramolecular cyclizations of random-coil precursor polymers composed of chiral 1,1'-spirobiindane and achiral bis[2-(4-alkoxyphenyl)ethynyl]phenylene units. Intense circular dichroism (CD) and circularly polarized luminescence (CPL) were observed, whereas the precursor polymers exhibited negligible CD and CPL activities. The introduction of 2,6-dimethyl substituents on the 4-alkoxyphenylethynyl pendants is of key importance for this simple, quantitative, and chemoselective cyclization. This strategy is applicable to the defect-free precise synthesis of other varieties of fully π-conjugated molecules and coplanar ladder polymers that have not been achieved before.

Journal ArticleDOI
TL;DR: In this article, a phenothiazine derivative PtzChol containing nonconjugated chiral cholesterol group was designed and synthesized, and it was found that the introduction of cholesterol produced a positive effect on the production of chiral space group, on mechanoluminescence and room temperature phosphorescence.
Abstract: A phenothiazine derivative PtzChol containing non-conjugated chiral cholesterol group was designed and synthesized. By analyzing the single crystal structure of PtzChol carefully, coupled with the circular dichroism (CD) signals before and after grinding, it was found that the introduction of cholesterol produced a positive effect on the production of chiral space group, on mechanoluminescence (ML) and room temperature phosphorescence (RTP), and throughout the entire light-emitting process, the CD signal could well reflect the changes of molecular arrangement.

Journal ArticleDOI
TL;DR: In this paper, the surface ligands play critical roles in determining the surface properties of metal clusters, and a new insight into modulation of the optical properties of the metal clusters and atomically precise homochiral clusters for specific applications are obtained.
Abstract: Surface ligands play critical roles in determining the surface properties of metal clusters. However, modulating the properties and controlling the surface structure of clusters through surface-capping-agent displacement is challenging. Herein, [Ag14 (SPh(CF3 )2 )12 (PPh3 )4 (DMF)4 ] (Ag14 -DMF; DMF=N,N-dimethylformamide), with weakly coordinated DMF ligands on surface silver sites, was synthesized by a mixed-ligands strategy. Owing to the high surface reactivity of Ag14 -DMF, the surface ligands are labile, easily dissociated or exchanged by other ligands. Based on the enhanced surface reactivity, easy modulation of the optical properties of Ag14 by reversible "on-off" DMF ligation was realized. When chiral amines were introduced to as-prepared products, all eight surface ligands were replaced by amines and the racemic Ag14 clusters were converted to optically pure homochiral Ag14 clusters as evidenced by circular dichroism (CD) activity and single-crystal X-ray diffraction (SCXRD). This work provides a new insight into modulation of the optical properties of metal clusters and atomically precise homochiral clusters for specific applications are obtained.

Journal ArticleDOI
TL;DR: The mechanism by which sodium tripolyphosphate affected the aggregation behavior of ovalbumin-lysozyme complexes was investigated in this paper. And the results showed that the disulfide bond was the most important interaction in the complex.

Journal ArticleDOI
TL;DR: Pepsin is an aspartic proteinase that plays an essential role in controlling many biological processes, therapy, and pharmaceutical research, and catechin hydrate could be considered as an inhibitor with adverse effects on pepsin structure and function.

Journal ArticleDOI
Di Wu, Ran Duan, Lan Tang, Xia Hu, Fang Geng, Qiaomei Sun1, Yin Zhang, Hui Li1 
TL;DR: In this paper, the interaction between lipase and quercetin 3-rhamnoside was studied by fluorescence spectroscopy, enzyme kinetics, and molecular dynamics simulation.

Journal ArticleDOI
Yali Yu1, Yu Guan1, Hedi Wen1, Yan Zhang1, Jingbo Liu1, Ting Zhang1 
TL;DR: The results of intrinsic fluorescence, surface hydrophobicity, and free sulfhydryl groups indicated that the tertiary structure depolymerized, the hydrophobic groups exposed and the protein subunits dissociated.
Abstract: Mild heating (20 °C, 40 °C, 60 °C, and 80 °C) for 1 h assisted pH12 shifting on the structural, physicochemical and functional properties of egg white protein (EWP) were investigated. The results of intrinsic fluorescence, surface hydrophobicity, and free sulfhydryl groups indicated that the tertiary structure depolymerized, the hydrophobic groups exposed and the protein subunits dissociated. Fourier transform infrared spectrophotometer and circular dichroism showed that the content of α-helix decreased, and the content of β-turn increased in the secondary structure of EWP. Moreover, the size and zeta potential of EWP12-80 significantly decreased to 119.17 nm (P

Journal ArticleDOI
TL;DR: In this article, the authors examined the mechanism of binding of β-resorcylic acid (BR) with calf thymus DNA (ctDNA) with the help of various experiments based on spectroscopy and in silico studies.

Journal ArticleDOI
24 Aug 2021-ACS Nano
TL;DR: In this article, a chemical strategy for the synthesis of intrinsically helical plasmonic nanorods (HPNRs) with strong and tailorable PLASmonic circular dichroism (PCD) responses, deriving from the zwitterionic interactions between the -NH3+ and -COO- groups of the cysteine molecules (Cys), was demonstrated.
Abstract: Chiral growth and chirality transfer associated with plasmonic nanostructures have rejuvenated the field of chirality. As the precise regioselective growth of inorganic crystals into chiral shapes at the nanoscale is extremely challenging, "bottom-up" synthesis of intrinsically chiral nanoparticles with structural stability is obviously attractive and important. With the thiolated bimolecular cosurfactants, we demonstrated a chemical strategy for the synthesis of intrinsically helical plasmonic nanorods (HPNRs) with strong and tailorable plasmonic circular dichroism (PCD) responses, deriving from the zwitterionic interactions between the -NH3+ and -COO- groups of the cysteine molecules (Cys). The influence of structural parameters of HPNRs on PCD responses was analyzed systematically by theoretical simulations. Among the different structural parameters, the pitch depth was found to have the greatest impact on the PCD signals, in agreement with the experimental results. Moreover, the obtained HPNRs with the strong, tunable, and stable chiroptical properties were found to be able to induce circularly polarized luminescence of achiral luminophores. Due to the generality of this effect, this chiral plasmonic nanostructure may have great potential for use in the fields of chiral sensors, chiral catalysis, and displays.

Journal ArticleDOI
TL;DR: Docking simulations showed that NDI-5 can effectively bind to the pocket between two G4 units, representing a promising ligand for multimeric G4s.

Journal ArticleDOI
TL;DR: In this paper, a chiral sandwich-shaped multinuclear Ag complex was synthesized and characterized by single crystal X-ray diffraction and NMR studies. But their properties depended on the existence of Pt→Ag dative bonds, and their enantiomers showed circular dichroism and circularly polarized luminescence properties.
Abstract: Multinuclear Ag clusters sandwiched by Pt complex units were synthesized and characterized by single crystal X-ray diffraction and NMR studies. The sandwich-shaped multinuclear Ag complexes showed two different types of fluxional behavior in solution: rapid slippage of Pt complex units on the Ag3 core and a reversible demetalation-metalation reaction by the treatment with Cl anion and Ag ion, respectively. The Ag2 complex obtained by demetalation reaction from the Ag3 complex displayed U to Z isomerization. These multinuclear Ag complexes showed strong photoluminescence whose properties depended on the existence of Pt→Ag dative bonds. The Ag3 complex, identified to be "chiral-at-cluster", was optically resolved by the formation of a diastereomeric salt with a chiral anion. The enantiomers show circular dichroism (CD) and circularly polarized luminescence (CPL) properties which is unprecedented for compounds based on a chiral sandwich structure. Theoretical calculations allow to understand their structural features and photophysical properties.

Journal ArticleDOI
TL;DR: Combined the experimental and theoretical studies, a fundamental understanding of the origin of the chiroptical properties in organic π-liquid was provided and an efficient media for developing soft chiral materials was demonstrated.
Abstract: The solvent-free organic π-liquids have been attracting increasing attentions owing to the inherent optoelectronic properties accompanied by the advantages of non-volatility and high processability. Herein, we reported a series of naphthalene derivatives substituted with chiral branched alkyl chains, which are present as liquids (Nap1-3) or solid (Nap4) at room temperature, depending on the substitution positions. Circular dichroism (CD) and circularly polarized luminescence (CPL) were only observed for enantiomeric Nap2 (2,3-substituted) liquid. It is suggested that the chiral aggregation in the π-liquid leads to the CD signal and the chiral excimer resulting in the CPL performance. When achiral anthracene or pyrene was dissolved in Nap2, the π-liquid could serve as chirality and energy transfer media in which both CD and CPL emerged from the achiral anthracene. A CPL dissymmetry factor (|glum |) of anthracene reached to 5.2×10-2 when dissolved in chiral Nap2 liquid, which is nearly two orders of magnitude higher than that of the pure Nap2 π-liquid.

Journal ArticleDOI
TL;DR: To estimate the toxicity of the RR195 at the protein level, the influences of RR195 on human serum albumin (HSA) were described by molecular modeling, steady-state fluorescence, ultraviolet-visible spectroscopy (UV–Vis), circular dichroism spectroscopic (CD), and Thermal stability (Tm).

Journal ArticleDOI
TL;DR: Molecular dynamics simulation was carried out to assess the stability of the lyso enzyme- NYS complex with RMSD, showing that hydrogen-bonding and van der Waals contributions played an essential role in binding NYS to lysozyme.