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A through-bond energy transfer-based ratiometric fluorescent pH probe: For extreme acidity and extreme alkaline detection with large emission shifts
摘要： A ratiometric fluorescence pH probe 1 based on through-bond energy transfer (TBET) with a 2-(2-hydroxyphenyl)benzoxazole (HBO) as donor and a Rhodamine derivative as acceptor is developed through simple condensation reaction. The probe exhibits a ratiometric fluorescence emission (I593/I422) characteristics and linear response to extreme acidity range of 5.00-2.88, and a ratiometric fluorescence emission (I555/I422) characteristics and linear response to extreme alkaline range of 10.00-13.78, respectively. Moreover, 1 possesses highly selective response to pH over metal ions, good reversibility and excellent photostability. Probe 1 is cellpermeable and can distinguish near pH 5.55 fluctuations in Hela cells. Furthermore, 1 can be immobilized on a test paper, which shows a rapid and reversible colorimetric response to HCl/NH3 vapor by the naked-eye.
关键词： ratiometric fluorescent response,pH sensing,large emission shifts,through-bond energy transfer,fluorescent probe
更新于2025-11-21 11:24:58
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Effect of Unsymmetrically Branched Alkyl Chains on the Electrochemical Band Gap and Thermal Stability of the PCDTBT
摘要： This work introduces a modified poly[N-9’-heptadecanyl-2,7-carbazole-alt-5,5-(4’,7’-di-2-thienyl-2’,1’,3’-benzothiadiazole)] (PCDTBT) with the unsymmetrically branched N-alkyl chain, which name as poly[N-9’-(2-hexyldecyl)-2,7-carbazole-alt-5,5-(4’,7’-di-2-thienyl-2’,1’,3’-benzothiadiazole)] (P1). The synthesis of P1 involves dimerization, cyclization, tosylation, N-alkylation, bromination, Stille’s and Suzuki’s coupling reactions. Suitable analysis techniques have used to study the chemical, physical, electrochemical, optical, and thermal properties of P1. The analysis results show that P1 possesses higher HOMO and LUMO energy levels than the previously reported PCDTBT, which have been narrowing the electrochemical band gap down to 1.58 eV. However, the P1 experiences 5% thermal degradation at 280 °C, which is relatively less favourable than the PCDTBT. Hence, the replacement of the symmetrically branched alkyl chains of PCDTBT with unsymmetrically branched alkyl chains results in both improvement and draw-back on the characteristics of the polymer.
关键词： bond energy,Alkylation,cyclic voltammetry,electrochemistry,polymerization
更新于2025-11-19 16:56:35
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Correction: Boosted visible light photodegradation activity of boron doped rGO/g-C <sub/>3</sub> N <sub/>4</sub> nanocomposites: the role of C–O–C bonds
摘要： A series of two-component co-crystals driven by I···N interactions based on the bipyridine (BIPY) chromophore with one among three different co-former building blocks, iodopentafluorobenzene (IPFB), 1,4-diiodotetrafluorobenzene (DITFB) and 1,3,5-trifluoro-2,4,6-triiodobenzene (IFB), were prepared and analysed via infrared spectroscopy and single-crystal X-ray diffraction. By comparing the I···N distances in the co-crystal structures, we found that the higher the –F ratio in the building blocks the closer the contact of the I···N bond, enhancing the intermolecular interactions in these co-crystals as well. That is, the positive electrostatic potential on the iodine atom(s) in the co-formers was enhanced by the presence of strong electron-withdrawing groups. The distinct spectroscopic behaviours (fluorescence and Raman spectra) among the two-component BIPY co-crystal systems in response to hydrostatic pressure were also investigated. Interestingly, the fluorescence of BIPY–DITFB presented intriguing abnormal evolution from dark to bright, suggesting a new charge transfer state due to the decreased intermolecular distance and the enhanced I···N interactions. Theoretical simulations by Materials Studio also showed the shortened I···N distance and the increased angle of C–I···N, evidencing the enhanced I···N interactions. In contrast, BIPY–IFB showed only slightly enhanced fluorescence intensity at 550 nm consistent with BIPY–DITFB. Once the pressure was relieved, both the Raman and fluorescence spectra for BIPY co-crystal systems entirely self-recovered. Remarkable emission enhancement in a solid-state co-crystal has been rarely reported in previous publications and in fact, this study paves a unique way for designing and developing novel stimuli-responsive photo-functional materials.
关键词： co-crystals,piezochromic materials,halogen bond,intermolecular charge transfer,pressure-induced emission enhancement
更新于2025-11-14 15:14:40
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Theoretical elaboration about the excited state dynamical behaviors for a novel fluorescent sensor
摘要： Using the density functional theory (DFT) and time‐dependent density functional theory (TDDFT) methods, we theoretically explore a novel fluorescent sensor molecule (abbreviated as “2”) (Sensors Actuat B‐Chem. 2018, 263, 585). Because of its symmetry, three stable structures can be located, ie, 2‐enol, 2‐SPT, and 2‐DPT forms in both S0 and S1 states. Via comparing the bond lengths and bond angles involved in the hydrogen bonding moieties, we find the dual intramolecular hydrogen bonds should be strengthened in the S1 state. And based on infrared (IR) vibrational simulations, we further confirm the strengthening dual hydrogen bonds. Upon the photo‐excitation process, the charge redistribution via frontier molecular orbitals (MOs) reveals the tendency of excited state intramolecular proton transfer (ESIPT) reaction. In addition, the constructed S0‐state and S1‐state potential energy curves demonstrate that the excited state single proton transfer (ESSPT) should be the most supported one from 2‐enol to 2‐SPT form. In view of the S1‐state stable 2‐SPT and 2‐DPT structures as well as the fluorescence peaks of them, we can further confirm the ESSPT mechanism for 2 chemosensor. This work not only clarifies the excited state behaviors of 2 system but also successfully explain the previous experimental phenomenon.
关键词： charge redistribution,ESIPT,potential energy curves,intramolecular hydrogen bond
更新于2025-09-23 15:23:52
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Mechanism Behind the Easy Exfoliation of Ga <sub/>2</sub> O <sub/>3</sub> Ultra-Thin Film Along (100) Surface
摘要： The transparent wide band gap semiconductor β-Ga2O3 has gained wide attention due to its suitability to a wide range of applications. Despite not being a van der Waals material and having highly strong ionic bonding, the material can be mechanically cleaved and exfoliated easily along favorable surfaces to make ultra-thin layers and used in device fabrications. One of the interesting properties of this material is that thin layers preserve the pristine bulk-like electronic properties, which makes it even more promising for applications in power devices. However, very little is known about the mechanism why such ultra-thin film or even single bilayer exfoliation is favorable from the bulk. In this letter, we have explained the mechanism of such phenomenon by detailed analyses of different types of Ga–O bonding character. The protocol of methodology used and developed in this study can be utilized in general to understand bond breaking and forming of other complex materials as well. This understanding will give us a better control to fabricate thin film 2D devices.
关键词： density functional theory,bond energy,computational physics,2D Ga2O3,easy exfoliation,surface energy
更新于2025-09-23 15:23:52
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Shedding light on the electronic structure of [Ru(η6-C16H16)(NH3)3]2+ complex: a computational insight
摘要： Ruthenophanes have been recognized as potential candidates to the design of electrically conducting polymers, particularly due to their electrochemical, structural, and spectroscopic properties. The comprehension and rationalization of the metal–ligand interaction is fundamental to pave the way for future applications as the design of new conducting materials. For that reason, this investigation sheds light on the electronic details behind the cation–π interactions present in ruthenophanes by using [Ru(η6-C16H16)(NH3)3]2+ as a model. Zeroth-order symmetry-adapted perturbation theory (SAPT0) shows the interaction Ru(II)–[2.2]paracyclophane with a predominant covalent character. However, the hapticity analysis of [2.2]paracyclophane shows only two predominantly covalent Ru–C bonds, as highlighted by the total energy density, H(r), in the bond critical point (BCP) obtained from quantum theory of atoms in molecules (QTAIM) method, and by second-order stabilization energy, (cid:4)E(2), related to the processes: π C–C → dσ or dπ Ru, achieved in the natural bond orbital (NBO) method. The other two Ru–C chemical bonds show a largely electrostatic character, as can be visualized from the delocalization index, DI, between the electron basins in the electron localization function (ELF) method. Remarkably, the interacting quantum atoms (IQA) method showed practically the same value of the total interaction energy, EAB int , between Ru and these C atoms and, then, corroborates the hapticity four of the ligand: [2.2]paracyclophane. Source function distribution presents a correlation with the electronic interactions between different groups in [Ru(η6-C16H16)(NH3)3]2+.
关键词： Ru-C chemical bond,Cation–π interaction,ELF,IQA,SAPT,Hapticity
更新于2025-09-23 15:23:52
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Reporting of light irradiation conditions in 300 laboratory studies of resin-composites
摘要： Objective. To evaluate how the light delivered to resin-composites was described in recent articles. Method. PubMed was searched for 300 articles published between January 2017 and May 2018 with keywords relating to photocuring of dental materials. The articles examined a wide range of resin-composite properties and performance. For each article, the information provided about the light curing unit (LCU), the light curing conditions and the characteristics and quantity of the light used in the study were recorded. Specifically, the type of LCU used; the irradiance; how the irradiance was measured; the exposure times; whether the light energy (radiant exposure) received by the specimen was determined, or if only the light output at the LCU tip was measured; whether the distance between the tip of the LCU and the specimen was reported; and whether the emission spectrum from the LCU was reported. Where possible, the resin manufacturer’s minimum energy requirement (MER: the product of the recommended minimum exposure time and irradiance) was compared to the radiant exposure delivered to the specimen. Results. Of the 300 articles examined, 217 were published in 2017 and 83 in 2018. Of these articles, 130 (43%) were found in open access journals, and 170 (57%) were in subscription-based journals. The name of the LCU used was not provided in 31 articles, 14 articles did not provide the exposure time, and 227 articles did not report the distance to the specimen. An irradiance value was reported in 231 articles, but this was the irradiance received by the specimen in only 48 instances. The emission spectrum from the LCU was reported in 15 articles. There was a large range in the radiant exposures from below 10 J/cm2 to greater than 100 J/cm2. Significance. The majority of articles from 2017 and early 2018 did not include sufficient description of the characteristics and quantity of the light received by the resin-composite specimens to allow the study to be replicated. It is recommended that future articles should report: (1) the identity of the LCU used; (2) the radiant exposure received by the specimen (J/cm2); and (3) appropriate reference to the emission spectrum from the LCU.
关键词： Research reproducibility and replicability,Bond strength,Resins,Light curing,Bulk fill,Light measurement
更新于2025-09-23 15:23:52
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Effect of phototherapy on dentin bond strength and microleakage when bonded to resin with different conditioning regimes
摘要： Aim To assess the efficacy of phototherapy on bond strength and microleakage of bulk fill composites in comparison to conventional dentin surface treatments. Materials and Methods Ninety human third molars were divided into 3 groups (n=30 each) according to surface conditioning treatment. Group 1 (Etch and Bond) EB, group 2 was treated with Er,Cr: YSGG (ECL) and group 3 was treated with a diode laser (DL). Based on the type of bulk fill resin composite, samples were divided into six sub-groups. In sub-group 1, 2 and 3 (n=15) build-up was done using ZirconCore (ZC) and these subgroups were named as EB-ZC, ECL-ZC and DL-ZC. In subgroup 4,5,6 (n=15) MulticCore Flow (MC) was used for core build-up and these subgroups were named as EB-MC, ECL-MC, DL-MC. For shear bond strength (SBS) all the samples were exposed to loads using a universal testing machine. Five samples each from all subgroups were immersed in methylene blue dye for 24hours prior to microleakage testing. Data were assessed using analysis of variance and Tukey multiple comparisons test. Results: Among all the groups the lowest bond strength was achieved in DL-ZC [10.45(0.459)]. Similarly, the highest bond strength was attained in EB-MC[17.84(0.925)]. The highest microleakage scores amongst different group was exhibited in DL-ZC [82.45(39.459)] whereas, the lowest microleakage scores were displayed in EB-MC [31.21(15.92)]. Conclusion: Phototherapy in the form of Er,Cr:YSGG laser showed comparable adhesive bond outcomes to conventional etch and bond dentin conditioning techniques. Moreover, Multicore bulk fill material showed better bond strength and microleakage scores than zirconium particle infiltrated bulk fill composite in the presence of dentin phototherapy.
关键词： dentine,bond strength,Cr: YSGG,microleakage,Er,bulk fill composite
更新于2025-09-23 15:23:52
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Developing cysteamine-modified SERS substrate for detection of acidic pigment with weak surface affinity
摘要： In this paper, we developed cysteamine-modified surface-enhanced Raman scattering (SERS) substrate for detecting detect trace amount of acidic pigment that shows weak affinity with gold nanoparticles (Au NPs). To realize sensitive and reproducible detection of pigment with weak affinity, the SERS substrate was prepared by attaching cysteamine (CA) to the Au NPs, the acidic pigment molecule could rapidly reached to the surface of Au NPs because of the formation of multi-hydrogen-bond and electrostatic interaction between the pigment and CA molecule. The proposed method allowed us to detect five kinds of acidic pigment with a limit of 1.0 ppm, which is below the strictest safety limit. Compared with the previous methods, the advantages of the present substrate were its simple substrate preparation, high reproducibility and good universality. Furthermore, the reliable and enough accurate results had been obtained by using of the proposed substrates in the assay of trace pigment in real samples.
关键词： surface-enhanced Raman scattering,hydrogen bond interaction,cysteamine-modified,acidic pigment,weak affinity
更新于2025-09-23 15:23:52
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Artificial Photosynthesis for Carbon Dioxide Reduction and Conversion
摘要： In recent years, solar fuel or chemical production based on the photoreduction or fixation of CO2, the so-called “artificial photosynthesis” has received considerable attention. Thus, the development of an effective catalyst for the conversion of CO2 to useful organic molecules is desirable. Biocatalysts for CO2 reduction and conversion are useful catalyst for the artificial photosynthesis system. In this review, two types of artificial photosynthesis systems for CO2 reduction and conversion consisting of the visible-light sensitizer and biocatalyst are introduced. One is the artificial photosynthesis with visible-light sensitizer and biocatalyst for CO2 photoreduction to formic acid or methanol. The other one is the artificial photosynthesis with visible-light sensitizer, and novel electron carrier molecule and biocatalyst for the carbon-carbon bond formation from CO2 as a feedstock.
关键词： carbon-carbon bond formation,artificial photosynthesis,biocatalyst,CO2 reduction and conversion
更新于2025-09-23 15:23:52