Polar Solutes Research Articles

Alkali cation-π interactions in aqueous systems, modulating supramolecular stereoisomerism of nanoscopic metal-organic capsules

Contrary to common chemical intuition, cation-π interactions can persist in polar, aqueous reaction solutions, rather than in dry non-coordinative solvent systems. This account highlights how alkali ion-π interactions impart distinctive structure-influencing supramolecular forces that can be exploited in the preparation of nanoscopic metal-organic capsules. The incorporation of alkali ions from polar solutions into molecular pockets promotes the assembly of otherwise inaccessible capsular entities whose structures are distinctive to those of common polyoxovanadate clusters in which {V=O} moieties usually point radially to the outside, shielding the molecular entities. The applied concept is exemplified by homologous {V20} and {V30} cages, composed of inverted, hemispherical {V5O9} units. The number and geometrical organization of these {V5O9} sub-units in these cages are associated with prevailing cation-π\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pi$$\\end{document} interactions and competing steric effects. The stereoisomers of these resulting nano-sized objects are comparable to Alfred Werner-type structural isomers of simple mononuclear complexes in-line with fundamental coordination chemistry principles.

Activity coefficients of 3-amino-1-propanol and 2-amino-1-propanol in aqueous solutions from surface tension data

Surface tension of 3-amino-1-propanol and (RS)-2-Amino-1-propanol in aqueous solution were measured in the temperature range from 293.15 to 308.15 K at intervals of 5 K over the whole concentration range. The concentration dependence of surface tension for both amino alcohols aqueous solution shows a similar behavior to that observed for other polar solutes in water. The surface tension data of 3-amino-1-propanol and 2-amino-1-propanol at the selected temperatures were accurately described using the integral Gibbs adsorption equation, the virial equation, and the Langmuir-Gibbs equation of state. The activity coefficients γ for both solutes were determined using the virial equation and found to be unitary within the experimental uncertainty, which was confirmed by the accurate representation of the experimental data by the Langmuir Gibbs Equation of State (LGSEOS). The standard adsorption energy calculated for both solutes from the fitting parameters of LGSEOS to the experimental data indicates that (RS)-2-amino-1-propanol has a higher hydrophobic character and a greater tendency to migrate to the surface than 3-amino-1-propanol as shown by the more negative ΔGads0 values for this solute than for 3-amino-1-propanol.

Biocompatibility analysis of titanium bone wedges coated by antibacterial ceramic-polymer layer

This paper presents the surface treatment results of titanium, veterinary bone wedges. The functional coating is composed of a porous oxide layer (formed by a plasma electrolytic oxidation process) and a polymer poly(sebacic anhydride) (PSBA) layer loaded with amoxicillin (formed by dip coatings). The coatings were porous and composed of Ca (4.16%-6.54%) and P (7.64%-9.89% determined by scanning electron microscopy with EDX) in the upper part of the implant. The titanium bone wedges were hydrophilic (54° water contact angle) and rough (surface area (Sa):1.16 μm) The surface tension determined using diiodomethane was 68.6 ± 2.0° for the anodized implant and was similar for hybrid coatings: 60.7 ± 2.2°. 12.87 ± 0.91 µg/mL of amoxicillin was released from the implants during the first 30 min after immersion in the phosphate-buffered saline (PBS) solution. This concentration was enough to inhibit the Staphylococcus aureus ATCC 25923, and Staphylococcus epidermidis ATCC12228 growth. The obtained inhibition zones were between 27.3 ± 2.1 mm–30.7 ± 0.6 mm when implant extract after 1 h or 4 h immersion in PBS was collected. Various implant biocompatibility analyses were performed under in vivo conditions, including pyrogen test (3 rabbits), intracutaneous reactivity (3 rabbits, 5 places by side), acute systemic toxicity (20 house mice), and local lymph node assay (LLNA) (20 house mice). The extracts from implants were collected in polar and non-polar solutions, and the tests were conducted according to ISO 10993 standards. The results from the in vivo tests showed, that the implant’s extracts are not toxic (mass body change below 5%), not sensitizing (SI < 1.6), and do not show the pyrogen effect (changes in the temperature 0.15ºC). The biocompatibility tests were performed in a certificated laboratory with a good laboratory practice certificate after all the necessary permissions.

Harnessing Polar Interactions Tunes the Stability of Ultrathin Polymer Solution Films.

The stability of ultrathin (<100 nm) polymer films is essential in applications like protective coatings. On the contrary, their instability may actually be desirable for the emergence of self-assembled nanoscale patterns utilized in the fabrication of functional devices. Polymer solution films exhibit two distinct kinds of instabilities, viz., dewetting (long-wave) and decomposition (short-wave). Dewetting refers to the rupture of the continuous film to form isolated domains, while decomposition leads to phase separation within the polymer solution. The focus of this work is on leveraging polar interactions between the solute and solvent molecules to tune the stability of the film. A gradient dynamics-based thin film model is developed to investigate pattern formation in a thin polar polymer solution film. The Flory-Huggins theory is suitably modified by introducing a polar interaction parameter that depends upon the concentration of the polymer and the dipole moments of monomer (μ1) and solvent molecules (μ0). A linear stability analysis is performed to determine the characteristic length scale and growth rate of the instabilities. It is shown that the range of concentration space for the occurrence of the decomposition mode is directly affected by the Flory interaction parameter (χ0), μ0, and μ1, thereby serving as control parameters to tune the width of the concentration range. It is further shown that ignoring polar interactions may lead to incorrect predictions of the instability mode, including a complete loss of the decomposition mode. In addition, the long-wave dewetting length scale is found to decrease due to bulk dipolar interactions at higher polymer concentrations. Finally, numerical simulations are carried out to track the nonlinear evolution of the interface and concentration field for both the decomposition and dewetting modes of instability.

Source parameters and aftershock pattern of the October 7, 2021, M5.9 Harnai earthquake, Pakistan

On October 7, 2021, a magnitude 5.9 earthquake struck the Harnai (Baluchistan) region of Pakistan, causing several fatalities and injuries within the epicentral area. First-order tectonic deformation in this region is caused by the convergence of the Indian Plate with respect to the Eurasian Plate. The Katwaz Block hinders the motion of the Indian Plate, resulting in the formation of strike-slip faults. In this study, the P-wave first-motion polarity technique was used to determine the mainshock faulting style. Cyclic scanning of the polarity solutions was applied to determine the most suitable focal mechanism solution among the available solutions generated by the FOCMEC (focal mechanism) software. The nodal planes correspond to different faulting styles (i.e., thrust and strike-slip faulting). A nodal plane oriented in the NW-SE direction corresponded to a strike-slip mechanism, which was considered to be the fault plane. Tectonically, this earthquake was associated with the Harnai-Karahi strike-slip fault zone owing to the fault strike and direction of slip. The apparent stress drop, fault length, and moment magnitude of the Harnai earthquake were 35.4 bar, 6.1 km, and 5.9, respectively. A lower b-value for the Gutenberg-Richter law was observed prior to the earthquake. Higher α- than b-values (α >b) indicate that this earthquake was governed by large events as opposed to small-magnitude events. The Harnai sequence had a decay exponent close to unity, lasted for 145 days, and produced few aftershocks. The study will help the future hazard mitigation in the region.

Ring Rearrangement Reactions of 4-Alkenylisocoumarins and Photophysical Evaluation of Multi-Substituted Anthracene Products.

Herein we report that readily available 4-alkenylisocoumarins can be regarded as potent dienolate equivalents. For example, lactol silyl ethers derived from 4-alkenylisocoumarins were selectively converted to the corresponding benzo-homophthalates through a fluoride-induced ring opening step that was followed by a ring closure through a vinylogous intramolecular aldol condensation. Likewise, nucleophilic activation of 4-alkenylisocoumarins directly yields diversely poly-substituted naphthalenes and anthracenes without formation of any regioisomer. Photophysical evaluation of a set of thus obtained 1,3-di- and 1,3,4-trisubstituted anthracenes reveals their distinct intramolecular charge transfer (ICT) character during light absorption in polar solutions and excimer emission from the solid state when a face-to-face π-stacked molecular assembly is present in the crystal packing.

Nanoclustering in non-ideal ethanol/heptane solutions alters solvation dynamics.

Alcohol/alkane solutions widely used in chemical synthesis and as transportation fuels are highly non-ideal due to the nanoscale clustering of the amphiphilic alcohol molecules within the nonpolar alkanes. Besides impacting reactivity, such as combustion, non-ideal solutions are likely to exhibit unusual solvation dynamics on ultrafast time scales arising from the structurally heterogeneous nature of molecular-scale association. Using a convenient transition metal carbonyl vibrational probe [(C5H5)Mn(CO)3, CMT], linear absorption and nonlinear two-dimensional infrared (2D-IR) spectroscopy reveal composition-dependent solvation dynamics as reported by the frequency fluctuation correlation function in a series of ethanol/heptane solutions. Slow spectral diffusion with dilute ethanol indicates preferential solvation of the polar solute by the alcohol with a mechanism largely dominated by solvent exchange. Comparison with an ethanol/acetonitrile solution series yields no substantial preferential solvation or solvent exchange signatures in the linear or 2D-IR spectra. In ethanol/heptane solutions, increasing the ethanol concentration speeds up the solvation dynamics, which is largely consistent with a model that includes solvent exchange and single-solvent spectral diffusion. Detailed analysis of the deviation from the experimental time constants from the model's optimal parameters yields a remarkable resemblance of the concentration-weighted Kirkwood-Buff integrals for ethanol/heptane solutions. This trend indicates that solution non-ideality alters the spectral diffusion dynamics of the probe solute. Given that nanoscale clustering drives the non-ideality, these experiments reveal a dynamical consequence of nanoscale heterogeneity on the ultrafast dynamics of the solution. Refined understanding of the structural and dynamical aspects of mixed solvents will be necessary for predictive solution strategies in chemistry.

Just passing through: Deploying aquaporins in microbial cell factories.

As microbial membranes are naturally impermeable to even the smallest biomolecules, transporter proteins are physiologically essential for normal cell functioning. This makes transporters a key target area for engineering enhanced cell factories. As part of the wider cellular transportome, aquaporins (AQPs) are responsible for transporting small polar solutes, encompassing many compounds which are of great interest for industrial biotechnology, including cell feedstocks, numerous commercially relevant polyols and even weak organic acids. In this review, examples of cell factory engineering by targeting AQPs are presented. These AQP modifications aid in redirecting carbon fluxes and boosting bioconversions either by enhanced feedstock uptake, improved intermediate retention, increasing product export into the media or superior cell viability against stressors with applications in both bacterial and yeast production platforms. Additionally, the future potential for AQP deployment and targeting is discussed, showcasing hurdles and considerations of this strategy as well as recent advances and future directions in the field. By leveraging the natural diversity of AQPs and breakthroughs in channel protein engineering, these transporters are poised to be promising tools capable of enhancing a wide variety of biotechnological processes.

Effect of porosity and temperature on viscosity and diffusivity of benzene liquid containing nanobubble with molecular dynamics

Introduction of nanobubble (NB) into liquid can significantly affect the transport properties such as viscosity and diffusivity, being important in the design and optimization of many liquid-related industrial processes. The present paper reports the atomistic insights into influence of porosity (volume fraction of NBs in solution) and temperature on viscosity and self-diffusion coefficient in benzene liquid containing NBs by using molecular dynamics (MD) simulation with the COMPASS force field. We make molecular modeling of NB-containing benzene liquid using the cubic box with porosities increasing from 0 to 24.6% and conduct a series of MD simulations as increasing temperature from 298 to 343 K. Our simulations reveal that as increasing the porosity the viscosity decreases according to the cubic polynomial while the self-diffusion coefficient increases rapidly. When compared with high polar NB aqueous solutions, although the changing tendencies of transport properties are similar, the changing degrees in benzene liquid are clearly higher, indicating that NB creation has a stronger influence on transport properties of non-polar benzene liquid due to the weaker intermolecular interaction. Meanwhile, as increasing temperature, the viscosity decrease while the self-coefficient increases, both according to the Arrhenius equation. Such temperature dependence is similar to aqueous solution, meaning that temperature affects the transport properties of polar and non-polar liquids alike. This work will contribute to developing NB utilization to practical applications.

Experimental and Theoretical Rotational Diffusion Studies of 7DM4M1M1,8, N-2(1H)-one and 7A4T2H1B-2-one in Series of Alcohol Solvents: Stoke's-Einstein-Debye and Alavi-Waldeck Models.

Rotational diffusion studies of two solutes 7-(dimethylamino)-4-methoxy-1-methyl-1,8-naphthyridin-2(1H)-one (7DM4M1M1,8, N-2(1H)-one) and 7-amino-4-(trifluoromethyl)-2H-1-benzopyran-2-one (7A4T2H1B-2-one) having equal volumes but different chemical natures are studied in series of alcohol solvents at 303K using steady-state methods. HOMO-LUMO, Electron density, Molecular electrostatic potential (MEP), etc., are obtained from computational calculations using Gaussian 09 software. Rotational reorientation times of 7DM4M1M1,8, N-2(1H)-one solute molecule is found to be less than 7A4T2H1B-2-one solute molecule indicates it rotates slowly in chosen solvents. Stoke's-Einstein-Debye (SED) model with stick boundary conditions for the 7A4T2H1B-2-one solute molecule is modeled to describe mechanical friction. Polar solutes along with mechanical friction also experience dielectric friction. Both these frictions being non-separable, the Alavi-Waldeck (AW) model is studied for dielectric friction contribution to the total friction solute experiences in solvents. AW model effectively explains the observed dielectric friction in alcohol solvents.

A guide to precise measurements of isotope abundance by ESI-Orbitrap MS.

Stable isotopes of carbon, hydrogen, nitrogen, oxygen and sulfur are widespread in nature. Nevertheless, their relative abundance is not the same everywhere. This is due to kinetic isotope effects in enzymes and other physical principles such as equilibrium thermodynamics. Variations in isotope ratios offer unique insights into environmental pollution, trophic relationships in ecology, metabolic disorders and Earth history including climate history. Although classical isotope ratio mass spectrometry (IRMS) techniques still struggle to access intramolecular information like site-specific isotope abundance, electrospray ionization-Orbitrap mass spectrometry can be used to achieve precise and accurate intramolecular quantification of isotopically substituted molecules ('isotopocules'). This protocol describes two procedures. In the first one, we provide a step-by-step beginner's guide for performing multi-elemental, intramolecular and site-specific stable isotope analysis in unlabeled polar solutes by direct infusion. Using a widely available calibration solution, isotopocules of trifluoroacetic acid and immonium ions from the model peptide MRFA are quantified. In the second approach, nitrate is used as a simple model for a flow injection routine that enables access to a diverse range of naturally occurring isotopic signatures in inorganic oxyanions. Each procedure takes 2-3 h to complete and requires expertise only in general mass spectrometry. The workflows use optimized Orbitrap IRMS data-extraction and -processing software and are transferable to various analytes amenable to soft ionization, including metabolites, peptides, drugs and environmental pollutants. Optimized mass spectrometry systems will enable intramolecular isotope research in many areas of biology.

Effect of Tetramethylurea (TMU) on Polysulfone Membrane Performance for Atrazine-containing Wastewater Treatment

Tetramethylurea (TMU) is a good solvent for organic substances and has received little attention as compared to other solvents. The TMU is a polar solution and is one of the molecules with an amphiphilic character. In the present work, an attempt has been made to use TMU as an additive in the preparation of nanofiltration membranes to improve the hydrophilicity of the membrane. The polysulfone membrane has been modified by incorporating different concentrations of TMU (0, 0.5, and 1 wt.%) in order to check the rejection of atrazine in water. This study aim is to optimize the conditions to enhance the flux and the rejection of atrazine. It was observed that the rejection of atrazine was enhanced when feed pH changed to acidic and with increasing the evaporation time. The prepared membranes were subjected to different analyses, such as contact angle measurement, FTIR, porosity, and mean pore size. The effect of the coagulation bath, evaporation time, and pH on the atrazine rejection was also studied. Membrane with 0.5 wt.% TMU shows maximum rejection of atrazine at the operating pressure of 15 kgf/cm2.

Chemical Constituents, Hypolipidemic, and Hypoglycemic Activities of Edgeworthia gardneri Flowers.

The flowers of Edgeworthia gardneri are used as herbal tea and medicine to treat various metabolic diseases including hyperglycemia, hypertension, and hyperlipidemia. This paper investigate the chemical constituents and biological activities of ethanolic extract and its different fractions from E. gardneri flowers. Firstly, the E. gardneri flowers was extracted by ethanol-aqueous solution to obtain crude extract (CE), which was subsequently fractionated by different polar organic solution to yield precipitated crystal (PC), dichloromethane (DCF), ethyl acetate (EAF), n-butanol (n-BuF), and residue water (RWF) fractions. UHPLC-ESI-HRMS/MS analysis resulted in the identification of 25 compounds, and the main compounds were flavonoids and coumarins. The precipitated crystal fraction showed the highest phenolic and flavonoid contents with 344.4 ± 3.38mg GAE/g extract and 305.86 ± 0.87mg RE/g extract. The EAF had the strongest antioxidant capacity and inhibitory effect on α-glucosidase and pancreatic lipase with IC50 values of 126.459 ± 7.82 and 23.16 ± 0.79 µg/mL. Besides, both PC and EAF significantly regulated the glucose and lipid metabolism disorders by increasing glucose consumption and reducing TG levels in HepG2 cells. Molecular docking results suggested that kaempferol-3-O-glucoside and tiliroside had good binding ability with enzymes, indicating that they may be potential α-glucosidase and pancreatic lipase inhibitors. Therefore, the E. gardneri flowers could be served as a bioactive agent for the regulation of metabolic disorders.

Improving Quantum Chemical Solvation Models by Dynamic Radii Adjustment for Continuum Solvation (DRACO).

We present the Dynamic Radii Adjustment for COntinuum solvation (DRACO) approach, which employs precomputed atomic partial charges and coordination numbers of the solute atoms to improve the solute cavity. As such, DRACO is compatible with major solvation models, improving their performance significantly and robustly at virtually no extra cost, especially for charged solutes. Combined with the purely electrostatic CPCM and COSMO models, DRACO reduces the mean absolute deviation (MAD) of the solvation free energy by up to 4.5 kcal mol-1 (67%) for a large data set of polar and ionic solutes. Even in combination with the highly empirical universal solvation model (SMD), DRACO substantially reduces the MAD for charged solutes by up to 1.5 kcal mol-1 (39%), while neutral solutes are slightly improved (0.2 kcal mol-1 or 16%). We present an interface of DRACO with two computationally efficient atomic charge models that enables fully automated, out-of-the-box calculations with the widely used program packages Orca and TurboMole.

Surface Redox Reaction for the Synthesis of NiPt Catalysts for the Upgrading of Renewable Ethanol/Methanol Mixtures

Mixtures of ethanol and methanol being synthesized from CO2 and green H2 can serve as sustainable base chemicals for a number of chemical processes. Amongst these processes, the catalytically supported synthesis of CO2-neutral C4 to C10 alcohols is of increasing importance as, e.g., iso-butanol can be used as a drop-in fuel or after dehydration to produce iso-butene as a feedstock for the synthesis of plastics. 2-ethyl-hexanol can be further refined into solvents, tensides, or monomers. In this respect, NiPt alloys on an activated carbon support were found to be active and stable catalysts for the synthesis of iso-butanol following the Guerbet reaction scheme. In this study, two different routes are applied to the synthesis of these NiPt catalysts: a more conventional one based on the impregnation of Ni and Pt salts and an advanced path with a surface redox reaction between elemental Ni on the support and Pt ions in a polar solution. The experimental evaluation shows that the Pt particles from the surface redox reaction being exposed on the Ni particles are more active than those on the impregnated catalysts due to their high surface energy. Their specific space-time yields are 10–20 times higher.

Interaction Parameters for the Formation of Mixed Micelles and Partitioning of Solutes in Them: A Review

When two or more surfactants are mixed, the critical micelle concentration and solubilization capability are changed, and a careful selection of the combination promotes the micelle formation and enhances the solubilizing capability. Thus, understanding the mechanism behind the phenomena is essential for controlling the physical properties of the mixed micelle. The interaction parameters β and B that describe the formation of mixed micelles and their partitioning of solutes, respectively, were proposed by Treiner four decades ago. In this work, data on the formation and partitioning in binary surfactant systems were collected. Although the data on the parameters β and B for polar solutes and theoretical development are still insufficient, the directions of research to acquire an in-depth understanding of the formation and partitioning of the mixed micelle are proposed.

Accelerated Electromigration Approach to Evaluate Chloride-Induced Corrosion of Steel Rebar Embedded in Concrete

Two distinct binary blended concrete mixes were prepared for the study. The first mix involved a cement replacement of 50% slag, denoted as SL. The second mix incorporated a cement replacement of 20% fly ash, referred to as FA. No chlorides were added during the preparation of these concrete specimens. To accelerate chloride transport, electromigration was employed by placing specimens with varying reservoir lengths (ranging from 2.5 cm to 17.5 cm) on their top surfaces. These reservoirs were subsequently filled with a 10% NaCl solution. In this paper, corrosion propagation was monitored over a period of approximately 650 days using electrochemical measurements such as open circuit potential, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS). The evolution of rebar potential, polarization resistance, solution resistance, and corrosion current were analyzed to understand the corrosion behavior. This paper focuses on how the length of the solution reservoirs influences the corrosion-related parameters such as polarization resistance, solution resistance, rebar potential, and corrosion current. During the monitored propagation period, the corrosion current values (last 7 sets of readings) exhibited higher magnitudes for the embedded rebars in specimens made with SL mix in comparison to those made with FA mix. Corrosion current measurements likewise showed an increasing trend as the reservoir lengths increased. None of the specimens had any visible cracks or corroded products that could reach the concrete surface throughout the monitored period. The experimental results provide insights into the corrosion mechanisms and the effectiveness of accelerated corrosion techniques in simulating real-life conditions.

Porous NiTi Dental Implant Fabricated by a Metal Injection Molding: An in Vivo Biocompatibility Evaluation in an Animal Model.

This study assessed the corrosion resistance, intracutaneous reactivity, acute systemic toxicity, and in situ tissue effect of the implantation of porous NiTi fabricated by metal injection molding in animal models. For the intracutaneous reactivity study, five intracutaneous injections were administered per site with and without the tested extract in polar and nonpolar solutions. The extract was also delivered via intravenous and intraperitoneal routes for acute systemic toxicity. TiAl6 V4 (control) and porous NiTi were implanted in rabbit femora for a period of 13 weeks to evaluate the in situ tissue response. Corrosion was evaluated through open and cyclic polarization in PBS, while biocompatibility was investigated by assessing the general conditions, skin irritation score (edema and erythema), and histopathology. No active dissolution or hysteresis loop was observed in the corrosion study. None of the animals exhibited death, moribundity, impending death, severe pain, self-mutilation, or overgrooming. No edema was observed at injection sites. Only the positive control showed an erythematous reaction at 24, 48, and 72 h observations (p < 0.001). Porous NiTi showed a low in situ biological response for inflammation, neovascularization, and fibrosis in comparison to the control implant (p = 0.247, 0.005, and 0.011, respectively). Porous NiTi also demonstrated high pitting corrosion resistance while causing no acute hypersensitivity or acute systemic toxicity. The study concludes that porous NiTi implants were unlikely to cause local sensitization, acute systemic toxicity, or chronic inflammatory reactions in an animal model. Porous NiTi also exhibited osseointegration equivalent to Ti6AI4 V of known biocompatibility.

Theoretical Study on the Optoelectronic Properties of Merocyanine-Dyes.

Merocyanines, as prototypes of highly polar π-conjugated molecules, have been intensively investigated for their self-assembly and optoelectronic properties, both experimentally and theoretically. However, an accurate description of their structural and electronic properties remains challenging for quantum-chemical methods. We assessed several theoretical approaches, TD-DFT, GW-BSE, STEOM-DLPNO-CCSD, and CASSCF/NEVPT2-FIC for their reliability in reproducing optoelectronic properties of a series of donor/acceptor (D/A) merocyanines, focusing on the first excitation energy. Additionally, we tested an all-electron perturbative method based on time-dependent coupled-perturbed density functional theory, denoted as TDCP-DFT. Particular focus was set on direct and indirect solvent effects, which affect excited-state energies by electrostatic interaction and molecular geometry. The molecular configuration space was sampled at the semiempirical tight-binding level. Our results corroborate previous investigations, showing that the S0 - S1 excitation energy strongly depends on the merocyanine molecular structure and the dielectric constant of the solvent. We found significant effects of the polar solution environment on the geometry of the merocyanines, which strongly affect the calculated excitation energies. Taking these effects into account, the best agreement between calculated and measured excitation energies was obtained with TDCP-DFT and GW-BSE. We also calculated excitation energies of molecular crystals at the TDCP-DFT level and compared the results to the corresponding monomers.

Clinically Translatable Solid-State Dye for NIR-II Imaging of Medical Devices.

Medical devices are commonly implanted underneath the skin, but how to real-time noninvasively monitor their migration, integrity, and biodegradation in human body is still a formidable challenge. Here, the study demonstrates that benzyl violet 4B (BV-4B), a main component in the FDA-approved surgical suture, is found to produce fluorescence signal in the first near-infrared window (NIR-I, 700-900nm) in polar solutions, whereas BV-4B self-assembles into highly crystalline aggregates upon a formation of ultrasmall nanodots and can emit strong fluorescence in the second near-infrared window (NIR-II, 1000-1700nm) with a dramatic bathochromic shift in the absorption spectrum of ≈200nm. Intriguingly, BV-4B-involved suture knots underneath the skin can be facilely monitored during the whole degradation process in vivo, and the rupture of the customized BV-4B-coated silicone catheter is noninvasively diagnosed by NIR-II imaging. Furthermore, BV-4B suspended in embolization glue achieves hybrid fluorescence-guided surgery (hybrid FGS) for arteriovenous malformation. As a proof-of-concept study, the solid-state BV-4B is successfully used for NIR-II imaging of surgical sutures in operations of patients. Overall, as a clinically translatable solid-state dye, BV-4B can be applied for in vivo monitoring the fate of medical devices by NIR-II imaging.