Solvent Variation Research Articles

Realizing Abundant Chirality Inversion of Supramolecular Nanohelices by Multiply Manipulating the Binding Sites in Molecular Blocks.

The induction of diverse chirality regulation in nature by multiple binding sites of biomolecules is ubiquitous and plays an essential role in determining the biofunction of biosystems. However, mimicking this biological phenomenon and understanding at a molecular level its mechanism with the multiple binding sites by establishing an artificial system still remains a challenge. Herein, abundant chirality inversion is achieved by precisely and multiply manipulating the co-assembled binding sites of phenylalanine derivatives (D/LPPF) with different naphthalene derivatives (NA, NC, NP, NF). The amide and hydroxy group of naphthalene derivatives prefer to bind with the carboxy group of LPPF, while carboxylic groups and fluoride atoms tend to bind with the amide moiety of LPPF. All these diverse interaction modes can precisely trigger helicity inversion of LPPF nanofibers. In addition, synergistically manipulating the carboxy and amide binding sites from a single LPPF molecule to simultaneously interact with different naphthalene derivatives leads to chirality regulation. Typically, varying the solvent may switch the interaction modes and the switched new interaction modes can be employed to further regulate the chirality of the LPPF nanofibers. This study may provide a novel approach to explore chirality diversity in artificial systems by regulating the intermolecular binding sites.

Solvent-dependent structural and electrochemical properties of zinc cobaltite via a self-assembled mechanism for battery-type supercapacitors

This paper reports the influence of the solvent’s properties on the growth mechanism of zinc cobaltite (ZnCo2O4) microstructures and their surface morphologies. We observed that the ZnCo2O4 microstructures (ZCO) offer a large number of interacting sites due to the solvent variation, influencing the phase purity and high crystallinity of the ZnCo2O4, which strongly affects its electrochemical conductivity. ZCO crystals were synthesized separately in water, ethanol, and isopropyl alcohol solvent at 180 °C for 12 h, governing the formation of 2D sheet-like morphology in water (ZCO-DIW), 3D flower-like and peanut-like morphologies in ethanol (ZCO-ETH), and isopropyl alcohol (ZCO-IPA), respectively. The successful formation of ZCO morphologies was confirmed through high-resolution scanning electron microscopy. Concerning the solvent variation, the specific surface area of the three ZCO electrodes varies in ascending order as ZCO-DIW (23.78 m2 g−1) < ZCO-IPA (27.19 m2 g−1) < ZCO-ETH (37.19 m2 g−1). We also proposed a model for this solvent-dependent formation mechanism of three ZCO electrodes via the self-assembly process. The electrochemical performance of the ZCO electrodes exhibits excellent battery-type behavior with a specific capacity of 98.89 mAh g−1 (for ZCO-ETH) owing to the highly porous flower-like morphology. These results revealed a simple and cost-effective synthesis strategy to fabricate micro/nano-structure with diverse morphology for a wide range of interfacial applications.

Direct π-Activation vs. O-Activation in Halogen-Bonding Catalysis.

Halogen bond donors had an increasing impact on catalysis in recent years, and their development is highly active. In particular, numerous iodine-based halogen bond donors have been developed and used to promote various reactions through coordinating carbonyl groups, a ubiquitous mode of activation in catalysis. We now report computational data which strongly suggests that an alternative activation mode, through direct π-complexation, is operative for unsaturated carbonyl substrates. Calculations also suggest that solvent polarity could have a clear impact on the preference of the mode of activation, raising the possibility of a mechanistic manifold switch through solvent variation. These findings could profoundly impact the development of the next generation of halogen-bond donor catalysts.

Direct π‐Activation vs. O‐Activation in Halogen‐Bonding Catalysis

AbstractHalogen bond donors had an increasing impact on catalysis in recent years, and their development is highly active. In particular, numerous iodine‐based halogen bond donors have been developed and used to promote various reactions through coordinating carbonyl groups, a ubiquitous mode of activation in catalysis. We now report computational data which strongly suggests that an alternative activation mode, through direct π‐complexation, is operative for unsaturated carbonyl substrates. Calculations also suggest that solvent polarity could have a clear impact on the preference of the mode of activation, raising the possibility of a mechanistic manifold switch through solvent variation. These findings could profoundly impact the development of the next generation of halogen‐bond donor catalysts.

Studying the Marangoni effect in double emulsions with a hybrid multi-relaxation time lattice Boltzmann method–finite difference method

Two-phase mass transfer is a critical process in preparing the inertial confinement fusion target microsphere. It is essential to reveal the effect of Marangoni convection on the flow and mass transfer in double emulsions to prepare high-quality microspheres. This paper develops a two-dimensional two-phase flow and mass transfer model based on multi-relaxation time lattice Boltzmann method and finite difference method. The study of the Marangoni effect within the double emulsion under a shear flow is carried out. The results indicate that the slope parameter (which measures the sensitivity of surface tension to the variation of solvent) and initial solvent concentration crucially affect the mass transfer behavior and the magnitude of the Marangoni convection of double emulsions. When the slope parameter is zero, there is no Marangoni convection in the flow field, the magnitude of the vorticity field is minimal, and solvent diffuses uniformly and slowly to the outer water phase. However, at low values of slope parameter, the Marangoni vortex formed within the emulsion is weak, and few plumes appear in the concentration field; at higher values, the magnitude of the vorticity field increases, and a large number of plumes appear and merge. Compared with the slope parameter, the mass transfer process is less sensitive to the initial solvent concentration. Plumes appear and merge at three different initial solvent concentrations. The time required for double emulsions to develop into equilibrium is inversely proportional to the initial solvent concentration.

Characterization and Development of Gelatin from Cow Bones: Investigation of the Effect of Solvents Used for Soaking Beef Bones

Beef bones contain a gelatin component that can be further extracted. This extraction process requires the right solvent to produce good yield and quality. Gelatin has multifunctional properties, namely biodegradable, biocompatible and non-toxic. This is because it is a natural ingredient that contains high amino acids. The most dominant amino acid content as a parameter for determining the quality of gelatin is proline, glycine, and hydroxyproline. The purpose of this study was to study the effect of the solvent used as a medium for soaking cow bones to be converted into gelatin. The solvent variations used include NaOH, HCl, H2SO4, CH3COOH, and NaHCO2. The concentration variations are 4, 5, 6, 7, 8 (%). This research method includes the preparation of cow bone samples, fat removal, mineral removal, soaking for 7 days, and extraction. The extraction process was carried out with variations times of 4 h and 6 h. The results of the study showed that the highest yield value was with 5% HCl solvent with 4 h extraction time of 26.5% with 8.67% water content, 0.9% ash content, pH 4.64, and viscosity 3.19 cP (p &lt; 0.05). A good isoelectric point is produced when using an acidic solvent, which is between 5.3–5.8. The cross-linking of gelatin with chitosan, glutaraldehyde, and glucose was successfully carried out with the FTIR absorption indicator at a wavelength of 3200 cm−1, which indicates the presence of hydrogen bonds, 1022 cm−1, which indicates the breakdown of aldehyde bonds in glutaraldehyde compounds into C-O bonds. According to the microbial test, when gelatin is combined with chitosan, there will be an increase in the microbial inhibition zone. This shows that the development of gelatin materials is very prospective and promising.

Polymorphism of Praziquantel: Role of Cooling Crystallization in Access to Solid Forms and Discovery of New Polymorphs

Praziquantel (PZQ) is an anthelmintic first-line drug to treat schistosomiasis, a neglected tropical disease strongly related to poverty. PZQ crystalline structures and polymorphs have been studied mainly via mechanochemical approaches. This work applies a systematic study to investigate the polymorphism of PZQ using cooling crystallization experiments under different conditions not yet explored in the literature for this compound. We accessed all forms previously reported so far obtained via mechanochemistry and the hydrate found through supercritical CO2 processing. A novel dimethylacetamide (DMA) solvate was obtained, and a new form was discovered after desolvation of the DMA solvate by aging and exposure to water-vapor atmosphere. Toluene and triethylamine were solvents capable of enabling the formation of different forms depending on the employed experimental condition. A new form was discovered using triethylamine as solvent, which differs from all known polymorphs. The results of this work demonstrate that solvent selection and variation in the rate of supersaturation generation can generate forms obtained from more complicated techniques as well as potentially finding new forms.

Efficient route to synthesizing a biocompatible delivery system undergoing morphological changes upon solvent variation

Self-assembled thiobarbiturate-functionalized poly(methyl methacrylate) nanoparticles were synthesized, characterized and tested for their encapsulation and release capabilities.

Unexpected Solvent-Dependent Self-Assembly of Alkali Metal Complexes of Calix[6]-mono-crown-4: Dinuclear Bowls, a Pseudo-Capsule, and a One-Dimensional Polymer.

1,4-Bridged calix[6]-mono-crown-4 (H4L) capable of metal binding was employed, and the influence of solvent variations on the formation of alkali metal complexes (1-6) was investigated. In the crystal, the bowl-shaped H4L host contains one water molecule in a good-fit fashion via H-bonds. When the H4L host was reacted with alkali metal hydroxides (M = Na, K, Rb, and Cs) in chloroform/methanol (solvent A), anion-free dinuclear bowl-shaped complexes of type [M2(H2L)] were isolated regardless of the metal ions. In the dinuclear bowl complexes 1-4, two metal ions (M1 and M2) show different binding behaviors: one (M1) locates inside the pocket like an "egg-in-nest", and the other (M2) positions above the M1 interacting with the calix rim. When chloroform/acetonitrile (solvent B) was used in potassium(I) complexation, interestingly, an elegant pseudo-capsule-type quadrunuclear complex 5 was isolated. In 5, two dipotassium(I) bowls in a rim-to-rim arrangement are triply bridged by one water and two acetonitrile molecules like a magic glue. However, in dichloromethane/methanol (solvent C), cesium(I) yielded an infinite product 6 in which dicesium(I) bowls are linked by cation-π interactions, giving rise to a one-dimensional zigzag coordination polymer. Taken collectively, all products share a dinuclear bowl unit, some of which are further extended to the pseudo-capsule or polymeric array, depending on the solvents. The results suggest the solvent variation as a versatile engineering tool and present a perspective on the metallosupramolecules of calix[6]-mono-crowns with monomer, dimer (e.g., pseudo-capsule), and polymer topologies.

The Potential of Pineapple Crown (Ananas Comosus) as Removal of Kidney Stone

Some people in Mojokerto use pineapple crowns as medicine to remove a kidney stones. However, research related to this topic is very limited, there is no specific data regarding the content of active substances in pineapple crown. So that in this study, kidney stone decay was tested with pineapple crown extract and analyzed the phytochemicals of pineapple crown were. The effect on the ability of pineapple crown to remove kidney stones was carried out in vitro by testing kidney stones obtained from one of the patients with kidney stone disease. The solubility of calcium oxalate which is the content of kidney stones was tested against pineapple crown extract with various solvents. While the phytochemical test was carried out 6 times on the extraction of pineapple crown with various solvent variations. From the results of tests carried out on the content of several phytochemical compounds such as saponins, tannins, flavonoids, triterpenoids, and steroids, it was found that the highest content was found in pineapple crown extract with water and ethanol solvents. From the in vitro test results of kidney stone solubility, it was found that there was an effect of pineapple crown on kidney stone solubility although it was not significant. The optimum concentration of pineapple crown extract from several variations of the concentration tested was 0.0625 M. Through this research, can provide scientific facts to the public about the use of pineapple crown extract for kidney stone removal.

Real-Time 1H and 31P NMR spectroscopy of the copolymerization of cyclic phosphoesters and trimethylene carbonate reveals transesterification from gradient to random copolymers

Copolymerization is the general approach to combine properties of different polymers in a single material. We prepared the first trimethylene carbonate (TMC) phosphoester (PE) copolymers by statistical copolymerization using either stannous octanoate or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the respective catalyst. Variation of comonomer feed, reaction temperature and solvent, resulted in a library of copolymers with molar masses of up to 83,000 g/mol and moderate molar mass dispersities (<1.8). The monomer consumptions during the copolymerizations were followed by real-time 1H and 31P NMR spectroscopy in solution and in the bulk. As ring-opening copolymerization of cyclic esters often leads to gradient copolymers, also TMC and PE copolymerizations resulted in gradient copolymers, i.e. P(TMC-grad-PE)s, with different gradient strength depending on the copolymerization conditions. If a suitable transesterification catalyst like stannous octanoate was used, randomization of the gradient copolymer occurred. The 31P NMR shift of incorporated phosphoester units was used as a probe to monitor the randomization of the gradient copolymers in real-time by 31P NMR spectroscopy. The P-comonomer acts as an ideal NMR probe for in situ monitoring the changes of the copolymers’ microstructure during the transesterification by following the evolution of diads and triads. This paper focusses on the randomization procedure and gives detailed information about the copolymer structure and the kinetics of the copolymerization. The data give the possibility to understand randomization processes on a molecular scale and to fine-tune properties of polycarbonate-polyphosphoester copolymers in future applications.

Insights into solvent effects on molecular properties, physicochemical parameters, and NLO behavior of brinzolamide, a bioactive sulfonamide: A computational study

In this study, quantum chemical calculations performed on brinzolamide (BZ), a sulfonamide derivative widely used as an antibacterial and antifungal drug, are presented. The molecular geometry optimizations of BZ were calculated by using both B3LYP functional and HF method with the 6-31G (d, p) basis set via Gaussian software. Since solvent phase behaviors are extremely important especially for drug molecules, calculations were renewed for BZ in ten different solvent environments. Universal solvation model SMD (Solvent Model based on Density) was utilized for solvent phase simulations. Mulliken and natural atomic charges, frontier molecular orbital (FMO) energies, quantum chemical descriptors were studied in detail according to solvent and method variation. In addition, the partition coefficient (logPow) value, which is an important parameter for the activity of the drug candidates, was theoretically estimated according to the relevant formula through the computed values for the water and 1-octanol phases for each methodology. The slightly lipophilic character of the BZ molecule was supported by the obtained values and the molecular lipophilicity potential map prepared by means of Molinspiration Galaxy 3D Structure Generator v2018.01 beta program. In the nonlinear optical (NLO) property analysis, dipole moment (μtot), mean polarizability (αtot), anisotropic polarizability (Δα), and mean first-order hyperpolarizability (βtot) values of BZ and the solvent effect on these values have been reported. Last, the interaction energies between donor and acceptor orbitals were calculated by the analysis of natural bond orbitals, and the obtained results were summarized.

Synthesis of Stober silica nanoparticles in solvent environments with different Hansen solubility parameters

• Changing the solvent in the Stober synthesis is a good tool to control particle size. • The addition of non-polar liquids results formation of smaller particles. • Dispersion and polar thermodynamic parameters influence on nanoparticle size. • A decrease of hydrogen interaction index leads to size increase of nanoparticles. The most commonly used technique for obtaining SiO 2 nanoparticles of controlled size is the Stober synthesis. In this paper, a series of Stober syntheses in media with different thermodynamic parameters are described and the obtained nanoparticles were characterized by electron microscopy. As a result, it was shown that the solvent variation in the Stober synthesis is a working tool for controlling the particle size of silica. The addition of nonpolar liquids to the reaction mixture led to the formation of smaller particles. Also, it was found that an increase in the dispersion and polar parameters of the solvent leads to an increase in the size of the resulting SiO 2 nanoparticles. The same observations were obtained with a decrease in the index of hydrogen interactions between solvent molecules.

Cosolvent effect on morphogenic changes of self-assembled aggregates from biodegradable polylactones

The solvent variation effect on the self-assembly phenomenon is discussed in this article. Two different biodegradable backbones of the same community (polycaprolactone and polylactide) were selected to visualize the morphological changes upon treatment of different solvents/cosolvents. The curiosity was to observe if the change occurred only with the solvents or it was assisted to the backbones also. Tetrahydrofuran, acetonitrile and 1,4 dioxane were used as polar aprotic solvent whereas, methanol was used as polar protic one with the common solvent water in each case. The macromolecular aggregates were formed using the solvent mixture and their morphological or conformational changes were monitored using different conventional techniques such as Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and cryo-Transmission Electron Microscopy (cryo-TEM).The spontaneously formed superstructures were thoroughly characterized and well documented here. The hierarchical aggregates disclosed here bears the potential of vast usage in the field of nanotechnology.

Synthesis and Characterization of Cellulose Acetate Membrane from Cigarette Butts as Gel Polymer Electrolytes for Lithium-Ion Battery

In this study, polymer electrolyte gel membranes (GPEs) as separators in Lithium-Ion battery cells were prepared using polymer blends between polyvinylidene fluoride (PVDF) and cellulose acetate (CA). The CA used was obtained from the recovery process from cigarette butts. The prepared GPEs showed increased thermal stability and membrane strength. This research consists of two stages, the CA recovery process from cigarette butts is the initial stage, then the next stage is the synthesis of GPEs membranes. In the CA recovery process from cigarette butts, using a solvent mixture of ethanol and toluene with the ratio of 1:1.0, 1:1.1, 1:1.2, and 1:1.3 respectively. Furthermore, CA was characterized using XRD, FTIR, and SEM methods. The characterization results showed that the solvent variation of 1:1.3 produced CA with the most suitable properties with commercial CA. In the synthesis stage, GPEs were made using the Non-solvent Induced Phase Separation method. Membrane solutions were prepared by mixing PVDF/CA polymers with variations of cellulose acetate (2, 4, 6, 8, and 10% wt), PVP additives, and ZnO filler. This solution is then printed on glass and then immersed in a non-solvent (water) for the solidification process of membranes. The result shows that the modified GPEs have the best porosity and electrolyte uptake properties of 79.05% and 942.105%, respectively, in the modification with the addition of 10% wt CA.

Utilization of Natural Dyes Solutions and Glycerol for the Quality and Durability of Direct Wet Mount Preparations Storage in Educational Laboratories

Educational laboratories require the availability of direct wet mount preparations that can last a long time with good quality. Various studies have mentioned techniques so that preparations can last a long time. This study aims to analyze the composition of dyes and glycerol in wet preparations of worm eggs on the quality and shelf life of the preparations. The solvent variations used for the wet preparations were Angkak 2%, and eosin 2%, with the addition of variations in the concentration of glycerol 20%-45%. The number of treatments and repetitions in the study was 70 samples, which were observed in the first, second, third, and fourth weeks. Based on the ANOVA test, the results showed a significant effect on the parameters measured, namely the type of dye, the type of slide, and the shelf life of the preparation (storage) in natural dye solution (2% ethanol extract of Angkak solution) and synthetic dye solution (2% eosin solution). The correlation test results of storage time treatment on the clarity of the preparations showed that the longer the storage, the lower the clarity of the preparations (r=-0.46246). The correlation test results of storage time treatment on the contrast of the preparations showed that the longer the storage, the less the contrast was not so strong (r=-0.26375). The correlation test results of storage time treatment on the quality of the preparations showed that the longer the storage, the lower the quality of the preparations (r=-0.51346). The conclusion is that the best quality of wet preparations is preparations that are stored for four weeks using a flat object-glass with a mixture of 1:1 dye solution of 2%-glycerol solution of 35% and 1:1 mixture of a 2%-glycerol solution of 1:1 solution. Further research is needed on the concentration of the dye solution mixture to find the best formulation for improving the quality and resistance of wet preparations.

Diastereodivergent Synthesis of Cyclopentyl Boronic Esters Bearing Contiguous Fully Substituted Stereocenters.

The synthesis of molecules bearing two or more contiguous, quaternary stereocenters is challenging, owing to the difficulty in controlling stereochemistry whilst simultaneously constructing a sterically congested motif. Herein, we report the electrophile‐induced ring contractive 1,2‐metallate rearrangement of 6‐membered cyclic alkenyl boronate complexes for the synthesis of cyclopentyl boronic esters bearing two contiguous, fully substituted stereocenters with high levels of stereocontrol. Remarkably, simple variation of the reaction solvent enabled their diastereodivergent construction with facile access to complementary diastereomeric pairs. The utility of our methodology is demonstrated in the asymmetric total synthesis of (+)‐herbertene‐1,14‐diol.

Diastereodivergent Synthesis of Cyclopentyl Boronic Esters Bearing Contiguous Fully Substituted Stereocenters

AbstractThe synthesis of molecules bearing two or more contiguous, quaternary stereocenters is challenging, owing to the difficulty in controlling stereochemistry whilst simultaneously constructing a sterically congested motif. Herein, we report the electrophile‐induced ring contractive 1,2‐metallate rearrangement of 6‐membered cyclic alkenyl boronate complexes for the synthesis of cyclopentyl boronic esters bearing two contiguous, fully substituted stereocenters with high levels of stereocontrol. Remarkably, simple variation of the reaction solvent enabled their diastereodivergent construction with facile access to complementary diastereomeric pairs. The utility of our methodology is demonstrated in the asymmetric total synthesis of (+)‐herbertene‐1,14‐diol.

Effect of Vehicle Composition on the Preparation of Different Types of Dapsone Crystals for Topical Drug Delivery.

Topical formulations composed of API-pure crystals have been increasingly studied, especially in regards to the impact of particle size in penetration efficiency. Less attention, however, has been devoted to the solid-state properties of drugs delivered to the skin. In this study, we address the effect of formulation composition on the crystal form existing in topical products. Dapsone (DAP) gel formulations were prepared by mixing an organic solution containing DAP with an aqueous solution containing polymers and preservatives. The organic solvent was chosen as ethoxydiglycol (DEGEE), polyethylene glycol (PEG), or 1-methyl-2-pirrolidone (MPR) to assess the impact of composition on DAP crystal form. Such solvent variations resulted in different particulate matter. In terms of crystalline nature, the presence of DEGEE in formulations induced the crystallization of DAP hydrate, while PEG cocrystal and a mixture of hydrate and MPR solvate crystallized from the same amounts of PEG and MPR, respectively. Microscopic analysis of the gels showed heterogeneous particles with different characteristics. The behavior of gels after application to the skin was also tested. Interestingly, the different formulations seemed to accumulate in different regions of the skin. This could be the result of the effect of vehicle composition/excipients on the characteristics of the skin, such as hydration. The site-specific accumulation, however, was more pronounced in crystal-loaded gels as opposed to blank formulations. These results indicate that future studies should consider the effect of formulation composition on the API crystal form landscape as part of the strategies used to successfully target drug delivery to the skin.

Penentuan Aktivitas Antioksidan, Kandungan Fenolik Total, dan Uji Sitotoksik dari Ekstrak Rumput Banto (Leersia hexandra Swartz.)

Banto grass, known as animal feed and tradicional medicine, has anticancer, antioxidant, and antihypertensive effect. The purpose of this study was to determine the secondary metabolite content, antioxidant activity, total phenolic content and cytotoxic activity. Maceration extraction with variation of solvent (hexane, ethyl acetate, and methanol) was used to obtain the banto grass extract. Antioxidant activity of the banto grass and control determined using 1,1-Diphenyl-2-picrylhydrazil (DPPH) method: Methanol (IC50 154,75 mg/L), Ethyl Acetate (IC50 224,47 mg/L) and Hexane (IC50 268,59 mg/L). Vitamin C (IC50 9,31 mg/L) served as control.The methanol extract had weak antioxidant activity while ethyl acetate and hexane extract had very weak antioxidant activity. The banto grass was screened for total phenolic content using Folin-Ciocalteu method: Methanol (0,3 mg GAE/g dry extract), Ethyl Acetate (0,23 mg GAE/g dry extract), and Hexane (0,11 mg GAE/g dry extract). There was negative correlation between IC50 and total phenolic content of the banto grass extract. Cytotoxic activity of the banto grass determined using Brine Shrimp Lethality Test (BSLT) method: Methanol (LC50 2454, 14 mg/L), Ethyl Acetate (LC50 233,13 mg/L) and Hexane (LC50 220,39 mg/L). The hexane and ethyl acetate extract had toxic properties while methanol extract had not toxic properties.