Length Of Substituent Research Articles

Interaction between newly synthesized surface-active ionic liquids with pharmaceutically active anion and bovine serum albumin

This work describes the synthesis and properties of new surface active (octyl-, and dodecyl-) imidazolium and choline-based ionic liquids with pharmaceutically active 5-fluorouracil anion (SAAPI-IL). The effect of the novel SAAPI-IL on the secondary and tertiary structure of bovine serum albumin (BSA) was studied using circular dichroism (CD) spectroscopy. The binding constants of BSA with SAAPI-IL were estimated from the fluorescence quenching of BSA. The influence of the length of the alkyl chain SAAPI-IL on the binding constant with BSA was analyzed. The localization of ions on BSA was estimated using the molecular docking method. Also, the effect of alkyl substituent length on the aggregation tendency of SAAPI-IL was studied by dynamic light scattering (DLS). Cytotoxicity and selectivity of SAAPI-ILs on cancer and normal cell lines were compared to molecular 5-fluorouracil and API-IL without the alkyl substituents. Surprisingly, increasing the length of the alkyl substituent did not increase the binding of SAAPI-IL to BSA. On the other hand, [C8Ch][FU] showed selectivity against A 549 cell line, which 5-fluorouracil does not possess.

The influence on combustion and emissions of alkyl chain length in gamma and delta lactones in a heavy-duty diesel engine

Heavy-duty engines used in transport are particularly challenging to decarbonise as they cannot be easily replaced by alternative powertrains, and it remains likely that many industries will remain reliant on conventional fuels for the foreseeable future. To reduce the emissions of CO2 from heavy-duty engines, the approach of using biofuels is of interest as this would require little modification to existing vehicle fleets. Biodiesels (fatty acid methyl esters) are already widely used as a drop in biofuel for diesel, but continual growth in supply is limited by feedstock scarcity, as vegetable oils compete with the food supply. Lactones are a class of cyclic esters which can be produced from second generation biomass, a globally abundant feedstock. As esters their chemical reactivity and stability is similar to that of common biodiesels, and previous literature suggests these compounds have desirable ignition qualities and as oxygenates lower particulate emissions. In this study, the combustion and emissions characteristics of a series of isomeric gamma and delta lactones with increasing alkyl chain lengths, from C4 to C8, as single component test fuels in a heavy-duty compression ignition engine. It was found that increasing the length of the alkyl substituent chain adjacent to the ring bound oxygen within the lactones reduced the duration of ignition delay, resulting in a smaller premixed burn fraction during combustion and decreasing emissions of nitrogen oxides, unburnt hydrocarbons and carbon monoxide. For the majority of the lactones an equivalent isomer was also tested, allowing for comparisons on between equivalent carbon count or substituent alkyl chain length. Gamma lactones compared to delta lactones of the same carbon number exhibited a shorter duration of ignition delay and apparent peak heat release rate. When comparing lactones of different ring size with the same length of the substituent alkyl chain, the delta lactones initially exhibited a shorter duration of ignition delay, longer duration of combustion and lower unburnt hydrocarbons and carbon monoxide emissions.

A ratiometric fluorescent sensing foil for high resolution 2D pH measurement based on a novel hydroxy-pyrene green fluorophore

The pH of environmental systems plays a crucial role in determining pollutant behavior, necessitating the development of effective tools for real-time monitoring. This study introduces a novel series of lipophilic HPTS derivatives, developed through a two-step synthesis route, designed as pH-sensitive dyes, characterized by high fluorescence intensity, photostability, dual excitation/single emission, and significant Stokes shifts. We engineered self-ratiometric pH-sensing planar optode foils and investigated the impact of carbon chain length on foil durability. These foils demonstrate reliable quantitative pH detection across a range of 6.5–9.5 using commercial imaging systems and maintain exceptional photostability with minimal ionic interference. Notably, foils constructed with HPTS(DPA)3 derivatives, where the substituent carbon chain length is longer than six carbons show no significant leakage under varying pH conditions. The practical application of the foil was validated by mapping the two-dimensional pH distribution in the soil rhizosphere around rice roots at a resolution of 17 megapixels, demonstrating the potential for environmental monitoring applications.

MOLECULAR COMPLEXES BASED ON para-ALKYLSULFONIC ACIDS AND PYRIDINE DERIVATIVES: STRUCTURE AND MESOMORPHIC PROPERTIES

The paper presents the results of theoretical and experimental studies of new mesogenic molecular complexes based on 4-alkylsulfonic acids and 4-pyridyl-4'-n-alkyloxybenzoates. Using quantum chemistry methods (DFT), the structural units of the systems under study, which are hydrogen-bonded complexes, were modeled. The relationship between molecular parameters, electronic effects of substituents, gas-phase acidity and characteristics of the formed H-complexes is shown. Electron-donating alkyl substituents in the para-position of benzenesulfonic acid reduce gas-phase acidity compared to the unsubstituted molecule, enhancing the electron-withdrawing properties of the sulfo group. The type and potential barrier of the calculated potential functions of proton transfer from the sulfo group to the pyridine fragment in the molecular complexes under study allowed us to conclude that gas-phase acidity directly determines the characteristics of this process. It was found that para-alkyl-substituted benzenesulfonic acids form stronger hydrogen bonds in proton transfer complexes compared to unsubstituted benzenesulfonic acid. The synthesis of three samples of molecular complexes of 1:1 composition was performed (4-methylbenzenesulfonic acid : 4-pyridyl-4'-n-dodecyloxybenzoate, 4-ethylbenzenesulfonic acid : 4-pyridyl-4'-n-heptyloxybenzoate, 4-ethylbenzenesulfonic acid : 4-pyridyl-4'-n-dodecyloxybenzoate). IR spectra recorded at room temperature showed that the systems under study are H-complexes with proton transfer from the sulfo group to the pyridine fragment with an intermolecular hydrogen bond of the N–H∙∙∙O type. It was determined that all H-complexes have enantiotropic mesophorism, as evidenced by DSC and polarization thermomicroscopy data. The recorded mosaic textures in a polarizing microscope suggested that the samples under study had a smectic type of mesophase. It has been shown that the temperatures of phase transitions from the mesophase to the isotropic liquid phase depend on the length of the alkyl substituents in the components of the complexes, which may be a manifestation of the odd-even effect. For citation: Fedorov M.S., Filippov A.A., Syrbu S.A., Kiselev M.R. Molecular complexes based on para-alkylsulfonic acids and pyridine derivatives: structure and mesomorphic properties. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 12. P. 64-72. DOI: 10.6060/ivkkt.20246712.7094.

Enhanced Photovoltaic Performance of Poly(3,4-Ethylenedioxythiophene)Poly(N-Alkylcarbazole) Copolymer-Based Counter Electrode in Dye-Sensitized Solar Cells

Conducting polymers are emerging as promising alternatives to rare and expensive platinum for counter electrodes in dye-sensitized solar cells; due to their ease of synthesis, they can be chemically tuned and are suitable for roll-to-roll production. Among these, poly (3,4-ethylenedioxythiophene) (PEDOT)-based counter electrodes have shown leading photovoltaic performance. However, certain conductivity issues remain that affect the effectiveness of these counter electrodes. In this study, we present an electropolymerized PEDOT and poly(N-alkylated-carbazole) copolymer as an efficient electrocatalyst for the reduction in I3− in dye-sensitized solar cells. Copolymerization with N-alkylated carbazoles significantly increases the conductivity of the polymer film and facilitates rapid charge transport at the interface between the polymer electrode and the electrolyte. The length of the alkyl substituents also plays a crucial role in this improvement. Electrochemical analysis showed a reduction in charge transport resistance from 3.31 Ω·cm2 for PEDOT to 2.26 Ω·cm2 for the PEDOT:poly(N-octylcarbazole) copolymer, which is almost half the resistance of a platinum-based counter electrode (4.12 Ω·cm2). Photovoltaic measurements showed that the solar cell with the PEDOT:poly(N-octylcarbazole) counter electrode achieved an efficiency of 8.88%, outperforming both PEDOT (7.90%) and platinum-based devices (7.57%).

Efficient photocatalytic degradation of 24 imidazolium ionic liquids in an N-ZnO/simulated sunlight irradiation system and its mechanism

An efficient nitrogen (N)-ZnO photocatalytic composite was synthesized and well characterized to demonstrate its superior photocatalytic performance as well as the degradation kinetics of 24 ILs in an N-ZnO/Xe lamp irradiation system, as well as the pathways and mechanisms of the photocatalytic degradation (PCD) of typical ionic liquids [OMIm]Br was systematically studied. To investigate the catalytic effect, nitrogen was synthesized from various inorganic and organic nitrogen compounds to ZnO. The NH4NO3-ZnO composite calcined at 300 °C with a molar ratio of NH4NO3 to Zn(NO3)2·6H2O of 10:1 exhibited superior catalytic performance as assessed by SEM, TEM, FT-IR, UVDRS, BET surface area, XPS, and XRD characterizations. After 24 h of exposure to Xe lamp irradiation, all 24 ILs were significantly degraded by the introduction of 0.125 g/L of catalyst, whereas simulated sunlight alone resulted in minimal degradation. The pseudo-first-order rate coefficients (k) for PCD were closely related to the carbon chain length of the alkyl substituents and the type of anion. Multiple linear regression analysis indicated no linear correlation between the parameters E, H°, Eth, and Cv° from the Gaussian calculation and k. Conversely, a positive correlation was observed for EHOMO (B=0.742, β = 1.282, P = 0.011), qH+ (B=1.040, β = 3.284, P = 0.006), and G° (B=0.001, β = 5.400, P = 0.007) with k. Mass spectrometry analysis revealed that the primary PCD pathway for [OMIm]Br involved C-N and/or C-C bond breaking, mono-, di-, and tri-hydroxylation, single and double oxygen transfer, and bromo-substitution reactions.

Effect of the Chemical Nature of MQ Copolymers on the Rheological Properties of Compositions on Their Basis

The rheological and rheokinetic properties of the compositions based on low-molecular rubber polyisoprene and MQ copolymer particles with decyl terminal groups were studied. The effect of the ratio of M and Q units in the copolymer on the rheological and mechanical properties of the compositions was analyzed. An increase in the length of a hydrocarbon substituent in M units was shown to lead to an increase in the affinity of the copolymer to the carbon-chain polymer matrix. An increase in the content of Q units facilitates the growth of the elastic modulus of the cured composites.

Синтез производных класса 2-алкил-5-фенил-4,5,6,7- тетрагидро-[1,2,4]триазоло[1,5-a]пиримидин-7-ола

The problem of acid corrosion of steel is of significant importance, particularly in the context of the oil extraction industry, where acid treatment of wells and surrounding spaces is widely employed. This research article focuses on the synthesis and investigation of previously unstudied derivatives of the class of 2-alkyl-5-phenyl-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-a]pyrimidin-7-ols – organic compounds potentially highly effective as inhibitors of acid corrosion of steel. The method for synthesizing the proposed compounds involves the condensation of 3-alkyl-5-amino-1H-1,2,4-triazoles with cinnamaldehyde. The structure of the synthesized compounds has been confirmed using 1H NMR and LCMS methods. The study has revealed that the developed synthesis conditions yield the target tetrahydrotriazolopyrimidinols with alkyl substituents containing up to three carbon atoms. However, an increase in the length of alkyl substituents intensifies side reactions, making the isolation of the target compounds challenging. The obtained research results are significant for the development of effective organic inhibitors of acid corrosion of steel of a new class. These findings can serve as a basis for further research in this area, contributing to the development of new methods for corrosion prevention and improving the resistance of materials used in the oil industry. Thus, this study not only describes a new synthetic approach to obtaining inhibitors of corrosion in the tetrahydrotriazolopyrimidinol class but also holds prospective practical value in the field of industrial technologies and materials science.

IGC investigation of the effect of the length of the n-alkyl substituent in 5-alkylsubstituted norbornenes on solute retention

Polymerization of 5-n-alkyl-substituted 2-norbornenes synthesized a series of polymers having the same structure of the main polymer chain, but differing in the length of the alkyl substituent (up to 14 methylene units). The obtained polymers were studied by the capillary IGC method as a stationary phase during separation of a mixture of normal hydrocarbons C6-C10. Retention data in the form of a logarithm of the retention factor lnk were correlated with the size of the sorbate (via the carbon number of the alkane ZS) and with the size of the n-alkyl substituent in the polymer chain (via the carbon number of the polymer ZP). Correlation of lnk vs. ZS turned out to be linear for all polymers, but the angle of the slope of linear dependence dlnk/dZS increases with a decrease in the carbon number of the polymer ZP. Dependency of dlnk/dZS vs. ZP is not linear and indicates an increase in the retention of sorbates by the stationary phase with a decrease in the length of the alkyl substituent in the polymer chain. The correlation of the retention of lnk analytes with the carbon number of the polymer ZP is not linear and indicates an increase in the sorbate/sorbent interaction with a decrease in the length of the alkyl substituent. Inflection points were found at both correlations with ZP in the region of ZP = 8, which indicates a possible change in the sorption mechanism or a change in the phase state of the polymer. In polymer chemistry, the phase state of a polymer is characterized by the glass transition temperature Tg, the dependence of which vs. ZP turned out to be nonlinear with an inflection point at ZP ∼11. Thus, a decrease in the length of the alkyl substituent leads to the transition of the polymer from a rubbery state to a glassy one at ZP ∼ 11, which in turn, with a further decrease in the carbon number of the polymer to ZP ∼ 8, causes a change in the sorption mechanism from bulk sorption to surface sorption. The change in the sorption mechanism is accompanied by an increase in the interaction of the sorbate with the stationary phase, which manifests itself both in an increase in the retention time of analytes and in an increase in the enthalpy and entropy of sorption. The reason for this increase can be seen in the formation of a microporous structure in 5-alkyl-substituted polynorbornenes in a glassy state.

SYNTHESIS OF POLYACRYLAMIDE HYDROGELS WITH PORPHYRIN FRAGMENTS IN THE SIDE CHAIN IN THE PRESENCE OF IMIDAZOLIUM IONIC LIQUIDS

The acrylamide hydrogels containing the porphyrin fragments have been obtained by radical polymerization in a solution. The synthesis has been carried out in the presence of imidazolium ionic liquids with length of the alkyl substituent in the imidazolium ring from C4 to C8. The influence of the used ionic liquids on the structure and some properties of the resulting porphyrin-containing acrylamide hydrogels has been established. The addition of an ionic liquid with a different length of the alkyl substituent into the reaction system can influence the structural changes that occur with the porphyrin comonomer during copolymerization with acrylamide. The formation of bacteriochlorin-like structures is inhibited in the presence of an ionic liquid in the reaction medium. This effect is most noticeable when using an imidazolium ionic liquid with a C8 alkyl substituent length. Hydrogels synthesized in the presence of ionic liquids have lower specific surface area compared to ones obtained without the use of ionic liquids. The lowest specific surface area values were shown by hydrogels synthesized using 1-octyl-3-methylimidazolium bromide. It was also found that the introduction of ionic liquid into the reaction mixture can contribute to both increase and decrease in the numerical values of the sorption characteristics of the resulting hydrogels, depending on the length of the alkyl substituent in the imidazolium ring and a porphyrin : acrylamide ratio. Hydrogels synthesized using 1-hexyl-3-methylimidazolium bromide and 1-octyl-3-methylimidazolium bromide at an initial porphyrin : acrylamide ratio of 1:20 have the highest degree of swelling. Varying the ratio of the initial monomers and the structure of the imidazolium ionic liquid during the copolymerization process allows to control the physicochemical characteristics of the resulting porphyrin-containing hydrogels, which can be useful for solving various applied problems. For citation: Pechnikova N.L., Smirnov A.S., Lyubimtsev A.V., Aleksandriiskiy V.V., Ageeva T.A. Synthesis of polyacrylamide hydrogels with porphyrin fragments in the side chain in the presence of imidazolium ionic liquids. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 6. P. 73-79. DOI: 10.6060/ivkkt.20246706.7053.

Design, Synthesis and Anti-cancer Evaluation of Nitrogen-containing Derivatives of 30-Carboxyl of Gambogic Acid.

Gambogic acid (GA) is a natural product from the resin of the Garcinia species, which showed significant activity in the induction of apoptosis. .t can be one promising lead compound for the design and synthesis of new anticancer drugs. The objective of the current study is to design novel nitrogen-contained GA derivatives with better anti-cancer activities and study the effect of the introduction of different nitrogen-contained groups on the activity of GA. The designed 15 derivatives were synthesized via esterification or amidation of 30-carboxylate. The synthetic compounds were characterized via different spectroscopic techniques, including X-ray single crystal diffraction, MS and NMR. The cytotoxic activity of the designed derivatives was evaluated in vitro against A549, HepG-2, and MCF-7 cell lines using methyl thiazolyl tetrazolium (MTT) test. 15 nitrogen-contained GA derivatives were successfully synthesized and established. Based on the IC50 values, compounds 9, 10, 11 and 13 showed stronger inhibitory effects on A549, HepG-2, MCF-7 cell lines than GA, while 9 is the most active compound with IC50 value of 0.64-1.49 μM. Most derivatives of GA with esterification of C-30 including cyano-benzene ring were generally weaker than those of pyrimidinyl-substituted derivatives. In addition, length of alkyl linkers between C-30 of GA and nitrogen-contained group produced different effects on A549, HepG-2 and MCF-7 cell lines. The structure-activity relationship results show that aromatic substituent and linker length play important roles to improve the anticancer activities, while compound 9 with pyrimidine substituent and C-C-C linkers is the most active derivative against tested cell lines, and is a promising anti-cancer agent for further development.

Molecular mechanism for the absorption of ketone volatile organic compounds by ionic liquids

With the development of industry, volatile organic compounds (VOCs) have received increasing attention as a class of pollutants that need to be eliminated due to their adverse effects on the environment and human health. As a new green solvent, ionic liquids (ILs) are regarded as the excellent alternative to traditional organic absorbents. To investigate the effect of IL structure on its capture of VOCs, [BMIM][TF2N], [BIM][TF2N], and [EIM][TF2N] were used as acetone absorbents in this work, and the mechanism was revealed microscopically by quantum chemical calculations in conjunction with the COSMO-RS model. The results suggested that acetone tends to bind to protonic ILs more than the same type of nonprotonic ILs. For protonic ILs, changing the length of the cationic substituent has little effect on the results. Therefore, ILs with short substituent can increase the mass absorption of acetone without essentially changing the mole absorption, thus facilitating the industrial application.

Influence of the length of end-group double bond substituents on the temperature change of phase transition in liquid crystals

ABSTRACT A series of nematic liquid crystal (LC) monomers, containing a reactive group in the lateral substituent, were designed and synthesised through an organic synthesis reaction. Considerable changes were made to the properties of the liquid monomers by varying the terminal alkyl chain lengths. The molecular structures of the intermediates and the LC monomers were characterised by flourier infrared absorption spectrometry and proton nuclear magnetic resonance (1H NMR) spectroscopy, leading to the identification of the target product. The phase transition temperatures of the LC monomers were observed and analysed using differential scanning calorimetry (DSC) and polarising optical microscopy (POM) with a hot stage. The two-way thermotropic liquid crystalline behaviour was observed during the heating process, providing insight into the effect of substituent changes on the phase transition temperature.

Investigating the Structure-property Relationships of Two Cd-based Hybrid Multifunctional Compounds with High Tc, Bright Fluorescence and Wide Band-gap.

Organic-inorganic hybrid multifunctional materials have shown significant application in lighting and sensor fields, owing to their prominent performance and diversity structures. Herein, we synthesized two multifunctional compounds: (propyl-quinuclidone)2 CdBr4 (1) and (F-butyl-quinuclidone)2 CdBr4 (2). By introducing light-emitting organic cation with flexible long chain, 1 and 2 exhibit excellent transition properties and bright blue-white fluorescence. Then, combine fluorescence lifetime and first-principal calculation, providing evidence for the electron transfer emission. Subsequently, investigated the impact of substituent carbon chain length (methyl to butyl), structural rigidity (C-C to C-F) and halide framework (Cl to I) on the fluorescence properties. Results indicate that Cd⋅⋅⋅Cd distance and structural rigidity play an important role in fluorescence. Overall, our research provides valuable insight and example for chemical modifications enhance compound performance.

Unveiling the power of liquid chromatography in examining a library of degradable poly(2-oxazoline)s in nanomedicine applications.

A library of degradable poly(2-alkyl-2-oxazoline) analogues (dPOx) with different length of the alkyl substituents was characterized in detail by gradient elution liquid chromatography. The hydrophobicity increased with increased side chain length as confirmed by a hydrophobicity row, established by reversed-phase liquid chromatography. Those dPOx were cytocompatible and formed colloidally stable nanoparticle (NP) formulations with positive zeta potential. Dynamic light scattering (DLS) revealed that dPOx with increased hydrophobicity tended to form NPs with increased sizes. NPs created from the most hydrophobic polymer, degradable poly(2-nonyl-2-oxazoline) (dPNonOx), showed tendency for aggregation at pH 5.0, and in the presence of protease in solution, in particular for NPs formulated without surfactant. Liquid chromatography revealed enzymatic degradation of dPNonOx NPs, clearly demonstrating the disappearance of polymer signals and the appearance of hydrophilic degradation products eluting close to the chromatographic void time. The degradation process was confirmed by 1H NMR spectroscopy. dPNonOx NPs containing the anti-inflammatory drug BRP-201 as payload reduced 5-lipoxygenase activity in human neutrophils. Thereby, composition analysis of the resultant NPs, including drug quantification, was also enabled by liquid chromatography. The results indicate the importance of a detailed analysis of the final polymer-based NP formulations by a multimethod approach, including, next to standard applied techniques such as DLS/ELS, the underexplored potential of liquid chromatography. The latter is demonstrated to resolve a fine structure of solution composition, together with an assessment of possible degradation pathways and is versatile in determining hydrophobicity/hydrophilicity of polymer materials. Our study underscores the power of liquid chromatography for characterization of soft matter drug carriers.

Impact of the aliphatic side chain length on photovoltaic properties of fullerenes functionalized with 3-(1-indenyl)propionic acid esters

10 Indene C60 and C70 derivatives have been synthesized and characterized, and solar cells fabricated using them gave the best efficiency for hexyl derivatives.

The influence of the alkoxy substituent length on the crystal structures of Tc(v) complexes with pyrazine

This paper reports the synthesis, X-ray and spectral characterization of pyrazine Tc(v) complexes with alkoxy ligands (from CH3 to C10H21). An increase in the chain length leads to a linear decrease in the decomposition temperature of the complex.

Precise and ultra-wide molecular sieving capability with size-dependent COF layers for fast organic solvent nanofiltration

Four covalent organic framework (COF) layers with different alkyl side chains are used to create thin film composite (TFC) membranes via the improved unidirectional diffusion synthetic (UDS) technique. The synthesized membranes consist of polyacrylonitrile (PAN) substrates and TAPB-TPOCx COF (x = 1, 4, 6, and 8) layers, whose pore size and pore environment are tuned by direct integration of variable-length of TPOCx monomers. For organic solvent nanofiltration (OSN), we apply these COF membranes with variable thickness and pore size to test for the sieving ability of various organic pollutant surrogates. With the COF layers' bi-variable thickness and substituent length, the range cut-off molecular weight (330–970 g mol−1) for TAPB-TPOCx COF membranes involves the vast majority of OSN molecular sieving ranges. The COF membranes demonstrate precise molecular sieving capability with higher permeance of polar and nonpolar organic solvents than the state-of-the-art polymeric membranes.

Regio- and stereo-selective halogen-induced cyclization of terminal alkynyl thioethers of 3-phenylquinazoline-4-one

The present work reports the results of the study of the electrophilic heterocyclization of terminal alkynyl thioethers of quinazoline-4-one under the action of halogens. Starting 2-(but-3-in-1-ylthio)-3-phenylquinazolin-4(3H)-one and 2-(pent-4-in-1-ylthio)-3-phenylquinazolin-4(3H)-one were prepared by alkylation of 2-thioxoquinazolin-4-one with butynyl and pentynyl bromide in an alcoholic-alkaline medium, respectively. It was determined that the interaction of 2-(but-3-in-1-ylthio)-3-phenylquinazoline-4(3H)-one with bromine, iodine and iodine bromide is regio- and stereo-selective and leads to the formation of 1-(halogenomethylidene)-6-oxo-5-phenyl-2,3,5,6-tetrahydro-1H-[1,3]thiazino[3,2-a]quinazolinium halides of angular structure as E-isomers. On the contrary, the halogen-induced heterocyclization of 2-(pent-4-in-1-ylthio)-3-phenylquinazolin-4(3H)-one leads to the annelation of thiazepine cycle to quinazoline core with formation of E-1-(bromomethylidene)-7-oxo-6-phenyl-1,2,3,4,6,7-hexahydro-[1,3]thiazepino[3,2-a]quinazolinium tribromide and E-1-(iodomethylidene)-7-oxo-6-phenyl-1,2,3,4,6,7-hexahydro-[1,3]thiazepino[3,2-a]quinazolinium monobromide. It was found that an increase in the carbon length of the terminal alkynyl substituent by one methylene group affects the regioselectivity of the halocyclization process, but does not affect the stereoselectivity.

Synthesis and Additive Manufacturing of Hydrazone-Linked Covalent Organic Framework Aerogels.

Covalent Organic Frameworks (COFs) are crystalline, porous organic materials. Recent studies have demonstrated novel processing strategies for COFs to form adaptable architectures, but these have focused primarily on imine-linked COFs. This work presents a new synthesis and processing route to produce crystalline hydrazone-linked COF gels and aerogels with hierarchical porosity. The method was implemented to produce a series of hydrazone-linked COFs with different alkyl side-chain substituents, achieving control of the hydrophilicity of the final aerogel. Variation in the length of the alkyl substituents yielded materials with controllable form factors that can preferentially adsorb water or nonpolar organic solvents. Additionally, a method for additive manufacturing of hydrazone-linked COFs using hydroxymethylcellulose as a sacrificial additive is presented. This work demonstrates an effective and simple approach to the fabrication of hydrazone COF aerogels and additive manufacturing to produce hydrazone COFs of desired shape.