Aliphatic Diamines Research Articles

Three-Component Synthesis of 1-Substituted 5-Aminotetrazoles Promoted by Bismuth Nitrate.

A nontoxic bismuth-promoted multicomponent synthesis of 5-aminotetrazoles and bistetrazoles is reported. The reaction of phenyl isothiocyanate, NaN3, and amine (primary aliphatic, aromatic, and aliphatic diamine) promoted by Bi(NO3)3·5H2O under microwave heating affords good yields, short reaction times, simple workup, and purification without column chromatography. A set of diagnostic 1H NMR signals was identified as a guide for quickly elucidating the exclusive (or main) regioisomer formed, with the stronger electron donor group located at heterocyclic nitrogen 1. This regioselectivity is strongly dependent on the electronic density of the amine. It is opposite to that obtained by several thiourea desulfurization methods promoted by thiophilic metals and metal-free protocols.

PI-SiO2 aerogel as a versatile high transparent material for photothermal cooperative management

Effectively insulating against excessive heat generated by sunlight while also avoiding harmful ultraviolet (UV) and maintaining suitable levels of visible light transparency is vital for minimizing energy consumption and optimizing sunlight utilization. To address the challenge of photothermal collaborative management, the PI consisted of high fluorinated dianhydride and aliphatic diamine was used to effectively improve the performance of SiO2 aerogels. The resulting PI-SiO2 aerogels retain the characteristics of SiO2 aerogels, such as low density, high transparency between 82∼89 %, and excellent thermal insulation properties with an ultralow thermal conductivity range from 0.023 W/(m.K) to 0.028 W/(m.K). Meanwhile, the coarsened skeleton of aerogels can withstand the extreme temperature difference between −196 ℃ and 200 ℃ without brittle fracture and yellowing. In addition, PI-SiO2 aerogels exhibit the capability to absorb a significant proportion of UV light within the 200–400 nm, offering distinct advantages in transparent thermal insulation materials. The multifunctional PI-SiO2 aerogels can be used as candidate materials in the fields of architecture, automobile, electronics, solar energy and aerospace.

Repurposing antiparasitic N,N'-aliphatic diamine derivatives as promising antimycobacterial agents.

In previous studies, we demonstrated the potent activity of a library of 25 N,N'-disubstituted diamines (NNDDA) toward Trypanosomatid and Apicomplexa parasites. Considering the structure similarity between this collection and SQ109, an antituberculosis compound, and its compelling antiparasitic properties, we aimed to repurpose this library for tuberculosis treatment. We assayed this collection against Mycobacterium tuberculosis H37Rv and M. avium, obtaining several compounds with MIC values below 10 µM. The most active analogs were also evaluated against M. smegmatis, a non-pathogenic species, and the non-tuberculosis mycobacteria M. abscessus, M. kansasii, and M. fortuitum. 3c stands out as the lead mycobacterial compound of the collection, with potent activity against M. tuberculosis (minimal inhibitory concentration [MIC] = 3.4 µM) and moderate activity against M. smegmatis, M. kansasii, and M. fortuitum (all with MIC values of 26.8 µM). To unravel the mechanism of action, we employed the web-based platform Polypharmacology Browser 2 (PPB2), obtaining carbonic anhydrases as potential drug targets. Nevertheless, none of the compounds displayed experimental inhibition. In summary, our study confirms the validity of the repurposing approach and underscores the antimycobacterial potential of NNDDA compounds, especially the analog 3c, setting a stepping stone for further studies.

Synthesis of Inherently Chiral Homo-heteracalixaromatics.

There is a resurgence of research interest in inherently chiral calixarenes and heteracalixaromatics. However, the examples of macrocyclic ring-expanded homocalixarenes and heterocalixaromatics of inherent chirality are not known. Here we report an efficient method to construct inherently chiral N2,O2-linked homo-heteracalixaromatics from reductive amination reactions between bis-aldehydes and aliphatic diamines. Examples of post-macrocyclization derivatization were also demonstrated. Enantiomers were obtained from resolution and did not undergo racemization at an elevated temperature. This study provides a new strategy to design novel and functional inherently chiral macrocycles that have potential applications in supramolecular chemistry.

A molecular design strategy to develop all‐organic crosslinked polyetherimide film with high discharged energy density at 150°C

AbstractMiniaturization and lightweight of power systems urgently ask for polymer dielectrics with high discharged energy density at 150°C. Herein, a molecular design strategy is built to prepare new crosslinkable polyetherimide films (PEIDx, x is the molar ratio of dianhydride to amines) through simultaneously improving the polarization degree and reducing the residual polarization. Thermal, mechanical, and dielectric properties of PEIDx improve as x increases. PEID0.92 shows the best integrated performances, especially its discharged energy density (5.46 J cm−3, at 10 Hz and 454 MV m−1) is higher than those of reported polymer dielectrics with discharged energy storage at 150°C, and its charge–discharge efficiency is 80.14%. The outstanding energy storage performance of PEID0.92 is attributed to its unique molecular structure. Specifically, the use of nonplanar and low‐alkaline aliphatic cyclic diamine effectively improves the polarization degree of macromolecules; while the crosslinking of alkynyl groups limits the macromolecular movement, thus ensuring high heat resistance and low residual polarization.

Zn-containing ionic liquids as effective catalysts for the condensation of camphor with diamines

The study is dedicated to the investigation of the catalytic activity of zinc carboxylates in the condensation reaction of camphor with aliphatic diamines. The reaction of camphor with 1,6-hexanediamine was selected as the model system. The research demonstrated that the reaction does not proceed without a catalyst, while the use of zinc carboxylates as catalysts leads to a higher conversion and selectivity compared to the classical catalyst for this reaction, Et2O∙BF3. The best results were achieved using zinc 2-ethylhexanoate, which provided an 88.4 % conversion of camphor and a 76.9 % selectivity for the formation of diimine. It was established that the catalytic activity of zinc carboxylates in the condensation reaction of camphor with diamines is related to the structure of the acid residue of the salt. Based on the obtained data, a reaction mechanism was proposed, associated with the formation of a complex between the zinc carboxylate and the initial amine, which is confirmed by FTIR and UV–vis spectroscopic data.

Structure-Glass Transition Relationships in Non-Isocyanate Polyhydroxyurethanes.

The molecular dynamics, with an emphasis on the calorimetric and dynamic glass transitions, of non-isocyanate polyhydroxyurethanes (PHUs) produced by the equimolar polyaddition of polyether-based dicyclic carbonates (P-CCs) and various short diamines was studied. The diamine component consisted of a short aliphatic diamine (1,4-diaminobutane, DAB) and a more complex 'characteristic' diamine. The study was conducted to investigate (i) the chemical structure of the characteristic amine, (ii) its molar ratio, and (iii) the structure and molar mass of the P-CC. Infrared spectroscopy, differential scanning calorimetry, and broadband dielectric spectroscopy were employed. The P-CC, constituting the bulk of the systems, was the most crucial component for the glass transition. The characteristic amine influenced the glass transition as a result of its bulky structure, but also presumably as a result of the introduction of free volume and the formation of hydrogen bonds. The dynamic glass transition (α relaxation) trace in the Arrhenius plots showed a subtle change at a certain temperature that merits further study in the future. The charge mobility was fully coupled with the molecular mobility, as evidenced by dc conductivity being directly proportional to the characteristic frequency of α relaxation. The fluctuation in carbonyl units (β relaxation) was mildly affected by changes in their immediate environment.

Synthesis and properties of new polyimide foams from foaming compositions with flexible segments of aliphatic diamine

AbstractNew foaming prepolymer compositions based on 4,4′‐oxydiphthalic anhydride, 4,4′‐diaminodiphenyl ether, 1,6‐hexamethylenediamine (HMDA), and a surfactant were synthesized. Polyimide (PI) foams containing from 0 to 40 mol% HMDA were prepared. The possibility of controlling the pore sizes in a foam material by selecting different fractions (250–400 μm) of particles of the powdered foam composition for heat treatment was shown. Scanning electron microscopy studies of morphology of the synthesized PI foams (PIFs) showed that all foams exhibited open cellular structures with pore diameters ranging from 50 to 500 μm. The influence of the components of the foaming composition (surfactant and aliphatic diamine) on the structure, thermal, and mechanical properties of the resulting PIFs was traced. The samples of PIFs containing 20% and 30% HMDA were elastic (the corresponding stress–strain curves were almost linear up to the 30% deformation) and able to restore their shape after removing the load. The resulting foams exhibited high thermal stability (the onset of weight loss was observed in the 470–500°C range). It was revealed that the synthesized PIF compositions were incombustible in an open flame. Due to their high heat resistance and nonflammability, the obtained PIFs can be used for thermal insulation applications in the aerospace, transport, construction, and microelectronics industries.Highlights New, lightweight, flexible, and nonflammable PIFs have been synthesized. The HMDA additive imparts elasticity to PIFs. The introduction of a surfactant (KT‐6) makes the PIF homogeneous.

The relationship between the structure of stearic acid diamide lubricants and the lubrication properties in acrylonitrile-butadiene-styrene resins

Although amide lubricants are commonly used as lubricants for acrylonitrile-butadiene-styrene (ABS) resins, the relationship between their structure and lubricating properties remains unclear. In this paper, a series of stearic acid diamide lubricants for ABS resins were synthesized through an amidation reaction with the stearic acid and aliphatic diamines. The chemical structure was characterized by FTIR and 1H NMR. A detailed evaluation of the lubrication effect of the lubricant was carried out by dynamic mechanical analysis, rotational rheometry, contact angle measurements, and so on. The results showed that the complex viscosity, glass transition temperature and diamine's alkyl chain length of stearic acid diamides were positively correlated, while the elongation at break displayed a negative correlation. Compared to ethylenediamine bis stearate acid (EBA), 1,8-diaminooctane bis stearate acid (OBA) exhibited a 37.8 % increase in the complex viscosity at 0.1 rad/s, along with a 4.6 % rise in the glass transition temperature. It was indicated that the lubrication effect of stearic acid diamides deteriorated with the increase of the alkyl chain lengths of diamines. The lubrication mechanism was further validated by molecular dynamics simulations. As the alkyl chain lengths of diamines increased, the mean square displacement and interaction energy of the system exhibited a tendency to become lower and higher, respectively. This meant that the longer alkyl chains of the diamines in the lubricants were not advantageous to the free mobility of the matrix molecular chains. These findings provided insightful guidance for the sensible design of lubricants for ABS resins.

Coordination Polymer Based on a Triangular Carboxylate Core {Fe(μ3-O)(μ-O2CR)6} and an Aliphatic Diamine.

Interaction of the pre-organized complex of iron(II) trimethylacetate and 1,10-phenanthroline (phen) [Fe2(piv)4(phen)2] (1) (piv = (Me)3CCO2-)) with 1,6-diaminohexane (dahx) in anhydrous acetonitrile yielded a 1D coordination polymer [Fe3O(piv)6(dahx)1.5]n (2) and an organic salt of pivalic acid (H2dahx)(piv)2 (3). The structure of the obtained compounds was determined by single-crystal X-ray diffraction analysis. The phase purity of the complexes was determined by powder X-ray diffraction analysis. According to the single-crystal X-ray analysis, coordination polymer 2 is formed due to the binding of a triangular carboxylate core {Fe3(μ3-O)(μ-piv)6} with an aliphatic diamine ligand. Thermal behavior was investigated for compounds 1 and 2 in an argon atmosphere.

Synthesis of tribenzo-1,6-diazabicyclo[4.4.4]tetradecane

1,6-Diazabicyclo[4.4.4]tetradecane, which was extensively studied by Alder et al. in the 1970–1980 s, exhibits very interesting redox and protonation properties. We intended to synthesize its benzo analog as an extension of our studies on aza cryptands; however, by following Alder’s synthetic route, we obtained only tricyclo[4.4.4.01,5]tetradecane tribenzo analog. Therefore, the target compound was synthesized from 2,11-diaza[3.3]-o-cyclophane. The proton-template synthesis of the benzo analog was straightforward and clean. The optimized structures of the products were obtained by DFT calculations since crystal structures were not available. The results showed that the NH+ proton of the ammonium salt was biased towards the nitrogen atom on one side. This is in contrast to the internally protonated 1,6-diazabicyclo[4.4.4]tetradecane·H+, in which the proton is located exactly halfway between two N atoms. Thus, the properties of the tribenzo analog is different from those of their parent aliphatic bicyclic diamine, and the basicity is comparable to that of ordinary amines.

Biorenewable vegetable oil based nonisocyanate polyurethanes and nanocomposites; formulation, characterisation, biodegradation, anticorrosion and antifouling coatings

Castor oil cyclic carbonate chosen as sustainable precursor to afford biodegradable NIPU via polyaddition of aliphatic diamine and NIPU nanocomposites by functionalized Fe3O4 via covalent incorporation, used as anticorrosion and antifouling coating.

The highly selective rhodol-based putrescine probe and visual sensors for on-site detection of putrescine in food spoilage

Putrescine (Butane-1,4-diamine) has been regarded as a vital marker of spoiling protein-rich foods, especially meat and seafood. The detection of putrescine in food is considered a convenient and powerful method for evaluating the degree of spoilage of protein-rich foods. Herein, a novel rhodol-based fluorescent probe RSMA (formyl-rhodol Schiff base with methoxyaniline) was developed to detect putrescine. RSMA exhibited excellent linearity (R2 = 0.9912) in the concentration range of 0–45 μM of putrescine with a detection limit as low as 0.45 μM. Although RSMA had moderate responses to some aliphatic diamines, the selectivity of RSMA for putrescine was one of the best reported in the literature so far. Moreover, RSMA was successfully fabricated to solid-state sensors for on-site detection of putrescine in shrimp, that demonstrated its application in monitoring food spoilage.

Advanced Characterization of Pillared Graphene-Based Materials for Supercapacitors

Materials for supercapacitors have to display large surface area to maximize the number of adsorbed ions [1], and they must also possess a hierarchical porosity (Fig. 1) to favour ions diffusion. Graphene-derived materials are studied as they –theoretically- combine all these porosity-related parameters. However experimentally the achieved capacitance (CSP) remains limited because graphene sheets tend to re-aggregate. Our group has selected a method to avoid this issue by creating an expanded graphene structure by bridging and separating the sheets using aliphatic diamine pillars. These assemblies are called Pillared Graphene materials (PGM). Electrochemical results showed that these PGM display higher capacitance than reference non pillared materials [2,3]. However, it was not possible to correlate these storage performances improvements to adsorption active surface area determined with N2 gas sorption (BET), which questions the suitability of this technique for measuring the full porosity of the samples, which is likely to be more accessible in an electrolytic environment. Therefore, to further correlate storage performances of PGM to their structure, structural advanced characterization techniques such as small angle X-ray and neutron scattering (SAXS/SANS) were employed.These methods enable to assess samples porosity at the local scale (~30 to 140nm) as well as the solid phase density. In the frame of this presentation, SAXS/SANS not only have been applied to pristine materials, but also to specifically formulated samples (pellet, electrodes) in order to highlight structural differences arising from synthesis protocol or from molecular pillaring. The ionic charge diffusion and adsorption in specific porosity ranges, analyzed using preliminary Operando scattering techniques, will be evoked. So far the interplay between increased adsorption sites and improved electrochemical performances has only been intuited on the basis of indirect electrochemical studies; the strategy devised herein proposes the use of direct structural techniques to confirm these interpretations.

Monomer ratio‐controlled polyimides with enhanced dielectric properties and thermal stabilities through crosslinking network

AbstractPolyimides (PI) are considered as one of the most used materials for flexible printed circuit board substrates because of their excellent thermal stabilities, outstanding mechanical properties, and great dielectric properties. Dielectric constants (Dk) of common commercial PIs, however, are still above 3.0 (at 10 GHz), which is still substandard for high‐frequency applications. In this study, we develop thermally stable PIs with enhanced dielectric properties by structural design and crosslinking. Stiff aromatic 2,2′‐bis(trifluoromethyl)benzidine (TFMB) and soft aliphatic dimer diamines (DDA, priamine), including priamine 1074 (DDA‐1) and priamine 1071 (DDA‐2), are used as the diamines, and cyclobutanetetracarboxylic dianhydride (CBDA) is used as the dianhydride. By adjusting the ratio of the diamines, a series of PIs (PI‐1–PI‐5) with high thermal stabilities and low‐Dk values are synthesized. Among these PIs, PI‐4 synthesized by diamines with the ratio of TFMB:DDA‐1:DDA‐2 = 85:10:5, possesses relatively good performances. Therefore, PI‐4 is further chosen to be thermally crosslinked. By changing the contents of the crosslinker, triallyl isocyanurate (TAIC), crosslinked PIs (CPIs) are synthesized. The resulting CPIs have a significant improvement in thermal properties, dielectric properties, and mechanical strengths. Especially, for the CPI‐4‐30, in which 30% of TAIC is used, the glass transition temperature (Tg) increases by 20°C, the Dk decreases from 2.62 to 2.41, and the ultimate tensile strength boosts from 91.65 to 115.16 MPa. The CPIs with low Dk and high Tg values may have great potential as substrate materials for broad applications, such as microelectronics and integrated circuit packages.

Efficient selective uptake of mercury ions using inverse vulcanization-synthesized sulfur-rich adsorbents

Mercury abatement from complex environmental sources remains a significant challenge for environmental protection due to the lack of cost-effective sorbents. Sulfur-based adsorbents have been traditionally used for selective uptake of Hg(II) ions, necessitating the creation of effective sulfur adsorption sites. Herein, we propose a sulfur-rich material synthesized method via inverse vulcanization for mercury removal from solutions. Mercury exhibits an affinity for sulfur, and highly active sulfur sites enhance its adsorption efficiency. Inert elemental sulfur can be activated by aliphatic diamine through a ring-opening process, converting sulfur and polyvinyl chloride (PVC) into functional sulfur-rich materials at a mild temperature of 50 °C. The cross-linked structure of PVC enhances the dispersion of active sulfur sites. This sulfur and nitrogen-containing material demonstrates excellent mercury removal capabilities, exhibiting high selectivity even in complex ionic environments, with a maximum adsorption capacity of 309.2 mg/g. Our results highlight the efficiency of this sulfur-rich material as a mercury sorbent. The inverse vulcanization method enables the efficient utilization of two abundant resources, sulfur and waste PVC. This research has been submitted for publication in a scientific journal, and we have provided a concise and polished version for your consideration.

Synthesis and fabrication of lightweight microcellular thermoplastic polyimide foams using supercritical CO2 foaming

Polyimide foams (PIFs) are usually synthesized by solution polymerization, followed by chemical foaming to prepare thermosetting foam. In this research, lightweight microcellular thermoplastic polyimide foams (TPIFs) were fabricated via a novel two-step foaming approach using supercritical carbon dioxide (scCO2) as a blowing agent. The poly(amic acid) (PAA) and polyester ammonium salt (PEAS) precursor solutions were synthesized with pyromellitic dianhydride (PMDA) as dianhydride reagents and polyether amine Jeffamine D230 as aliphatic diamine reagent via blending and solution polymerization, respectively. The solution polymerization process demonstrated a higher molecular weight and superior formability than the blending process. The optimum thermal imidization temperature of 200 °C was optimized via the thermal and rheological property analysis. The cell morphology and mechanical properties of the TPIFs could be turned by varying the saturation time, foaming pressure, and imidization temperature. At a thermal imidization temperature of 200 °C, the TPIFs exhibited a branched structure with a small mean cell diameter (123.78 μm), and a high compressive strength (0.4 MPa) under 10 % strain at high temperature and pressure, which was more than ten times that of the TPIFs with thermal imidization temperature of 130 °C. This research provides a feasible method for producing high volume expansion ratio TPIFs with adjustable microcellular structures and outstanding mechanical properties.

Nickel and cobalt complexes with ferrocenyl Schiff bases: preparation, characterization, and application in ethylene oligomerization

Two aliphatic diamine-bridged ferrocene ligands (C2-Fe-Ligand and C6-Fe-Ligand) were synthesized with aliphatic diamine and formylferrocene, and the corresponding bimetallic active site complexes (Ni-C2-Fe, Co-C2-Fe, and Ni-C6-Fe) were prepared to catalyze ethylene oligomerization. The ligands and the corresponding complexes were characterized by FTIR, 1H NMR, TG, ESI-MS, XRD, and SEM. The SEM results of the ligands confirmed that the length of the bridged group had an influence on the morphology, and an increase in the carbon length led to irregular short rods to the irregular flakes with a large size. The bimetallic complexes catalyzed efficiently ethylene oligomerization with MAO as co-catalyst, and these complexes produced C4 and C6 olefins. Ni-C2-Fe showed higher activity of 6.31 × 104 g·(mol Ni·h)−1 in cyclohexane at Al/Ni molar ratio of 700, temperature of 25 °C, and pressure of 0.5 MPa. Compared with single active site catalysts, the bimetallic active site catalysts had a higher selectivity for C4 olefin because of the competitive insertion of ethylene between different active centers. The modification of the metal center tuned the catalytic performance of the complexes in ethylene oligomerization.

A novel graphene oxide-1,3,4-oxadiazole-2,5-diamine nanomaterial with enhanced bactericide activity

BackgroundThe development of effective nanomaterials is becoming important to safeguard the human health from the bacteria-induced infectious diseases. Among the popular nanomaterials, graphene oxide (GO) owns functional groups and exhibits noticeable benefits which are helpful for biological applications. For raising the antibacterial activity with the reinforcement of the active organic molecules like oxadiazoles, a novel GO-1,3,4-oxadiazole-2,5-diamine (ODA) nanomaterial was prepared and characterized for the first time in our study. MethodsGO-diamine nanomaterials were synthesized by simply reacting GO with ODA or aliphatic diamine in a water bath at room temperature. In an in vitro antimicrobial activity investigation, 5 mg of the nanomaterial was immersed in 20 mL of the Escherichia coli culture in agar media at 37 °C, and the growth of bacteria was evaluated after 24 h. Significant FindingsBy XRD analysis, it was found that the increase in d-spacing after the intercalation of aliphatic diamine into GO layers was close to the molecular length of aliphatic diamine, indicating a perpendicular bridging configuration. Conversely, the aromatic ODA reacted with the oxygenated functionalities on the outer surface of GO layer and a free amine was left behind in the terminal. In the bactericide activity test, a near complete E. coli inhibition was achieved only with GO-ODA, much better than pure ODA (30–60 %) and pristine GO (0–20 %). The pure aliphatic diamines showed some extent of antibacterial activity (20–60 %) due to their natural toxicity, but their GO-aliphatic diamine derivatives demonstrated negligible bactericide activity (0–10 %). Conclusively, this study provides a greener and effective antibacterial material without using any catalyst or organic solvent.

Protonated Organic Diamines as Templates for Layered and Microporous Structures: Synthesis, Crystal Chemistry, and Structural Trends among the Compounds Formed in Aqueous Systems Transition Metal Halide or Nitrate-Diamine-Selenious Acid.

Systematic studies of crystalline compounds formed in aqueous systems containing aliphatic diamines, divalent transition metal halides, and selenious acid resulted in the discovery of a large family of new complex species corresponding to several new structure types. With ethylenediamine (en), layered (enH2)[M(HSeO3)2X2] compounds are the most commonly formed species which constitute a significant contribution to the family of layered hydrogen selenites containing neutral [M(HSeO3)2] (M = Mg, Mn, Co, Ni, Cu, Zn, Cd) 2D building blocks. In contrast to some previous suggestions, piperazine (pip), as well as its homologue N-methylpiperazine, mostly give rise to quite different, sometimes more complex, structures of varied dimensionality while the (pipH2)[M(HSeO3)2X2] compounds are formed only with M = Cu and Cd. In addition, metal-, halide-, or selenium-free by-product species are observed. The SeIV can be present in a multitude of forms, including H2SeO3, HSeO3-, SeO32-, and Se2O52-, reflecting amazing adaptability to the shape of the templating cations.