Reaction Of Ethylenediamine Research Articles

Clean and Efficient Green Protocol of N,N'-Bis(2-(arylazo)-2-(aroyl)vinyl)ethane-1,2-diamines in Aqueous Medium without Catalyst: Synthesis and Photophysical Characterization.

An interesting platform for the construction of novel N,N'-bis(2-(arylazo)-2-(aroyl)vinyl)ethane-1,2-diamines is reported in this work. These bis-arylazo compounds were assembled based on the reaction of ethylenediamine with various 2-arylhydrazono-3-oxopropanals in aqueous conditions under both conventional stirring and microwave conditions at ambient temperature. The factors affecting the optimization conditions were intensively practiced. The structures of the new products were established from their spectroscopic analyses and X-ray single crystals. The photophysical behavior of the bis-arylazo derivatives was examined. The UV-vis spectra showed maximum absorption band in the range of 348-383 nm with molar extinction coefficients ranging from 0.89 × 104 to 4.02 × 104 M-1 cm-1. The highest molar absorptivity coefficient (∼45 × 103 M-1 cm-1) was observed in CHCl3 solvent. The fluorescence properties showed that some compounds were interesting fluorophore materials with high Stokes shifts. The photoluminescence study of some compounds was promising, with maximal emission peaks ranging between 417-436 nm.

SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF 16-MEMBERED SCHIFF BASE MACROCYCLE

Novel tetraazamacrocyclic complexes of Cu(II), Co(II), Ni(II) and Zn(II) has been synthesized from the reaction of ethylenediamine with Meldrums acid and divalent metal ions using solid-supported perchloric acid (HClO4 -SiO2 ) as a catalyst. The complexes were characterized by IR, 1HNMR, EPR spectra, magnetic moments, conductance, thermal analysis and powder XRD analysis. The antimicrobial studies of these complexes against Staphylococcus typhi, Staphylococcus aurieus, Escherichia coli, Bacillus subtilis species by Minimum Inhibitory Concentration (MIC) method revealed that these complexes possess potent antibacterial activity.

Synthesis and Structural Characterization of 16-Membered Schiff Base Macrocycles

Novel tetraazamacrocyclic complexes of Cu(II), Co(II), Ni(II) and Zn(II) has been synthesized from the reaction of ethylenediamine with Meldrums acid and divalent metal ions using solid-supported perchloric acid (HClO4-SiO2) as a catalyst. The complexes were characterized by IR, 1HNMR, EPR spectra, magnetic moments, conductance, thermal analysis (TGA and DTA), and powder X-ray analysis (XRD). The antimicrobial studies of these complexes against Staphylococcus typhi, Staphylococcus aurieus, Escherichia coli, Bacillus subtilis species by Minimum Inhibitory Concentration (MIC) method revealed that these complexes possess potent antibacterial activity.

Synthesis, Spectral Investigations, Biological Potential and Molecular Docking Study of Novel Schiff Base and its Transition Metal Complexes

Aim: The present study was designed to synthesize novel Schiff bases and their metal complexes with promising antimicrobial and anti-angiogenic potential. Background: Currently, drug resistance has been seen in a diverse range of microbes, which is considered a major threat to widespread infectious diseases. Therefore, it is essential to investigate novel therapeutic molecules with broad-spectrum activities. Method: The novel Schiff base ligands were synthesized by using a condensation reaction of ethylenediamine with p-chloroacetanilide and p-bromoactanilide. Fe(III), Ni(II), Mn(II), and Co(II) metal complexes were prepared by refluxing the ligand with respective metal chloride salts in a 2:1 molar ratio. Results: Structures of the synthesized compounds were characterized by IR, 1H NMR, UV-VIS, and mass spectrometry. Anti-microbial activities of all the synthesized compounds were determined against bacterial strains (S. aureus and K. pneumoniae) and fungal strains (A. niger and Trichophyton rubrum) by using the well plate diffusion method. DNA photo-cleavage and anti-angiogenic properties were evaluated by gel electrophoresis and CAM assay, respectively. Molecular docking studies were performed to analyze the binding interactions of synthesized compounds with topoisomerase II alpha. Conclusion: The present preliminary efforts may be helpful to design novel drugs with therapeutic potential.

Cytotoxic Activity of Piperazin-2-One-Based Structures: Cyclic Imines, Lactams, Aminophosphonates, and Their Derivatives.

N-Heterocycles are considered as desirable scaffolds for the development of novel lead compounds for anticancer drug research. Among them, phosphorus-containing amino-derivatives play a crucial role. A series of imines and products of their further reactions with P-nucleophiles were obtained starting from vicinal bisamines. Reaction of ethylenediamine and α-carbonyl esters yielded in novel unexpected products, which structures were confirmed by crystallographic measurements. The cytotoxic activity evaluation was done on a variety of cell lines including HUH7, AKH12, DAOY, UW228-2, D283, D425, and U251. Human umbilical vein endothelial cells (HUVECs) were used as control. Two of the tested compounds, bearing TADDOL-derived, and trifluoromethyl substituents showed a significant effect on cell viability, though comparable to nonmalignant cells.

Unexpected Coordination Modes of Bisphosphoramides with Lanthanum(III) and Thorium(IV) Salts: Synthesis, Structural Characterization, Stability, and Extraction Studies

AbstractA series of bisphosphoramides of the type R2P(O)NHCH2CH2NHP(O)R2 (L) (where R=n‐butyl, n‐hexyl, n‐octyl, ethoxy, phenyl) is synthesized in two‐steps by Atherton‐Todd reaction of ethylenediamine and H‐phosphonate derived from the reaction of diethylphosphite and the Grignard reagent. These ligands were employed in the preparation of La(III) and Th(IV)complexes of the general type [LaCl3(L)2]n and [Th(NO3)4Th(IV)2]. Notably, La(III) complexes of bisphosphoramides are found as infinite coordination polymers with bridging phosphine oxide ligands in an intermolecular fashion. In contrast, Th(IV) complexes are formed with two chelating bisphosphoramide ligands around the metal center intramolecularly. All these ligands and the corresponding metal complexes are characterized by spectroscopic and analytical data. The single‐crystal X‐ray analyses of lanthanum and thorium complexes each confirm the coordination modes. Further, these ligands were evaluated to check the extraction behavior with Am(III), U(VI), Th(IV), and Pu(IV) as a function of nitric acid concentration.

Synthesis, characterization, thermal stability, electrochemical behavior, and antioxidant activity of new oxovanadium(iv) and iron(ii) tetradentate Schiff base complexes

Two new tetradentate oxovanadium(IV) and iron(II) Schiff base complexes have been prepared by the interaction of vanadyl(IV) and iron(III) acetylacetonate with the ligand obtained from the reaction of ethylenediamine and 5′-(N-methyl-N-phenylaminomethyl)-2′-hydroxyacetophenone in methanol. These complexes have been characterized by means of different spectroscopic techniques such as UV–visible, FT-IR, mass spectrometry, and elemental analysis. In addition, thermogravimetric (TG) and differential thermogavemetric analysis (DTG) have been utilized to investigate the thermal stability of these complexes. Results showed that both Schiff base complexes decompose in five consecutive stages, and a mechanism has been proposed for each stage of thermal decomposition. Thermogravimetric analysis has been carried out using four different heating rates of 5, 10, 15, and 20 °C min−1, and the kinetic parameters of these complexes have been calculated using the Kissinger method. Cyclic voltammetry has been employed to examine the electrochemical behavior of the two synthesized complexes in dimethyl sulfoxide (DMSO) at a glassy carbon electrode. Each of these complexes displayed one quasi-reversible single electron transfer peak near 0.255 V vs. saturated calomel electrode (SCE) for the V(V)–V(IV) couple and near −0.690 V vs. SCE for the Fe(III)–Fe(II) redox couples, respectively. Finally, the antioxidant activity of the newly prepared complexes has been investigated using the 2,2-diphenyl-1-picrylhydrazyle (DPPH) free radical scavenging assay. Results revealed that the oxovanadium Schiff base complex exhibits good antioxidant activity.

One-pot Multicomponent Synthesis of pyrrolo[1,2-d][1,4]benzoxazines and pyrrolo[1, 2-a]pyrazines in Water Catalyzed by Fe3O4@SiO2@L-Arginine-SA Magnetic Nanoparticles.

Synthesis of pyrrolo[1,2-d][1,4]benzoxazines and pyrrolo[1,2-a]pyrazines using magnetic nanoparticles. One-pot, three component reaction for the synthesis of pyrrolo[1,2-d][1,4]benzoxazines and pyrrolo[1,2-a]pyrazines is reported. For the synthesis of pyrrolo[1,2-d][1,4]benzoxazines use of 2- aminophenols, dialkylacetylenedicarboxylates and β -nitrostyrene derivatives and Pyrrolo[1,2-a]pyrazines synthesized from reaction of ethylenediamine, dialkylacetylenedicarboxylates and β-nitrostyrene derivatives is discussed. 2-aminophenol (0.5 mmol) and dimethylacetylenedicarboxylate (0.5 mmol) in water (3 ml) were stirred at room temperature for 10 min. Then, β-nitrostyrene (0.5 mmol) and Fe3O4@SiO2@LArginine- SA MNPs (0.07 g) were added and the mixture was refluxed for 5 h. After completion of the reaction, the mixture was cooled to room temperature and the catalyst was separated with external magnet and product extracted with dichloromethane. More purification of products was performed by column chromatography (nhexane/ ethyl acetate 4:1). Ethylenediamine (0.6 mmol) was added to dialkylacetylenedicarboxylate (0.6 mmol) in 3 ml water and was stirred for 10 min at room temperature. Later, β -nitrostyrene (0.5 mmol) and Fe3O4@SiO2@L-Arginine-SA MNPs (0.06 g) were added to mixture reaction and refluxed for 3 h. After completion, the mixture reaction was cooled to room temperature and the catalyst was separated by an external magnet. Then, the product was extracted with dichloromethane. For more purification column chromatography was used (n-hexane/ethylacetate 1:1). In this research, we have synthesized new derivatives of pyrrolo[1,2- d][1.4]benzoxazines and pyrrolo[1,2-a]pyrazines in green conditions consisting of use of water as a green solvent and magnetic nanoparticles. In this research, we have synthesized new derivatives of pyrrolo[1,2-d][1.4]benzoxazines and pyrrolo[1,2-a]pyrazines in green conditions consisting of use of water as a green solvent and magnetic nanoparticles which were easily separated from mixture with an external magnet and had the capability to be recovered and reused. Also, in this work, the yield was good and the time of reactions was low compared with prior research.

Amino-functional carbon quantum dots as a rational nanosensor for Cu2+

Intracellular copper (Cu2+) plays a crucial role in regulation of physiological and biological processes. Nevertheless, excessive copper from bioaccumulation may cause potential risk to human body. Hence, effective and sensitive identification system is essential to avoid excessive intake of copper. A novel highly sensitive fluorescent probe has been designed for detecting copper ion. Carbon dots was synthesized by citric acid and poly(amido amine) dendrimers (2G-PAMAM) as carbon and nitrogen source, respectively. Amino-functionalized carbon dots (NH2-CDs) was obtained by further modification by methyl acrylate and ethylenediamine reaction, which illustrated high quantum yield of 20% and small particle size of 25 nm. The functionalized NH2-CDs offered a rapid, sensitive and selective recognition of Cu2+ with a detection limit of 5 nM and a dynamic linear range from 0.005 to 600 μM. As for practical application, the nanosensor illustrated good cell permeability and low cytotoxicity, and thus successfully applied for fluorescence imaging and biosensing of trace Cu2+ in MCF-7 and HepG-2 cells, which suggested the potential biological application in disease diagnosis.

Synthesis and Characterization of Schiff Base Complexes of Cu(II), Co(II) and Cd(II) Derived from Ethylenediamine and Benzaldehyde Derivatives

Metal complexes of Cu(II), Co(II) and Cd(II) have been synthesized using two new Schiff base ligands, N,N'-bis(4-chlorobenzylidene)ethane-1,2-diamine (L1) and N,N'-bis(3-nitrobenzylidene) ethane-1,2-diamine (L2). The Schiff bases were prepared from the condensation reaction of ethylenediamine with benzaldehyde derivatives (4-chlorobenzaldehyde and 3-nitrobenzaldehyde). The complexes have been characterized by elemental analysis, conductivity measurements, UV-visible, FT-IR and magnetic susceptibility measurements. The magnetic susceptibility measurements and UV-visible spectral data revealed that the geometry of Cu(II) and Co(II) complexes are square planar, whereas the geometry of Cd(II) complex is tetrahedral. The molar conductance data showed that the complexes are non-electrolytic in nature. The complexes were screened for antibacterial activities against four human pathogenic bacteria viz. Escherichia coli, Shigella boydii, Bacillus cereus and Staphylococcus aureus. The results indicate that Cd(II) complex of ligand (L1) has higher antibacterial activity compared to the free ligands, but less than the standard drug, kanamycine. This suggests that the metal ion plays an important role in the antibacterial activities of complexes.

Ag Nanoparticles Stabilized on Cyclodextrin Polymer Decorated with Multi-Nitrogen Atom Containing Polymer: An Efficient Catalyst for the Synthesis of Xanthenes.

In attempt to broaden the use of cyclodextrin polymer for catalytic purposes, a novel covalent hybrid system was prepared through growth of multi-nitrogen atom containing polymer (PMelamine) derived from reaction of ethylenediamine and 2,4,6-trichloro-1,3,5-triazine on the functionalized cyclodextrin polymer (CDNS). The resulting hybrid system was then utilized as a catalyst support for the immobilization of silver nanoparticles through using Cuscuta epithymum extract as a naturally-derived reducing agent. The catalytic activity of the catalyst, Ag@CDNS-N/PMelamine, for the synthesis of xanthenes through reaction of aldehydes and dimedone in aqueous media was examined. The results showed high catalytic activity and recyclability of the catalyst. It was believed that cyclodextrin in the backbone of the catalyst could act both as a capping agent for Ag nanoparticles and phase transfer agent to bring the hydrophobic substrates in the vicinity of the catalytic active sites and accelerate the reaction rate. Multi-nitrogen atoms on the polymer, on the other hand, could improve the Ag NPs anchoring and suppress their leaching.

The Reaction of Ethylenediamine with 1,4‐Bis(trimethylsilyl)butadiyne and the Role of Water: A Qualitative Method for the Determination of Water Impurities in Ethylenediamine

Alkenylation of [Ge9]4– and formation of the vinylated species [Ge9(CH=CH2)n](4–n)– proceed only in ethylenediamine (en) as a solvent. Variation of the alkyne leads to coupling products between the alkyne and en. Herein, we investigated the coupling reactions between 1,4‐bis(trimethylsilyl)butadiyne and en and showed that a water impurity in en plays a decisive role in the outcome of the reaction. NMR spectroscopic investigations revealed that 1‐trimethylsilyl‐7‐amino‐5‐aza‐hepta‐3‐en‐1‐yne is formed by addition of en at 1,4‐bis(trimethylsilyl)butadiyne. Addition of another amino‐functionality of en giving both the cyclization product and 1,9‐di‐amino‐4‐methyl‐3,7‐di‐aza‐nonadiene is only possible in presence of water. 1,9‐Di‐amino‐4‐methyl‐3,7‐di‐aza‐nonadiene is also formed by the reaction of deprotonated en with 1‐trimethylsilyl‐7‐amino‐5‐aza‐hepta‐3‐en‐1‐yne. Based on these results, we developed a simple method to detect water in en, supported by 1H NMR spectroscopy. The finding that 1,9‐di‐amino‐4‐methyl‐3,7‐di‐aza‐nonadiene is also formed by reaction of 1‐trimethylsilyl‐7‐amino‐5‐aza‐hepta‐3‐en‐1‐yne with deprotonated en was exploited to indirectly proof the deprotonation of en upon the nucleophilic reaction of [Ge9]4– with alkynes in the solvent en.

Ionic metallo‐Schiff base polymers of VO2+, Zn2+ and Cu2+: Synthesis, characterization and solid‐state conductivity

The viologen‐type dialdehyde of [N,N′‐bis(methylsalicylaldehyde)‐4,4′‐bipyridinium] dichloride (DA) was synthesized by reacting 5‐chloromethylsalicylaldehyde and 4,4′‐bipyridine. Then a new polymeric Schiff base ligand (PSBL) was synthesized by the condensation reaction of ethylenediamine and DA in methanol under reflux conditions. Afterwards, new ionic metallo‐Schiff base polymers (IMSPs) were synthesized by reacting PSBL with VO(acac)2, ZnCl2 and CuCl2 via coordination chelation. DA, PSBL and IMSPs were characterized using various analytical methods and spectral techniques. The solid‐state electrical conductivities of PSBL and IMSPs were studied. The electrical conductivity of these polymers at 300 K ranged from 1.30 × 10−5 to 4.52 × 10−10 Ω−1 m−1, which means they are potential organic and metallo‐organic semiconductors.

Transition metal complexes of N1,N1,N2,N2-tetrakis(diphenylphosphaneyl)-ethane-1,2-diamine [(Ph2P)2NCH2CH2N(PPh2)2

The reaction of ethylenediamine with four equivalents of chlorodiphenylphosphine in the presence of a base produced tetraphosphine [(Ph2P)2NCH2CH2N(PPh2)2] (1) which on further treatment with H2O2 (30% aq.) gave tetrakis(phosphineoxide) [(Ph2P(O))2NCH2CH2N((O)PPh2)2] (2). Treatment of 1 with two equivalents of Mo0, W0, NiII and RuII precursors yielded [{Mo(CO)4}2(Ph2P)2NCH2CH2N(PPh2)2] (3), [{W(CO)4}2(Ph2P)2NCH2CH2N(PPh2)2] (4) [{NiCl2}2(Ph2P)2NCH2CH2N(PPh2)2] (5) and [{Ru(η5-C5H5)PPh3}2(Ph2P)2NCH2CH2N(PPh2)2][Cl]2 (6). The reactions of 1 with [Cu(NCCH3)4][BF4] and [AuCl(SMe2)] resulted in the formation of di- and tetranuclear complexes [{Cu(NCCH3)2}2(Ph2P)2NCH2CH2N(PPh2)2][BF4]2 (7) and [{Au2Cl2}2(Ph2P)2NCH2CH2N(PPh2)2] (8), respectively. All the compounds were characterized by various spectroscopic methods and compounds 1–6 and 8 were characterized by single crystal X-ray diffraction analysis.

Effect of Antioxidants on Stability of Aqueous Solutions of Selenurea and on Properties of Lead Selenide Films Obtained with These Antioxidants

Spectrophotometric method was used to study the kinetics of the process in which aqueous solutions of selenurea of various compositions are oxidized. Significant differences between the stabilities of selenurea solutions were revealed in relation to the selenurea concentration and also to the acidity, or alkalinity of a medium. It was shown that the stability of selenurea solutions is affected by additives of various antioxidants: sodium sulfite Na2SO3, ascorbic acid C6H8O6, hydroxylamine chloride NH2OH·HCl, hydrazine hydrate N2H4·H2O, and tin chloride SnCl2·2H2O. It was found that using a 1 : 1 mixture of antioxidants Na2SO3 and C6H8O6 substantially raises their antioxidant activity and stabilizes the aqueous solutions of selenurea during up to five days. A hydro-chemical precipitation in the acetate—ethylenediamine reaction system in the presence of the antioxidants under study was used to obtain lead selenide films of stoichiometric composition with thicknesses of 230‒670 nm. With the Na2SO3 + C6H8O6, Na2SO3, C6H8O6, and SnCl2 antioxidants used to stabilize selenurea solutions, a tendency is observed toward a decrease in the lattice constants of PbSe films from 6.1531 ± 0.0003 to 6.1367 ± 0.0002 A, an increase in the share of nanosize particles, and rise in the PbSe energy gap width from 0.78 to 1.0 e V.

Features of the Formation of Thin Films of Supersaturated Cd x Pb1–xS Solid Solutions by Chemical Bath Deposition

Thin nanostructured films of lead sulfide-based CdxPb1–xS solid solutions, strongly supersaturated with respect to the substituting component, were prepared by hydrochemical deposition from ammonia-citrate, ethylenediamine-citrate, and ethylenediamine reaction mixtures onto glass-ceramic substrates. The structure, composition, and morphology of the resulting films were examined. An interesting feature of the synthesis was revealed, a distinct correlation between the linear dimensions of the crystallites constituting the films and the cadmium sulfide content therein: the higher cadmium sulfide content, the smaller were the crystallites.

Copolymerization of transition metal salen complexes and conversion into metal nanoparticles supported on hierarchically porous carbon monoliths: a one pot synthesis

Described is the synthesis of metal (Ni, Cr, and Mn) doped macro/mesoporous carbon monoliths by co-polymerization of transition metal complexes with resorcinol/formaldehyde and subsequent pyrolysis. Two salen ligands were synthesized via reaction of ethylene diamine (EDA) and 1,6-diaminohexane (DAH) with 2,4-dihydroxybenzaldehyde to give 4,4′-((1E,1′E)-(ethane-1,2-diylbis(azanylylidene))bis(methanylylidene))bis(benzene-1,3-diol) (=E-salen) and 4,4′-((1E,1′E)-(hexane-1,6-diylbis(azanylylidene))bis(methanylylidene))bis(benzene-1,3-diol) (=D-salen). Their metal salen complexes were prepared. All the samples pyrolyzed at 500 °C had macro and mesopores with a specific surface area ranging from 250–500 m2/g. However, the surface area and porosity of the samples decreased dramatically for the metal containing samples pyrolyzed at 800 °C. This is suggested to result from incomplete co-polymerization of the metal salen complexes. The extent of graphitization determined from Raman increased with the pyrolysis temperature. The electrical conductivity was found to increase with the pyrolysis temperature, and followed the trend Ni > Mn > Cr. The M-E-salen containing samples had significantly lower conductivity than their D-salen counterparts.

Copper(II) complex as a precursor for formation of cyano-bridged pentanuclear FeIII-CuII bimetallic assembly: Synthesis, characterization, crystal structure and antibacterial activity

[CuL(ClO4)2] (1) (L = 3,10-diisobutyl-1,3,5,8,10,12-hexaazacyclotetradecane) was synthesized by condensation reaction of ethylenediamine, formaldehyde and iso-butylamine in absolute ethanol. Characterization of 1 utilized various spectroscopic techniques, viz. elemental analysis, electrospray ionization-mass spectrometry (ESI-MS), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), diffuse reflectance spectroscopy (DRS) and thermogravimetric analysis (TGA). Based on these techniques, the structure of 1 was proposed as Cu(II) ion occupying octahedral geometry with four secondary amine nitrogens of the hexaazamacrocyclic ligand and two perchlorato anions. 1 was used as a precursor in the preparation of cyano-bridged bimetallic compound, [CuL]3[Fe(CN)6]2⋅5H2O (2), by reaction with K3[Fe(CN)6] in aqueous solution. Single-crystal X-ray analysis indicated that 2 crystallized in the monoclinic system with space group P21/n. The structure of 2 consisted of cyano-bridged FeIII-Cu II pentanuclear molecules having two [Fe(CN)6] 3− anions connected to three cis-[CuL] 2+ cations via two cis-cyanide ligands from each ferrate unit. In each of pentanuclear unit, the central [CuL] 2+ cation exhibited a distorted octahedral geometry while the other two units exhibited a distorted square pyramidal geometry. The room temperature magnetic moments of both complexes were measured to be 1.92 B.M. for 1 and 5.61 B.M. for 2. The in vitro antibacterial activity of 1 against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853 strains were studied and compared with standard drugs, which showed moderate antibacterial activity compared with Penicillin and Gentamicin. A copper mononuclear complex was synthesized, characterized with various techniques, and used as a precursor to synthesize a pentanuclear (FeIII-CuII) complex. The Xray structure of the new pentanuclear complex is reported. The precursor copper complex exhibited moderate antibacterial activity.

Structural, thermal, optical and nonlinear optical properties of ethylenediaminium picrate single crystals

A new organic optical limiting material, ethylenediaminium picrate (EDAPA) was synthesized through acid base reaction and grown as single crystals by solvent evaporation method. Single crystal XRD analysis showed that EDAPA crystallizes in orthorhombic system with Cmca as space group. The formation of charge transfer complex during the reaction of ethylenediamine and picric acid was strongly evident through the recorded Fourier Transform Infra Red (FTIR), Raman and Nuclear Magnetic Resonance (NMR) spectrum. Thermal (TG–DTA and DSC) curves indicated that the material possesses high thermal stability with decomposition temperature at 243°C. Optical (UV–Visible-NIR) analysis showed that the grown crystal was found to be transparent in the entire visible and NIR region. Z-scan studies with intense short pulse (532nm, 5ns, 100µJ) excitations, revealed that EDAPA exhibited two photon absorption behaviour and the nonlinear absorption coefficient was found to be two orders of magnitude higher than some of the known optical limiter like Cu nano glasses. EDAPA exhibited a strong optical limiting action with low limiting threshold which make them a potential candidate for eye and photosensitive component protection against intense short pulse lasers.

Preparation and characterization of microcapsules containing industrially important reactive water-soluble polyamine

Polyurea microcapsules containing water-soluble reactive polyamine, namely, polyaziridine (A33), were prepared by interfacial polymerization technique in non-aqueous medium, wherein (i) A33 was encapsulated for the first time as a neat amine without forming its salt or adduct and (ii) microcapsules formed were without any deleterious effect on A33. A systematic study was conducted by preparing microcapsules with different polyurea wall architectures. Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopic analysis of extracted A33 from microcapsules do not show any structural changes during microencapsulation. A titration method was developed to analyze the amount of encapsulated A33 quantitatively. Polyurea microcapsules obtained from reaction of ethylene diamine (E) and isophorone diisocyanate (I) monomers have shown better properties such as encapsulation efficiency and extent of agglomeration. Significant reduction in the size was observed when microcapsules of EI wall material were prepared by homogenizing the initial emulsion of A33 in paraffin oil. The process described in this paper for the preparation of microcapsules is cost-effective and industrially viable, which can find applications in agrochemicals, coatings, self-healing composites, etc.