Aryl Diamines Research Articles

Simulation insights into the spirobifluorene aryl diamine (SBAD-1)/porous organic cage mixed-matrix membranes for organic solvent nanofiltration

Mixed-matrix membranes (MMMs) have emerged as promising materials for organic solvent nanofiltration (OSN) applications due to their potential to synergize polymer and porous nanomaterials. Theoretically understanding the role of nanofillers within MMMs in determining the OSN performance is crucial for the development of new MMMs. In this work, the molecular simulations are performed to investigate the swelling process and OSN performance of the spirobifluorene aryl diamine (SBAD-1)/porous organic cage (POC) MMMs. Three POCs (i.e., CC3, CC5, and CC17) and three organic solvents (i.e., methanol, acetonitrile, and acetone) are studied. The pure SBAD-1 and pure POC membranes are also constructed for comparison. Results show that the attractive interactions between SBAD-1 and POC can restrict the flexibility of polymer chains, and thereby decrease the dilation of polymer matrix and also the porosity of swollen MMM. Based on this, the solvent resistant property and dye rejection would be well enhanced. Moreover, compared with pure SBAD-1 and pure POC membranes, the solvent permeabilities through swollen MMMs are found to drop due to the blockage of POC pores by SBAD-1 chains and the smaller porosity in membrane. This work reveals the pivotal role of interaction between SBAD-1 and POC in the swelling and OSN performance of SBAD-1/POC MMMs, and would provide theoretical support for the development of MMMs for OSN applications.

Cloning, Experession, and Characterization of a Laccase from the White Rot Fungi Pleurotus pulmonarius MPN18

Laccase (EC 1.10.3.2) is an enzyme belonging to the polyphenol oxidase groups, which plays an important role in the oxidation of a wide variety of aromatic substrates, such as lignin, phenol, polyamine, and aryl diamines, as well as a number of other phenolic compounds or inorganic ions in the presence of oxygen. Laccase is widely applied in many different fields, especially in the textile industry, dyeing, and environmental pollution treatment. In this study, we have successfully cloned and expressed cDNA coding for laccase from Pleurotus pulmonarius MPN18 (PpLac). cDNA corresponds to the gene laccase (size 1566 bp) was attached to pET 21a(+) vector and expressed in E. coli BL21, after that the enzyme was purified through HisTrapTM sp 5mL column. The purified PpLac had an activity of 899.8 U, a 74% yield with a purity of 15.2 -fold, and was tested by SDS-PAGE electrophoresis with a molecular weight of Mw = 55 kDa. Enzyme displayed optimal activity at 50 ºC and pH 4.0. Enzyme had optimal activity of 20-40 ºC after 120 min incubation and pH 4 after 6 h incubation. In future, the recombinant enzyme will be characterized for supplementation into enzyme cocktail in the treatment of lignocellulosic material.

Accelerated synthesis of phthalimide derivatives: Intrinsic reactivity of diamines towards phthalic anhydride evaluated by paper spray ionization mass spectrometry.

Paper spray (PS) is a simple and innovative ambient ionization technique for mass spectrometry (MS) analysis. Under PS-MS conditions, chemical reactions, which usually occur slowly on a bulk scale, are accelerated. Moreover, the formation of products and transient species can be easily monitored. In this manuscript, reactions between phthalic anhydride and diamines were conducted and monitored using a PS-MS platform. The reaction products (phthalimides) have many pharmaceutical applications, but their traditional syntheses can take hours under reflux, requiring laborious purification steps. In situ reactions were performed by dropping methanolic solutions of phthalic anhydride and diamines on a triangular paper. The analyses were achieved by positioning the triangle tip in front of the mass spectrometer entrance, whereas a metal clip was attached to the triangle base. After adding methanol to the paper, a high voltage was applied across the metal clip, and the mass spectra were acquired. The intrinsic reactivity of alkyl and aromatic diamines was evaluated. The carbon chain remarkably influenced the reactivity of aliphatic diamines. For aryl diamines, the ortho isomer was the most reactive. Moreover, for aryl amines with electron-withdrawing substituents, no reaction was noticed. Taking advantage of the unique characteristics of PS-MS, it was possible to investigate the intrinsic reactivity of model alkyl (ethylene versus propylene) and aryl (o-phenylene versus m-phenylene and p-phenylene) diamines towards phthalic anhydride. Some crucial parameters that affect the intrinsic reactivity of organic molecules, such as isomerism, intramolecular interaction, and conformation, were easily explored.

Syntheses, characterizations and structures of organometallic tri- and tetra-dentate ferrocenoyl enaminone ligands and their unsymmetrical Schiff base derivatives

Condensation of ferrocenoylacetone with alkyl or aryl diamine (1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminocyclohexane, 1,4-diaminobenzene) afforded three tridentate ferrocenoyl enaminone ligands (Fc–C(O)CHC(CH3)NHR1) (L1: R1 = CH2CH2NH2; L3: R1 = 4-C6H4NH2; L5: R1 = 4-C6H10NH2; Fc = ferrocenyl) and four symmetrical tetradentate ferrocenoyl enaminone ligands [(Fc–C(O)CHC(CH3)NH]2R (L2: R = CH2CH2; L4: R = 4-C6H4; L6: R = 4-C6H10; L8: R = CH2CH2CH2). Of which, L3 was further reacted with appropriate substituted salicylaldehydes to give unsymmetrical Schiff base ligands Fc–C(O)CHC(CH3)NH(4-C6H4)NCH(2-OHAr) (L9: Ar = C6H4; L10: Ar = 5-ClC6H3; L11: Ar = 5-NO2C6H3; L12: Ar = 3,5-Br2C6H2; L13: Ar = 3,5-tBu2C6H2). All new ligands L3∼L6, L8 and L9∼L13 were characterized by 1H NMR, 13C NMR, FT-IR, and UV–Vis spectroscopies along with their electrochemical properties. Moreover, molecular structures of ligands L2∼L4, L8 and L9 have been established by single-crystal X-ray crystallography.

Vibratile Dihydrophenazines with Controllable Luminescence Enabled by Precise Regulation of π-Conjugated Wings

Vibratile Dihydrophenazines with Controllable Luminescence Enabled by Precise Regulation of π-Conjugated Wings

Constructing an ultra-adsorbent based on the porous organic molecules of noria for the highly efficient adsorption of cationic dyes.

A novel Noria-POP-1 material has been successfully synthesized by the simple polymerization of the porous organic molecules of noria and aryl diamines. Noria-POP-1 displayed excellent adsorption capacity for cationic dyes from water with selective removal ability. The adsorption experiments show that Noria-POP-1 displays a remarkable capability to selectively adsorb and separate methylene blue with an adsorption capacity of 2434 mg g−1, which is the highest value obtained so far for porous organic polymers.

A crosslinking alkylation strategy to construct nitrogen-enriched tetraphenylmethane-based porous organic polymers as efficient carbon dioxide and iodine adsorbents

Porous organic polymers (POPs) have received great attention worldwide and become attractive for capture and storage of carbon dioxide (CO2) and radioactive iodine (129I or 131I). Here we present modified tetraphenylmethane (TPM)-based POPs i.e. mPTPMs (synthesized via Buchwald-Hartwig cross-coupling of a tetrakis(4-bromophenyl) methane core and selected aryl diamine linkers, followed by a crosslinking alkylation strategy using diiodomethane as a crosslinker). This new strategy offers mPTPMs with high surface areas up to 640 m2/g and uniform ultramicropore size of 0.6 nm, where porous properties are readily controlled by the substitutions of linkers and the crosslinker. Finally, as-synthesized mPTPMs exhibit good CO2 uptake capacities (0.106 g/g at 273 K and 1 bar) and high iodine uptake capacities up to 3.94 g/g within only 2.5 h, representing fast and efficient adsorbents for wider environmental applications.

Imidazole-Linked Crystalline Two-Dimensional Polymer with Ultrahigh Proton-Conductivity.

Proton-exchange membrane fuel cells are promising energy devices for a sustainable future due to green features, high power density, and mild operating conditions. A facile proton-conducting membrane plays a pivotal role to boost the efficiency of fuel cells, and hence focused research in this area is highly desirable. Major issues associated with the successful example of Nafion resulted in the search for alternate proton conducting materials. Even though proton carrier loaded crystalline porous organic frameworks have been used for proton-conduction, the weak host-guest interactions limited their practical use. Herein, we developed a crystalline 2D-polymer composed of benzimidazole units as the integral part, prepared by the condensation of aryl acid and diamine in polyphosphoric acid medium. The imidazole linked-2D-polymer exhibits ultrahigh proton conductivity (3.2 × 10-2 S cm-1) (at 95% relative humidity and 95 °C) in the pristine state, which is highest among the undoped porous organic frameworks so far reported. The present strategy of a crystalline proton-conducting 2D-polymer will lead to the development of new high performing crystalline solid proton conductor.

Efficient and Site-Specific 125I-Radioiodination of Bioactive Molecules Using Oxidative Condensation Reaction.

In this report, the novel and site-specific radioiodination of biomolecules by using aryl diamine and alkyl aldehyde condensation reaction in the presence of a Cu2+ catalyst under ambient conditions was reported. 125I-labeled alkyl aldehyde was synthesized using a tin precursor with a high radiochemical yield (72 ± 6%, n = 5) and radiochemical purity (>99%). The utility of the radioiodinated precursor was demonstrated through aryl diamine-installed c[RGDfK(C)] peptide and human serum albumin (HSA). Radioiodinated c[RGDfK(C)] peptide and HSA protein were synthesized with high radiochemical yields and purity. 125I-HSA protein showed excellent in vivo stability and negligible thyroid uptake as compared with directly radioiodinated HSA by using the tyrosine group. Excellent reaction kinetics and the in vitro and in vivo stabilities of 125I-labeled alkyl aldehyde have suggested the usefulness of the strategy for the radioiodination of bioactive molecules.

Catalyst-Free Synthesis of Aryl Diamines via a Three-Step Reaction Process.

The formation of C-N bonds with aryl amines is one of the most widely studied reactions in organic chemistry. Despite this, it is still highly challenging, often requiring expensive, precious metal-based catalysts. Here we report an easy catalyst-free methodology for constructing C-N bonds. The method, which proceeds via the in situ formation of closed ring amidinium ions, allows the preparation of a series of symmetrical and/or unsymmetrical aryl diamines in notably high yields (82-98%) and purity and with a variety of different substituents. The methodology is shown successful for the preparation of aryl diamines having para- and/or meta-substituted carboxyl, nitro, bromo, methoxy, or methyl groups. This green synthetic pathway, which is catalyst free, requires only three steps, and proceeds without the need for purification. Further, it is a new sustainable, economically viable method to achieve an otherwise challenging bond formation.

Highly Efficient and Reversible Iodine Capture in Hexaphenylbenzene-Based Conjugated Microporous Polymers

The effective and safe capture and storage of radioactive iodine (129I or 131I) is of significant importance during nuclear waste storage and nuclear energy generation. Here we present detailed evidence of highly efficient and reversible iodine capture in hexaphenylbenzene-based conjugated microporous polymers (HCMPs), synthesized via Buchwald–Hartwig (BH) cross-coupling of a hexakis(4-bromophenyl)benzene (HBB) core and aryl diamine linkers. The HCMPs present moderate surface areas up to 430 m2 g–1, with narrow pore size distribution and uniform ultramicropore sizes of less than 1 nm. Porous properties are controlled by the strut lengths and rigidities of linkers, while porosity and uptake properties can be tuned by changing the oxidation state of the HCMPs. The presence of a high number of amine functional groups combined with microporosity provides the HCMPs with extremely high iodine affinity with uptake capacities up to 336 wt %, which is to the best of our knowledge the highest reported to date. Two ...

Practical synthesis of 3,3-substituted dihydroquinoxalin-2-ones from aryl 1,2-diamines using the Bargellini reaction

The reaction of aromatic 1,2-diamines with trichloromethylcarbinols under mild, basic phase-transfer conditions provided expedient access to 3,3-disubsituted quinoxalin-2(1H)-ones in good to moderate yields. The use of unsymmetrical aryl diamines gave a regioisomeric mixture of products with the ratio shown to be dependent on the electronic nature of the aromatic substituents. 2,3-Diaminopyridines could also be used, showing excellent selectivity for the dihydro[3,2-b]pyridopyrazin-2-one isomer.

Product formation from phenolic compounds removal by laccases: A review

Lignolytic enzymes are very promising tools for biotechnological applications in water treatment. Among them, laccases (EC 1.10.3.2: p-diphenol:dioxygen oxidoreductase) are versatile enzymes with the ability to oxidize a wide range of aromatic and non-aromatic compounds (polyphenols, aryl diamines, anilines, methoxy substituted phenols, organic/inorganic metal compounds, etc.). Laccases have confirmed their potential for the degradation of recalcitrant residual phenolic compounds in water. Typically, oxidation of a laccase substrate leads to the formation of free radical with the concomitant loss of one electron and reduction of molecular oxygen into water. The formed radicals can react via non-enzymatic reactions i.e. oxidative condensation, and oxidative phenolic coupling or oxidative coupling, leading to the formation of soluble or non-soluble reaction products, several of them of polymeric nature. As many studies have highlighted the generation of products potentially more toxic than the parent molecules with the use of tertiary treatments such as advanced oxidative processes (AOPs) applied in water treatment plans, the identification of reaction products generated by the degradation of phenolic contaminants in water by laccases, and their potential toxicity, have to be investigated. This review summarizes and discuss progress made this last decades in identification of products and their risk assessment regarding their potential toxicity for a list of the most studied recalcitrant phenolic pollutants in water, such as dyes, bisphenol A, triclosan, nonylphenol, natural and synthetic hormones, etc.

Functionalization of indole at C-5 or C-7 via palladium-catalysed double carbonylation. A facile synthesis of indole ketocarboxamides and carboxamide dimers

Palladium-catalysed aminocarbonylation of 7-iodoindole derivatives (the parent compound and 5-bromo-7-iodoindole), as well as 5-iodoindole with various primary and secondary amines, including amino acid esters and chiral diamines, was carried out. In this way, a highly selective double carbonylation reaction at the C-7 was performed resulting in the formation of the corresponding indol-7-ylglyoxylamides when monoamines were used. The bromoarene moiety remained intact, so bromo-substituted glyoxylamides of practical importance have been synthesised in moderate to high yields. The use of chiral alkyl and aryl diamines as nucheophiles allowed the synthesis of a new family of dimeric 7-indole derivatives under moderate reaction conditions (10 bar, 100 °C). The aminocarbonylation at the C-5 position led to much lower chemoselectivities toward indol-5-ylglyoxylamides under similar conditions (40 bar CO, 50 °C).The aminocarbonylation of iodoindoles shows a strikingly different chemoselectivity depending on the basicity of the amine while primary and secondary amines of high basicity gave 2-ketocarboxamides in up to 98% chemoselectivity, aniline resulted in almost exclusive formation of the corresponding carboxamide product.

ChemInform Abstract: Synthesis of Aryl anti‐Vicinal Diamines via Aza‐Brook Rearrangement‐Initiated Nucleophilic Addition of α‐Silylamines to Imines.

An efficient protocol is described for the synthesis of vicinal diamines via aza-Brook rearrangement-initiated nucleophilic addition of α-silylamines to imines. Various symmetrical and unsymmetrical aryl diamine derivatives were prepared in moderate to high yields with high anti/syn diastereoselectivity.

Synthesis of aryl anti-vicinal diamines via aza-Brook rearrangement-initiated nucleophilic addition of α-silylamines to imines.

An efficient protocol is described for the synthesis of vicinal diamines via aza-Brook rearrangement-initiated nucleophilic addition of α-silylamines to imines. Various symmetrical and unsymmetrical aryl diamine derivatives were prepared in moderate to high yields with high anti/syn diastereoselectivity.

LacSubPred: predicting subtypes of Laccases, an important lignin metabolism-related enzyme class, using in silico approaches.

BackgroundLaccases (E.C. 1.10.3.2) are multi-copper oxidases that have gained importance in many industries such as biofuels, pulp production, textile dye bleaching, bioremediation, and food production. Their usefulness stems from the ability to act on a diverse range of phenolic compounds such as o-/p-quinols, aminophenols, polyphenols, polyamines, aryl diamines, and aromatic thiols. Despite acting on a wide range of compounds as a family, individual Laccases often exhibit distinctive and varied substrate ranges. This is likely due to Laccases involvement in many metabolic roles across diverse taxa. Classification systems for multi-copper oxidases have been developed using multiple sequence alignments, however, these systems seem to largely follow species taxonomy rather than substrate ranges, enzyme properties, or specific function. It has been suggested that the roles and substrates of various Laccases are related to their optimal pH. This is consistent with the observation that fungal Laccases usually prefer acidic conditions, whereas plant and bacterial Laccases prefer basic conditions. Based on these observations, we hypothesize that a descriptor-based unsupervised learning system could generate homology independent classification system for better describing the functional properties of Laccases.ResultsIn this study, we first utilized unsupervised learning approach to develop a novel homology independent Laccase classification system. From the descriptors considered, physicochemical properties showed the best performance. Physicochemical properties divided the Laccases into twelve subtypes. Analysis of the clusters using a t-test revealed that the majority of the physicochemical descriptors had statistically significant differences between the classes. Feature selection identified the most important features as negatively charges residues, the peptide isoelectric point, and acidic or amidic residues. Secondly, to allow for classification of new Laccases, a supervised learning system was developed from the clusters. The models showed high performance with an overall accuracy of 99.03%, error of 0.49%, MCC of 0.9367, precision of 94.20%, sensitivity of 94.20%, and specificity of 99.47% in a 5-fold cross-validation test. In an independent test, our models still provide a high accuracy of 97.98%, error rate of 1.02%, MCC of 0.8678, precision of 87.88%, sensitivity of 87.88% and specificity of 98.90%.ConclusionThis study provides a useful classification system for better understanding of Laccases from their physicochemical properties perspective. We also developed a publically available web tool for the characterization of Laccase protein sequences (http://lacsubpred.bioinfo.ucr.edu/). Finally, the programs used in the study are made available for researchers interested in applying the system to other enzyme classes (https://github.com/tweirick/SubClPred).

Synthesis, Structure, and Fungicidal Activity of Organotin Dithiocarbamates Derived from Pyridinamines and Aryl Diamines

A reaction of N-benzylpyridinamines with n-BuLi, followed by a reaction with CS2 and R3SnCl or R2SnCl2 (R = n-Bu, PhCH2, or Ph) gave a series of mononuclear organotin dithiocarbamates. A similar reaction of N,N'-bis(benzyl)-1,3-benzenediamine and N,N'-bis(benzyl)-2,6-pyridinediamine afforded dinuclear and macrocyclic organotin dithiocarbamates. All of these complexes were characterized by elemental analysis, IR, and multinuclear NMR (1H, 13C, and 119Sn). Their structures have been confirmed by the X-ray single crystal diffraction analysis, suggesting the dithiocarbamate groups acted as anisobidentate chelating ligands in these complexes. The primary fungicidal activity of these complexes was tested in vitro, showing that most complexes displayed good antifungal activity to Sclerotinia sclerotiorum.

A highly efficient oxidative condensation reaction for selective protein conjugation.

We hereby report a mild and efficient coupling reaction between alkyl aldehydes and aryl diamines. In the presence of a Cu(2+) or a Zn(2+) ion, oxygen (O2) in air is able to promote the oxidative condensation of the two readily preparable functional groups, forming stable benzimidazole linkages in neutral aqueous solution at room temperature (RT). We demonstrated that the reaction could be utilized to label a T4 lysozyme protein containing a chemically installed aryl diamine group with a fluorescent aldehyde dye molecule at 37 °C.

Scope of chemical fixation of carbon dioxide catalyzed by a bifunctional monomeric tungstate

The tungsten-oxo moiety in a simple monomeric tungstate, TBA2[WO4] (I, TBA=tetra-n-butylammonium), showed bifunctional activation of both CO2 and 1,2-phenylenediamine (1a). It was confirmed by 1H, 13C, and 183W NMR spectroscopies that adducts I–1a and I–(CO2)n (n=1 and 2) were formed by the reactions of I with 1a and CO2, respectively. These adducts played important roles in formation of the corresponding carbamic acid intermediates. The present bifunctionality could be applied to chemical fixation of CO2 even at atmospheric pressure with various kinds of structurally diverse aryl diamines, primary monoamines, propargylic alcohols, and propargylic amines into cyclic urea derivatives, 1,3-disubstituted urea derivatives, cyclic carbonates, and cyclic carbamates, respectively.