Piperazine Molecules Research Articles

Enhancing the water permeability of composite NF membranes through the incorporation of organic ions in the aqueous phase.

Composite nanofiltration (NF) membranes prepared using interfacial polymerization (IP) have gained significant attention in the field of wastewater treatment. In this study, sodium camphor sulfonate (CSA-Na) and tetraethylammonium chloride (TEAC) were employed as aqueous phase additives to regulate the diffusion of piperazine (PIP) molecules through electrostatic interactions. The dissociated CSA-Na and TEAC in the aqueous solution formed an organic structure at a certain concentration, restricting the interfacial transport behavior of PIP monomers. The results show that when the content of CSA-Na is 2% w/v, TEAC is 3.9% w/v, that is, the material dosage ratio is 1 : 3, and the NF membrane shows the best performance, with a water flux of 55.61 L m-2 h-1 (test pressure is 0.5 MPa), and MgSO4 rejection rate of more than 98%.

Thermodynamics and spectroscopic properties of N-methylpiperazine with propan-1-ol, 2-propen-1-ol, 2-propyn-1-ol

ABSTRACT The density (ρ), viscosity (η), and speed of sound (u) are reported for binary mixtures of N-methylpiperazine with aliphatic primary alcohols (propan-1-ol, 2-propen-1-ol, 2-propyn-1-ol) over the entire composition range from 303.15 K to 313.15 K and at atmospheric pressure 0.1 MPa. The excess parameters (VE,κs E), deviation in viscosity, and excess partial properties (, and ) of the components at infinite dilution were calculated from the density, speed of sound, and viscosity at experimental temperatures. All the investigated systems exhibit positive values of ∆η and ∆G *E and negative values of VE and κs E over the whole composition range. The obvious deviations attribute to the association between the primary alcohols and N-methyl piperazine molecules through the hydrogen bond of O-H· · ·N. A good agreement is obtained between excess quantities and FTIR spectroscopic data.

Poly[[(μ-aqua)[μ4-4-(carboxyl-atometh-yl)ben-zo-ato]cobalt(II)] hemi[1,4-bis-(pyridin-4-ylmeth-yl)piper-azine] hemihydrate

In the title com-pound, {[Co(C9H6O4)(H2O)]·0.5C16H20N4·0.5H2O}n, two-di-men-sional coordination polymer slabs are held together in the three-dimensional crystal structure by means of O-H⋯N hydrogen bonding between bound water mol-ecules and pyridyl N atoms of cocrystallized 1,4-bis-(pyridin-4-yl-meth-yl)piperazine mol-ecules.

Employing Visible Light To Construct Photoinitiated Polymerized Nanofiltration Membranes for High Permeation and Environmental Micropollutant Removal.

Improving the nanofiltration (NF) performance of membrane-based treatment is conducive to promoting environmental water recycling and addressing water resource depletion. Combinations of light, electricity, and heat with traditional techniques of preparing membranes should optimize membrane performance. Interfacial polymerization and photopolymerization were integrated to construct a photopolymerized thin-film composite NF membrane with a ridged surface morphology. Under visible light initiation, 2-acrylamido-2-methyl-1-propanesulfonic acid was crosslinked with the polyamide network. The control effects of light on the membrane surface and physicochemical properties were revealed via infrared thermal images and response surface methodology. To present the diffusion motion of piperazine molecules, molecular dynamics simulations were implemented. Through density functional theory simulations, the crosslinking mechanism of the photoinduced NF network was identified and verified. The surface physicochemical characteristics and perm-selectivity performance were systematically illustrated. The photopolymerized membrane outperformed the pristine in permeability and selective separation competence; without degradation of solute repulsion, the water permeation was enhanced to 33.5 L m-2 h-1 bar-1, 6.6 times that of the initial membrane. In addition, the removal of organic contaminants and antifouling capacities were improved. This work represents a novel lead for applying sustainable resources in constructing high-performance membranes for environmental challenges.

Simple and Efficient Synthesis of 3-Aryl-2-oxazolidinone Scaffolds Enabling Increased Potency toward Biofilms.

Infectious diseases caused by bacterial pathogens are a leading cause of mortality worldwide. In particular, recalcitrant bacterial communities known as biofilms are implicated in persistent and difficult to treat infections. With a diminishing antibiotic pipeline, new treatments are urgently required to combat biofilm infections. An emerging strategy to develop new treatments is the hybridization of antibiotics. The benefit of this approach is the extension of the useful lifetime of existing antibiotics. The oxazolidinones, which include the last resort antibiotic linezolid, are an attractive target for improving antibiofilm efficacy as they present one of the most recently discovered classes of antibiotics. A key step in the synthesis of new 3-aryl-2-oxazolidinone derivatives is the challenging formation of the oxazolidinone ring. Herein we report a direct synthetic route to the piperazinyl functionalized 3-aryl-2-oxazolidinone 17. We also demonstrate an application of these piperazine molecules by functionalizing them with a nitroxide moiety as a strategy to extend the useful lifetime of oxazolidinones and improve their potency against Methicillin-resistant Staphylococcus aureus (MRSA) biofilms. The antimicrobial susceptibility of the linezolid-nitroxide conjugate 11 and its corresponding methoxyamine derivative 12 (a control for biofilm dispersal) was assessed against planktonic cells and biofilms of MRSA. In comparison to linezolid and our lead compound 10 (a piperazinyl oxazolidinone derivative), the linezolid-nitroxide conjugate 11 displayed a minimum inhibitory concentration that was 4-16-fold higher. The opposite effect was seen in biofilms where the linezolid-nitroxide hybrid 11 was >2-fold more effective (160 μg/mL versus >320 μg/mL) in eradicating MRSA biofilms. The methoxyamine derivative 12 performed on par with linezolid. The drug-likeness of the compounds was also assessed, and all compounds were predicted to have good oral bioavailability. Our piperazinyl oxazolidinone derivative 10 was confirmed to be lead-like and would be a good lead candidate for future functionalized oxazolidinones. The modification of antibiotics with a dispersal agent appears to be a promising approach for eradicating MRSA biofilms and overcoming the antibiotic resistance associated with the biofilm mode of growth.

GO Treated with Aminoethyl‐Piperazine as a Reusable and Eco‐friendly Organocatalyst for Synthesis of Some Xanthen and Pyran Derivatives

AbstractGraphene Oxide (GO) containing 1‐(2‐aminoethyl) piperazine as a reusable, highly efficient and heterogeneous organocatalyst was prepared using a simple and green way. Epoxide groups on the surface of GO layers were replaced with 1‐(2‐aminoethyl) piperazine by an easy and green technique in a mild condition. The prepared catalyst (GO‐A.P.) was characterized using diverse microscopic and spectroscopic techniques. The presence of organic functional groups on the surface of GO‐A.P. was confirmed by Fourier transform infrared and Raman spectroscopy. X‐ray diffraction analysis showed an increase in the catalyst's interlayer spaces which confirm the successful presence of 1‐(2‐aminoethyl) piperazine molecules on the GO surface. Also interaction between the organic molecules and GO was established by thermogravimetric analysis via weight loss steps. Then, the capability of this catalyst was evaluated in a three‐component coupling reaction for one‐pot synthesis of 12‐aryl‐8,9,10,12‐tetrahydrobenzo[a]xanthen‐11‐one (A1–A7) and also 2‐amino‐4H‐pyrans (B1–B8) derivatives. The target products were obtained in high isolated yields. Furthermore, our catalyst was reusable at least for 5 runs with no significant decrease in its activity.

Retarding the diffusion rate of piperazine through the interface of aqueous/organic phase: Bis-tris propane tuned the trans-state of ultra-low concentration piperazine

An urgent challenge during the preparation of polyamide thin film composite membrane via the interfacial polymerization method was excessive diffusion rate of piperazine to form uncontrollable polyamide layer thickness, ultimately leaded to low water permeability to increase the operating cost. Herein, a uniquely new method, which brought down one order of magnitude of piperazine concentration to ultra-low grade (0.01% w·v−1) to retard the diffusion rate, was utilized to avoid the problem. However, the ultra-low concentration of piperazine could not easily react with trimesoyl chloride, bis-tris propane as conditioning agent was needed to overcame the trouble. The kinetics diffusion process of piperazine under the function of bis-tris propane was intensively studied by molecular dynamics simulation and other characterizations. Bis-tris propane could combine with piperazine to generate intermolecular force and then carry piperazine molecules moving toward the interface of aqueous/organic phase, which tuned the trans-state of piperazine to the benefit of rection. This work offered a novelty insight to surmount the problem of the excessive diffusion rate, which could promote the development of membrane technology.

Conformational Analysis and DFT Investigations of 1-(4-Fluorophenyl)Piperazine by ELF and LOL, Inhibitory activity against Alzheimer’s Disease, and ADME Prediction

This study reports 1-(4-Fluorophenyl)Piperazine molecule structural and electronic properties calculated at the DFT/B3LYP level. A potential energy surface scan along the rotational bonds discovered the most stable minimum energy conformer of the title compound. Frontier molecular orbital (FMO) analyses, density of state (DOS), molecular electrostatic potential (MEP), and global and chemical reactivity descriptors were also used to investigate the reactivity of the pFPP molecule. In addition, ELF and LOL analysis were performed. In silico biological studies such as drug-likeness, ADME, and toxicity properties were also performed. Molecular docking studies are performed to predict the anti-Alzheimer agent enzyme (AChE) active site of the pFPP. The docking predicts the possibility of a potential drug to improve Alzheimer's disease (AD) treatment.

Piperazine selenium nanoparticle (Pipe@SeNP's): A futuristic anticancer contender against MDA-MB-231 cancer cell line

Drug resistance is a major drawback of breast cancer management mainly in treatment failure. The main objective of the current study is to investigate whether Piperazine selenium nanoparticles (Pipe@SeNP's) can induce apoptosis in breast cancer cell lines. Piperazine molecule (pipe) was synthesized and characterized using different spectral studies such as 1H-NMR, 13C-NMR, LCMS, and FTIR. Pipe@SeNP's was synthesized and amply characterized with UV-Vis spectra, FT-IR, SEM, EDX, XRD, and DLS highest size distribution was found to be 26.39 nm compared to other sizes with 3.8 mV zeta potential value. Before the synthesis of the Pipe@SeNP's, the core chemical was assessed for their Pharmacophore model, PASS, ADME, and BBB. All the computational assays strongly indicated the potency of the molecule. Pipe@SeNP's was treated with both normal (PBMC) and cancerous (MDA-MB-23) cell lines and investigated their dose optimization, and cytotoxicity by MTT and SRB assays. The colony morphological changes and cell proliferation inhibitory effect of Pipe@SeNP's were monitored up to 8 hrs against cancer and normal cell lines compared to etoposide drug with colony formation and scratch wound assay. The efficacy of normal and cancerous cell death patterns was examined in a flow cytometer. The data showed that 61.92% of cells were dead in the late apoptotic phase and 22.60% of cells in the early apoptotic stage compared to standard drug etoposide 13.41% of cells were in the early apoptotic stage, 47.48% of cells in the late apoptotic phase and 20.65% of cells undergo necrosis. This revealed data strongly indicated that, Pipe@SeNP's could be of great potential in futuristic drug development against breast cancer cells.

Modulating interfacial polymerization with phytate as aqueous-phase additive for highly-permselective nanofiltration membranes

Modulating interfacial polymerization (IP) process has been recognized as an effective way to optimize the physicochemical structure of polyamide membranes and thus elevating nanofiltration performance. Herein, phytic acid dodecasodium salt (PADS), a small molecule salt with high solubility, is used as an aqueous-phase additive to modulate the piperazine (PIP) monomers diffusion behavior via electrostatic interaction during the IP process. The PADS with a high charge density can form long-range electrostatic interaction with the PIP molecules to retard their diffusion. The diffusion coefficient of PIP can be effectively modulated within an order of magnitude (∼10−5-10−6 cm2 s−1) by varying the amount of PADS. Accordingly, the growth of polyamide layer is inhibited and the membrane thickness is reduced from 95 nm to 50 nm. The optimized membrane presents a two-fold increase in water permeance while maintaining excellent salt rejection performance (Na2SO4 rejection >97%), outperforming the benchmark commercial nanofiltration membranes.

Poly(vinylidene fluoride) Substrate-Supported Polyamide Membrane for High-Temperature Water Nanofiltration

Conventional polysulfone and polyethersulfone membrane-supported polyamide (PA) nanofiltration (NF) membranes suffer an obvious performance decline due to the drastic pore shrinkage of their membranes during high-temperature (HT) desalination processes. Herein, a thermally stable PA NF membrane (PVDF-IP-2) was successfully constructed over a relatively hydrophobic polyvinylidene fluoride (PVDF) membrane using a continuous interfacial polymerization (CIP) method. The PVDF-IP-2 membrane had a moderate water permeance of 8.3 L m–2 h–1 bar–1 and a 99.7% Na2SO4 rejection at room temperature, which were comparable to those of commercial NF membranes. Introducing calcium ions (Ca2+) into the aqueous solutions further confined the transport rate of the piperazine monomer across the reaction interface through the coordination functions between Ca2+ and piperazine molecules, forming a high-flux (15.9 L m–2 h–1 bar–1 at room temperature) NF membrane (PVDF-IP-Ca) with an excellent Na2SO4 rejection (∼98.6%). Impressively, the PVDF-IP-Ca membrane presented an excellent antifouling behavior and performance stability during both fouling and high-temperature filtration tests. The Ca2+-assisted IP (Ca–CIP) strategy is expected to be a facile and universal approach to preparing TFC desalination membranes for HT environmental applications on relatively hydrophobic supports.

Crystal structure and Hirshfeld surface analysis of the hydrated 2:1 adduct of piperazine-1,4-diium 3,5-di-nitro-2-oxidobenzoate and piperazine.

The crystal structure of the adduct piperazine-1,4-diium 3,5-di-nitro-2-oxidobenzoate-piperazine-water (2/1/2) shows the existence of a 3,5-di-nitro-salicylate dianion (DNSA2-) and a protonated piperazine-1,4-diium cation (PIP2+) along with a piperazine mol-ecule. The formula of the title adduct in the asymmetric unit is 2C4H12N2 2+·2C7H2N2O7 2-·C4H10N2·2H2O with Z = 1. The piperazine ring in the piperazine-1,4-diium cation and in the neutral piperazine mol-ecule adopt chair conformations. All O atoms in the DNSA2- moiety and the water mol-ecule act as hydrogen-bonding acceptors for various inter-molecular O-H⋯O, N-H⋯O and C-H⋯O inter-actions, which stabilize the crystal structure. Various supra-molecular architectures formed by the different inter-molecular inter-actions are discussed. The relative contribution of various inter-molecular contacts is analysed with the aid of two-dimensional (full and decomposed) fingerprint plots, indicating that H⋯O/O⋯H (50.2%) and H⋯H (36.2%) contacts are the major contributors to the stabilization of the crystal structure.

Multirole Regulations of Interfacial Polymerization Using Poly(acrylic acid) for Nanofiltration Membrane Development.

Effective control of monomer diffusion and reaction rate is the key to achieving a controlled interfacial polymerization (IP) and a high-performance nanofiltration (NF) membrane. Herein, an integration of multirole regulations was synchronously realized using poly(acrylic acid) (PAA) as an active additive in a piperazine (PIP) aqueous phase. Thanks to synergistic interactions, including hydrogen bonding, electrostatic interaction, and covalent bonding between PAA and PIP molecules, together with the increased viscosity of the solution, PIP diffusion was rationally controlled. Moreover, interfacial polycondensation was also restrained via the modestly reduced pH of the aqueous solution. These contribute to the formation of a thinner, looser, more hydrophilic, and higher negatively charged PAA-decorated polyamide selective layer with a unique nanostrand-nodule morphology. The harvested NF-PAA/PIP membrane showed an ∼70% rise in water permeability (up to 23.5 L·m-2·h-1·bar-1) while retaining high Na2SO4 and dye rejections. Furthermore, the optimized NF-PAA/PIP membrane presented a superior fouling resistance capability for typical pollutants, as well as long-term stability during successive filtration. Thus, this work offers a straightforward and impactful approach to regulating IP and promoting NF membrane properties.

1,3,5-Tri-fluoro-2,4,6-tri-iodo-benzene-piperazine (2/1).

The single-crystal structure of the title compound, C4H10N2·2C6F3I3, features a moderately strong halogen bond between one of the three crystallographically distinct iodine atoms and the nitro-gen atom. The iodine-nitro-gen distance is 2.820 (3) Å, corresponding to 80% of the sum of their van der Waals radii. The C-I⋯N halogen bond angle is 178.0 (1)°, consistent with the linear inter-action of nitro-gen via a σ-hole opposite the carbon-iodine covalent bond. The other two iodine atoms do not engage in halogen bonding. Some weak C-H⋯F and -H⋯I interactions are also observed. The complete piperazine molecule is generated by symmetry.

A novel chlorocadmate hybrid cocrystal delivering intermolecular charge transfer enhanced nonlinear optical properties and optical limiting

Employing the donor-acceptor configuration of cocrystals, the intermolecular charge transfer enhanced third order nonlinear optical properties and the optical limiting behaviour of a novel chlorocadmate cocrystal Cd 2 Cl 6 OH 2 2 C 4 H 12 N 2 n ( 1 ) are reported. Optimization of crystal growth parameters is discussed to achieve bulk single crystal with reduced crystal defects by slow solvent evaporation technique. The acid hydrolysis of the piperazine molecule during the pH optimization converted it into piperazine-1,4-diium, which is neutralized by Cd 2 Cl 6 OH 2 2 2 - via hydrogen bond interactions. The intermolecular charge transfer responsible for optical nonlinearity in 1 is proved possible by calculating the intermolecular interaction energies at HF/3-21G level of quantum mechanical calculations. The two-photon absorption coefficient measured at different nanosecond pulsed laser intensities is found to vary, which explicitly confirmed sequential 2 PA in 1 . Lower optical limiting threshold of 1 measured under CW and nanosecond pulsed green laser regime ( ( 1.027 ± 0.02 ) × 10 3 Wcm -2 and ( 1.87 ± 0.02 ) × 10 12 Wm -2 respectively) with coherent dielectric, thermal, mechanical, linear absorption and emission properties showed its suitability for an efficient optical limiting device application. • A Novel intermolecular charge transfer cocrystal for NLO applications is reported. • Sequential two-photon absorption was conclusively proved from intensity-dependent β. • Intermolecular charge transfer interactions assisted optical nonlinearity is proved possible in the title material. • Third order nonlinear optical susceptibility (χ (3) ) of title cocrystal is found to be (0.527 ± 0.008) × 10 −6 esu. • Optical limiting threshold of title cocrystal for nano pulsed (100 mJ, 532 nm) and CW (100 mW, 532 nm) laser irradiance are calculated.

Nanofiltration membrane combining environmental-friendly polycarboxylic interlayer prepared from catechol for enhanced desalination performance

The strategy of introducing a hydrophilic interlayer on the porous substrate has been widely applied in the modification of nanofiltration (NF) membranes. Herein, an environmentally friendly polycarboxylic interlayer is prepared from the mixture of catechol and sodium periodate (SP). Catechol is easy to oxidize to generate reactive o-quinones which undergoes phenolic polymerization to form covalent polymer with the carboxyl group, with the effect of SP initiation. Due to the introduction of carboxylic group, the interlayer is hydrophilic and can store more piperazine molecules to provide a more uniform platform for interfacial polymerization, which is conductive to form a thin and dense polyamide (PA) active layer. Compared with the traditional membrane, the modified thin film composite (TFC) membrane exhibits 1.7-fold of permeance (up to 15.4 ± 1 L·m−2·h−1 bar−1), maintaining a high rejection of Na2SO4 (98.42 ± 1.2%). Although the TFC membrane without an interlayer tends to be thick and defective in low PIP concentration, the role of the interlayer can eliminate this limitation. Besides, the modified TFC membrane possesses a high electronegativity with the fact that isoelectric point (3.29) has been lower than that of the traditional membrane, which has the potential to separate negative organic pollutants in the wastewater treatment.

DFT Study of Conformational Analysis, Molecular Structure and Properties of para-, meta- and ortho 4-Methoxyphenyl Piperazine Isomers

In this study, conformer analysis of isomer structures of para-, meta- and ortho 4-methoxyphenyl piperazine molecules was performed using the Spartan 08 package program. The optimized geometrical parameters, energies for the highest occupied molecular orbital and the lowest unoccupied molecular orbitals, chemical reactivity descriptors, nonlinear optical properties, Mulliken population analysis, molecular electrostatic potential map, thermodynamic properties and UV–Vis spectral analysis of isomers of the N-(4-methoxyphenyl) piperazine molecule were predicted using the density functional theory (DFT) and TD-DFT/B3LYP/6-311++G(d,p) methods. The theoretical results obtained were compared with experimental results available in the literature so far, and these results were discussed for each isomer.

Design, synthesis, anti-tobacco mosaic viral and molecule docking simulations of urea/thiourea derivatives of 2-(piperazine-1-yl)-pyrimidine and 1-(4-Fluoro/4-Chloro phenyl)-piperazine and 1-(4-Chloro phenyl)-piperazine – A study

The objectives of the present work are to design, syhthesize and introduce novel urea/thiourea derivatives of 2-(piperazine-1-yl)-pyrimidine and 1-(4-Fluoro/4-Chloro phenyl)-piperazine molecules as tobacco mosaic virus (TMV) inhibitors. A series of urea/thiourea derivatives containing pyrimidine and piperazine moieties were synthesized, characterized using Fourier-transform infrared (FTIR) mass spectra, nuclear magnetic resonance (NMR) spectroscopy, elemental analysis and evaluated their sustainability using biological experiments. The anti-viral bioassay of the title compounds showed an antiviral activity against TMV. The compounds synthesized, 9j, 6g and 3d, showed highly-potential curative, protective, and inhibitory activities against TMV at 500 mg/mL formulation. All these compounds were allowed to quantum-polarized-ligand (quantum mechanical and molecular mechanical (QM/MM)) docking experiments. The compounds 9j, 6g and 3d structurally exhibited identical higher affinity towards TMV-Helicase and TMV-Coat proteins. The docking interactions proposed had two stage inhibition of TMV virus by binding to coat protein and helicase for inhibition of RNA replication. The long-range molecular dynamics (150 ns) simulations has revealed more consistency by 9j, 6g and 3d. The present study outcomes good binding propensity for active-tunnel of TMV-Hel enzyme, by these thiourea, urea derivatives, 9j, 6g and 3d, to suggest that the designed and synthesized were ideal for proposing as selective novel inhibitors to target for TMV.

Organic Amines as Targeting Stabilizer at the Polymer/Fullerene Interface for Polymer:PC 61 BM Solar Cells

Herein, it is demonstrated that a small amount (0.05% in weight ratio) of polyethyleneimine (PEI) can effectively suppress the “burn‐in” degradation of both PTB7‐Th:PC61BM and P3HT:PC61BM cells, similar to the piperazine derivatives, suggesting that organic amines can serve as universal stabilizer in polymer:PC61BM solar cells. Light‐induced electron spin resonance (LESR) spectroscopy measurement shows a higher ESR signal intensity of PC61BM anions in 0.2% PEI‐doped film than in 1% piperazine‐doped film. Moreover, no piperazine is detected in a 10% (w/w) piperazine‐doped film by gas chromatography–mass spectrometry (GSMS). These results suggest that the residual piperazine in the blend film is very low, which can be understood by the high volatility of piperazine. Quantum calculations are performed on the intermolecular binding energy (EB) between polymer (using model repeating units), PC61BM, and piperazine molecules. Results reveal that piperazine prefers to localize at the polymer:fullerene interface by complexing with PC61BM (in P3HT:PC61BM) or PTB7‐Th (in PTB7‐Th:PC61BM system), which indicates that the photo dimerization of PC61BM which causes the “burn‐in” degradation of polymer:fullerene solar cells mainly happens at the donor/acceptor interface, and the organic amine serves as the targeting stabilizer at the interface.

SYNTHESIS, CRYSTAL STRUCTURE AND THERMAL STUDIES OF TRIPHENYLSILANOL-PIPERAZINE ADDUCT

The solid-state structure of triphenylsilanol-piperazine adduct was reported from optimized reaction conditions. The molecular composition was further supported by elemental analysis, FT-IR, multinuclear NMR (1H and13C) and TGA. In solid-state, the four triphenylsilanols are associated in tetrameric form with one piperazine molecule through intra and intermolecular hydrogen bonds that lead to the new type of hydrogen bonding. The molecule represents one of the rare examples of triphenylsilanol-amine derivatives with a new hydrogen-bonding pattern.