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Piperazine is an important functional unit of many clinically approved drugs, including chemotherapeutic agents. In the current study, methyl piperazine was incorporated and eight salicylaldehyde-derived piperazine-functionalized hydrazone ONN-donor ligands (L) and their Pt(II) complexes (L-PtCl) were prepared. The structures of all these ligands (L1–L8) and Pt(II) complexes (C1–C8) were determined using 1H and 13C NMR, UV-vis, FT-IR and HR-ESI MS analyses, whereas the structures of C1, C5, C6, C7 and C8 were determined in the solid state using single crystal X-ray diffraction analysis. Solution state stabilities of C3, C4, C5 and C6 were determined via time-dependent UV-vis spectroscopy. All these complexes (C1–C8) were studied for their anticancer effect in pancreatic ductal adenocarcinoma cells, including BxPC3, MIAPaCa-2 and PANC1 cells. C1–C8 displayed a potential cytotoxic effect in all these cancer cells, among which C5, C6 and C8 showed the strongest inhibitory effect in comparison with standard chemotherapeutic agents, including 5-fluorouracil (5-FU), cisplatin (CP), oxaliplatin and doxorubicin (DOX). C5, C6 and C8 suppressed the growth of pancreatic cancer cells in a dose-dependent manner. Moreover, C5, C6 and C8 inhibited clonogenic potential and invasion ability and induced apoptosis in PANC1 cells. Importantly, C5, C6 and C8 synergized the anticancer effect with PARP inhibitors, including olaparib, veliparib and niraparib, in pancreatic cancer cells, thus suggesting an important role of C5, C6 and C8 in induction of apoptosis in combination with PARP inhibitors. C5 combined with PARP inhibitors induced caspase3/7 activity and suppressed ATP production. Mechanistically, C5, C6 and C8 inhibited EZH2 protein expression to suppress EZH2-dependent tumorigenesis. Overall, these results highlighted the importance of these piperazine-functionalized Pt(II) complexes as potential anticancer agents to suppress pancreatic ductal adenocarcinoma tumorigenesis by targeting the EZH2-dependent pathway. [ABSTRACT FROM AUTHOR]

Trimetazidine (TMZ) is a promising emerging therapeutic piperazine derivative for renal pathologies. However, the nephroprotective mechanism of TMZ against heavy metal-induced toxicity is unknown. This study, therefore, aimed to explore whether TMZ could mitigate mercury-induced nephrotoxicity in rats. Rats were injected TMZ (3 mg/kg bw) and/or mercury chloride (HgCl2) (4 mg/kg bw) for 4 days (n = 6 rats per group). The blood analysis revealed marked increases in creatinine, urea and uric acid levels in HgCl2 group compared to the control. HgCl2 induced prominent decreases in renal superoxide dismutase (SOD), catalase (CAT), glutathione peroxide (GPx) activities compared to the control followed by marked increases in the levels of malondialdehyde (MDA), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), caspase-3 and caspase-9. Whereas the renal levels of anti-inflammatory cytokines interleukin-4 (IL-4) and interleukin-10 (IL-10) reduced considerably compared to the control. Contrarily, it was found that in the rats administered TMZ + HgCl2, levels of renal markers, MDA, TNF-α, IL-6 and caspases-3/-9 were prominently reduced compared to the HgCl2 group. The renal SOD, CAT, GPx, IL-4, and IL-10 were markedly elevated along with ameliorated histopathological lesions. On the whole, therefore, TMZ could be repurposed for blocking HgCl2 nephrotoxicity via inhibition of oxidative inflammation and apoptosis in rats. [ABSTRACT FROM AUTHOR]

The current study was aimed to synthesize piperazine‐based bis‐Schiff base derivatives (1–15) and were also screened in vitro for their inhibition against urease enzyme under the positive control of thiourea drug (IC50 value of 36.40±2.35 μM). Among the tested analogs, the maximum potency was shown by analog 2 with the lowest IC50 value of 2.10±1.10 μM, whereas the minimum activity was demonstrated by the scaffold 5 having an IC50 value of 49.60±6.10 μM. The experimental results of urease activity prompted us to investigate and propose a possible mechanism of how actives analogs of piperazine derivatives will interacts with the catalytic sites of targeted urease enzymes. For this purpose, molecular docking with Auto Dock Vina gave us an insight into the binding interactions of the active compounds to different amino acid residues of the targeted urease enzyme. [ABSTRACT FROM AUTHOR]

Poly(ionic liquid)s combine the unique properties of ionic liquids (ILs) within ionic polymers holding significant promise for energy storage applications. It is reported here the synthesis and characterization of a new family of poly(ionic liquid)s synthesized from cationic piperazinium ionic liquid monomers. The cationic poly(acrylamide piperazinium) in combination with sulfonamide anions like bis(trifluoromethanesulfonyl) imide (TFSI) and bis(fluorosulfonyl) imide (FSI) are characterized as solid polymer electrolytes. The polymer electrolytes in combination with pyrrolidonium ILs and LiFSI show high ionic conductivity, 5×10−3 S cm−1 at 100 °C. Piperazinium polymer electrolytes show excellent compatibility with lithium metal reversible plating and stripping at high current density and low temperature 40 °C. [ABSTRACT FROM AUTHOR]

A base-induced synthesis of 2-(4-(2-(phenylthio)ethyl)piperazinyl) acetonitriles by reaction of disulfides, 1-(chloromethyl)-4-aza-1-azonia bicyclo[2.2.2]octane chloride and trimethylsilyl cyanide is reported. The scope of the method is demonstrated with 30 examples. The reaction mechanism research indicates that the three-component reaction would be a SN2 reaction. The products exhibit good activities towards advanced synthesis of aqueous soluble acyl-CoA: cholesterol O-acyltransferase-1 (ACAT-1) inhibitors. Our work is superior as it uses less-odor disulfides as carbon sources and EtOH as solvent in a water and dioxygen insensitive reaction system, followed by a simple purification process. [ABSTRACT FROM AUTHOR]

Introduction: Nuclear factor kappa (NF-κB) plays a key role in cancer cell proliferation; thus, small molecule inhibitors of NF-κB activity can effectively inhibit breast cancer (BC) progression. We have previously reported oxazine and piperazine-linked pyrimidines as novel anti-cancer agents that can suppress NF-κB activation in BC cells. Moreover, the TRX-01 compound, an oxazine-linked pyrimidine, inhibited MCF-7 cells at a concentration of 9.17 µM in the Alamar Blue assay. Methods: This work involved the analysis of frontier molecular orbitals, HOMO-LUMO interactions, and molecular electrostatic potential for the TRX-01 structure. Additionally, the TRX-01 compound was studied for cytotoxicity, and migration as well as invasion assays were performed on BC cells. Results: Finally, TRX-01 blocked the translocation of NF-κB from the cytoplasm to the nucleus in MCF-7 cells and reduced NF-κB and IκBα levels in a dose-dependent manner. It also suppressed migratory and invasive properties of BC cells. Conclusion: Overall, the data indicates that TRX-01 can function as a novel blocker of BC growth and metastasis by targeting NF-κB activation. [ABSTRACT FROM AUTHOR]

Polylactic acid has good biodegradability and processability, but its flammability and serious droplet characteristics limit its development and application. Therefore, developing safer flame‐retardant PLA materials is crucial. This research develops a novel flame‐retardant polylactic acid (PLA) material blend, utilizing aluminum diethylphosphinate (AlPi), piperazine pyrophosphate (PAPP), and β‐cyclodextrin. Optimal synergy occurs at a 5:1 PAPP/β‐CD mass ratio with 4 wt.% AlPi. This combination significantly reduces the heat release peak from 294.89 to 144.21 kW·m−2 and generates non‐combustible residues. The sample forms a stable, uniform carbon layer during combustion due to hydrogen bond crosslinking and Lewis acid–base reactions. The activation energy (Eα) is raised from 264.99 to 281.08 kJ·mol−1 between 312 and 402°C. Thus, an AlPi‐PAPP‐β‐CD based P‐C‐N composite flame retardant is investigated, offering a promising research direction for developing fire‐safe polylactic acid materials. This research may yield valuable insights for diverse applications. [ABSTRACT FROM AUTHOR]

To overcome the poor solubility, permeability, and bioavailability of the plant isoflavone daidzein (DAI), a novel salt of DAI with anhydrous piperazine (PIP) was obtained based on cocrystallization strategy. The new salt DAI-PIP was characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy, and optical microscopy. The results showed that the maximum apparent solubility (Smax) of DAI-PIP increased by 7.27-fold and 1000-fold compared to DAI in pH 6.8 buffer and water, respectively. The peak apparent permeability coefficient (Papp) of DAI-PIP in the Caco-2 cell model was 30.57 ± 1.08 × 10-6 cm/s, which was 34.08% higher than that of DAI. Additionally, compared to DAI, the maximum plasma concentration (Cmax) value of DAI-PIP in beagle dogs was approximately 4.3 times higher, and the area under the concentration-time curve (AUC0-24) was approximately 2.4 times higher. This study provides a new strategy to enhance the dissolution performance and bioavailability of flavonoid drugs, laying a foundation for expanding their clinical applications. [ABSTRACT FROM AUTHOR]

Heterocyclic chemistry is one of the emerging branches of organic chemistry due to its growing attention in pharmacology. Piperazine is a dinitrogen-containing heterocycle that spans many applications, including anticancer, anticonvulsant, antidepressant, antimicrobial, antimalarial, antiviral, antitubercular, anti-inflammatory, activities etc. In a similar fashion, the second moiety, i.e., acetanilide, an N-phenylacetamide, also executed a large number of bioactivities, which included anticancer, antileishmanial, antipyretic, analgesic, antidiabetic, antiviral potential, etc. Both moieties have large-scale potential to show bioactivities in different aspects. When both moieties combine in a single molecule, it forms a potent biological compound. A number of precursors have been used for the synthesis of piperazine-based acetanilides. In this review, we have addressed different synthetic strategies that have been reported in the past. [ABSTRACT FROM AUTHOR]

Piperazines constitute an important structural feature of many pharmaceuticals. For the discovery of new drugs, the ability to modify the lead compound's structure is crucial. Herein, we provide an efficient method for the synthesis of chiral 2,3,5-trisubstituted piperazine structures. Our route enables the synthesis of several novel chiral aryl aziridinyl ketones that could be converted into aziridine-fused bicyclic imines. The reduction of these imines and the nucleophilic ring-opening reaction of the aziridine ring allowed us to synthesize highly functionalized piperazine derivatives. [ABSTRACT FROM AUTHOR]

A series of new analogs based on benzothiazole‐piperazine conjugates were synthesized and assessed to investigate their anticancer properties using in vitro and in silico techniques. The compounds 3 a–3 h were tested against prostate (C4‐2) cancer cells, and the results revealed that all the compounds showed significant inhibitory activity against C4‐2 cells (>50 % inhibition at 20 μM). Among all, 2‐(4‐(pyrimidin‐2‐yl) piperazin‐1‐yl) benzo[d]thiazole demonstrated the most prominent activity in the cell viability assay conducted displaying an IC50 value of 19.98 μM. In vitro studies have demonstrated that the compound can selectively target the androgen receptor (AR) and reduce the expression of several androgen‐responsive genes, including EAF2, ELL2, PSA and CALR genes, in castration‐resistant prostate cancer cells. Molecular docking results also revealed that all the compounds exhibited good energy binding scores against the androgen receptor target (PB ID: 2PNU) particularly compound 3 g which showed a maximum binding energy of −9.87 kcal/mol followed by other compounds as well as the established prostate cancer drug, enzalutamide, with a binding energy of −5.66 kcal/mol. Docking results were further supported by MD simulation studies, which confirmed that the ligand+protein complex was in stable conformation throughout the simulation time of 100 nanoseconds. Collectively, the present results, stemming from a combination of in vitro and in silico examinations, demonstrate that compound 3 g displays notable anti‐cancer characteristics, implying its viability as a prospective anti‐cancer pharmaceutical subject to clinical validation and subsequent development. [ABSTRACT FROM AUTHOR]

Breast cancer (BC) is the second leading cause of cancer‐related mortality in women, and targeting biological pathways such as the JNK pathway has proven to be a viable therapeutic target for BC therapy. Here, we synthesized piperazin‐2‐yl‐pyrimidines and evaluated them for anticancer activity against MCF‐7 cells. In addition, antioxidant, reactive oxygen species (ROS) inhibition, caspase activity, and toxicity in platelets were studied in the presence and absence of active compound IA‐6 or IA‐7. Our detailed experimental analysis found that the compound IA‐7 showed anticancer activity by either activating p‐JNK or by inducing radical species in cancer and thrombosis model. Evident to in vitro analysis, the structure based molecular interaction studies of binding of IA‐7 to JNK3S exhibited a significant binding energy of −7.56 kcal/mol which was found to be a better binder when compared to previously reported JNK inducer (PC‐12). Overall, we herein report the analytically pure IA‐7 as lead structure that could be used as a template to develop target based anticancer agents where JNK modulation is predominant. [ABSTRACT FROM AUTHOR]

Fibroblast activation protein (FAP) has emerged as a highly promising target for cancer diagnostic imaging and targeted radionuclide therapy. To exploit the therapeutic potential of suitably radiolabeled FAP inhibitors (FAPIs), this study presents the design and synthesis of a series of FAPI dimers to increase tumor uptake and retention. Preclinical evaluation and a pilot clinical PET imaging study were conducted to screen the lead compound with the potential for radionuclide therapy. Methods: Three new FAPI dimers were synthesized by linking two quinoline-based FAPIs with different spacers. The in vitro binding affinity and preclinical small animal PET imaging of the compounds were compared with their monomeric counterparts, FAPI-04 and FAPI-46. The lead compound, [68Ga]Ga -LNC1013, was then evaluated in a pilot clinical PET imaging study involving seven patients with gastrointestinal cancer. Results: The three newly synthesized FAPI homodimers had high binding affinity and specificity in vitro and in vivo. Small animal PET imaging and biodistribution studies showed that [68Ga]Ga-LNC1013 had persistent tumor retention for at least 4 h, also higher uptake than the other two dimers and the monomer counterparts, making it the lead compound to enter clinical investigation. In the pilot clinical PET imaging study, seven patients were enrolled. The effective dose of [68Ga]Ga-LNC1013 was 8.24E-03 mSv/MBq. The human biodistribution of [68Ga]Ga-LNC1013 demonstrated prominent tumor uptake and good tumor-to-background contrast. [68Ga]Ga-LNC1013 PET imaging showed potential in capturing primary and metastatic lesions and outperforming 18F-FDG PET in detecting pancreatic and esophageal cancers. The SUVmax for lesions with [68Ga]Ga-FAPI-46 decreased over time, whereas [68Ga]Ga-LNC1013 exhibited persistently high tumor uptake from 1 to 4 h post-injection. Conclusion: Dimerization is an effective strategy to produce FAPI derivatives with favorable tumor uptake, long tumor retention, and imaging contrast over its monomeric counterpart. We demonstrated that [68Ga]Ga-LNC1013, the lead compound without any piperazine moiety, had superior diagnostic potential over [68Ga]Ga-FAPI-46 and 18F-FDG, suggesting the future potential of LNC1013 for radioligand therapy of FAP-positive cancers. [ABSTRACT FROM AUTHOR]

Breast cancer and lung cancer causes a high rate of mortality all over the world. Pursuing our efforts toward searching for efficient anticancer agents herein a series of coumarin/piperazine hybrids 10a-f, 12a-d, 14 were synthesized and subsequently assessed for their potential In Vitro anticancer activity, against A549 (Lung cancer) and MCF-7 (breast cancer) cell lines using MTT assay. Encouragingly, all the synthesized compounds displayed varying degrees of effectiveness, ranging from good to moderate activity against these two cancer cell lines. However, amongst all the compounds synthesized, compound 12c exhibited notably higher potency against both A549 and MCF-7 cell lines, with an IC50 of 0.40 µM and 0.51 µM, respectively. Additionally, the study delved deeper by conducting EtBr/AO assays, unveiling the induction of apoptosis. Furthermore, investigations into Reactive Oxygen Species (ROS) were conducted by using DCFH-DA dye. To understand the behavioral patterns and selectivity of the synthesized compounds, computational techniques were employed alongside experimental analysis. Utilizing density functional theory (DFT) calculations, electronic and structural characteristics were determined for compound 12c These calculations were then compared and associated with the observed biological effects. Additionally, molecular docking was utilized to investigate how compounds 12c interacted with crucial apoptotic genes, specifically targeting p53 and caspase 3. Compound 12c exhibited docking scores of −8.4 kcal/mol and −7.9 kcal/mol for p53 and caspase 3 respectively. Lastly, an in Silico ADME study was performed to evaluate the compounds' potential as drug candidates. [ABSTRACT FROM AUTHOR]

A new series of piperazine derivatives were synthesized and studied with the aim of obtaining dual inhibitors of P-glycoprotein (P-gp) and carbonic anhydrase XII (hCA XII) to synergistically overcome the P-gp-mediated multidrug resistance (MDR) in cancer cells expressing the two proteins, P-gp and hCA XII. Indeed, these hybrid compounds contain both P-gp and hCA XII binding groups on the two nitrogen atoms of the heterocyclic ring. All compounds showed good inhibitory activity on each protein (P-gp and hCA XII) studied individually, and many of them showed a synergistic effect in the resistant HT29/DOX and A549/DOX cell lines which overexpress both the target proteins. In particular, compound 33 displayed the best activity by enhancing the cytotoxicity and intracellular accumulation of doxorubicin in HT29/DOX and A549/DOX cells, thus resulting as promising P-gp-mediated MDR reverser with a synergistic mechanism. Furthermore, compounds 13, 27 and 32 induced collateral sensitivity (CS) in MDR cells, as they were more cytotoxic in resistant cells than in the sensitive ones; their CS mechanisms were extensively investigated. [ABSTRACT FROM AUTHOR]

Background: To overcome the problem of side effects and toxicity, development of new anticancer agents is needed. Recently, piperidine salicylanilide derivatives with nanomolar epidermal growth factor receptor (EGFR) inhibitory and cytotoxicity activity have been reported. In the present study effect of replacing piperidine in reported piperidine salicylanilide with N-methyl piperazine and changing substituent's of phenyl ring at other end on anticancer activity have been explored. A series of sixteen methyl piperazine incorporated phenyl benzamide and phenyl methanone derivatives have been synthesized and tested in a panel of three cancer cell lines (adenocarcinomic human alveolar basal epithelial cells (A-549), human colon carcinoma (HCT-116) and human pancreatic carcinoma (MIAPaCa-2)), using gefitinib as standard. Further, to study the probable mechanism, due to their structural similarity with EGFR inhibitors, docking interactions with EGFR active site were observed using Schrodinger suite. Result: The results indicated that most of the compounds showed promising activity; out of which, compound A-11 was most active having cytotoxicity much better than that of gefitinib. It showed IC50 value of 5.71 µM against A-549 cell line, 4.26 µM against HCT-116 colon cancer line and 31.36 µM against MIAPaCa-2 cell line. Conclusion: It was found that these compounds fit well in the active site and may be exhibiting anticancer activity via EGFR inhibition. [ABSTRACT FROM AUTHOR]

A series of novel vindoline–piperazine conjugates were synthesized by coupling 6 N-substituted piperazine pharmacophores at positions 10 and 17 of Vinca alkaloid monomer vindoline through different types of linkers. The in vitro antiproliferative activity of the 17 new conjugates was investigated on 60 human tumor cell lines (NCI60). Nine compounds presented significant antiproliferative effects. The most potent derivatives showed low micromolar growth inhibition (GI50) values against most of the cell lines. Among them, conjugates containing [4-(trifluoromethyl)benzyl]piperazine (23) and 1-bis(4-fluorophenyl)methyl piperazine (25) in position 17 of vindoline were outstanding. The first one was the most effective on the breast cancer MDA-MB-468 cell line (GI50 = 1.00 μM), while the second one was the most effective on the non-small cell lung cancer cell line HOP-92 (GI50 = 1.35 μM). The CellTiter-Glo Luminescent Cell Viability Assay was performed with conjugates 20, 23, and 25 on non-tumor Chinese hamster ovary (CHO) cells to determine the selectivity of the conjugates for cancer cells. These compounds exhibited promising selectivity with estimated half-maximal inhibitory concentration (IC50) values of 2.54 μM, 10.8 μM, and 6.64 μM, respectively. The obtained results may have an impact on the design of novel vindoline-based anticancer compounds. [ABSTRACT FROM AUTHOR]

A six-membered heterocyclic compound known as piperazine has two nitrogen atoms within a ring. Numerous studies have shown that piperazine has the potential to be a useful pharmacophore in many harmful pharmacological conditions, such as microbiocidal, anti-inflammatory, anticancer, antioxidant, etc. In this present review, we highlighted the synthetic protocols for piperazine and its analogs and the synthetic protocol for piperazine via rearrangement reactions that have been adopted in recent years. The study also involved a listing of several patents (granted), which comprised important work on piperazine and its derivatives. Among all the methods, the most commonly adopted synthetic methods included the synthesis of piperazine analogs by diaza-cope, hydrolytic, Mumm, Ugi-smiles, [2 + 3] Stevens, Aza-witting, Curtius, Schmidt rearrangement reactions, etc. These synthetic protocols have also been compared based on different reaction conditions, feasibility, and economy to help the researchers in designing their work. [ABSTRACT FROM AUTHOR]

Diabetes mellitus is a severe endocrine disease that affects more and more people every year. Modern medical chemistry sets itself the task of finding effective and safe drugs against diabetes. This review provides an overview of potential antidiabetic drugs based on three heterocyclic compounds, namely morpholine, piperazine, and piperidine. Studies have shown that compounds containing their moieties can be quite effective in vitro and in vivo for the treatment of diabetes and its consequences. [ABSTRACT FROM AUTHOR]

In this study, protonation constant values and liquid chromatographic behaviors of hydrophobic cyclizine, chlorcyclizine, hydroxyzine, cinnarizine, cetirizine, meclizine, and buclizine in some water‐organic solvent binary mixtures were examined for the first time using classical and green reverse phase liquid chromatography methods. In the isocratic study, the relationship of the retention time and mobile phase pH in water‐organic solvent binary mixtures containing acetonitrile (45, 50, 55, 60, 65%, v/v), methanol (60, 65, 70, 75%, v/v) and ethanol (45, 50, 55, 56, 59, 60, 62, 65%, v/v) were determined at 37 °C. In the study, XBridge C18 and Gemini NX C18 columns suitable for the chemical properties of basic compounds were used. The obtained liquid chromatographic data were analyzed using the linear solvation energy relationship methodology and the SOLVER program. The aqueous protonation constant values of the investigated compounds were calculated using the linear relationship between the protonation constant data calculated in studied binary mixtures and some macroscopic constant values of the solvents used. The greenness of methods developed using three different solvents was evaluated with the Analytical Greenness Metric Approach, the Green Analytical Procedures Index, and the Green Solvent Selection Tool approaches. [ABSTRACT FROM AUTHOR]

Compared to conventional monoethanolamine (MEA), alternative solvents are expected to substantially contribute to reduce the energy demand of postcombustion CO2 capture from flue gases. This study presents a comprehensive techno-economic analysis of a 27wt% 2-amino-2-methyl-1- propanol (AMP) + 13wt% piperazine (PZ) aqueous solution for CO2 capture, compared to a 30 wt% MEA solution. The study addresses the retrofit of a carbon capture unit to a biomass-fired combined heat and power (CHP) plant, effectively making it a bioenergy with a carbon capture and storage (BECCS) system. The treated flue gas has a flow rate of 23 tons/hour (t/h) with 11.54 vol% CO2 and a 90% capture rate is aimed for. Aspen Plus V14 was employed for process simulations. Initially, binary interaction parameters for AMP/PZ, AMP/H2O, and PZ/H2O are regressed using vapor-liquid equilibrium (VLE) data, which were retrieved from literature along with reaction kinetics. Validation of parameters from available experimental literature yields an average absolute relative deviation (AARD) of only 5.9%. Afterwards, a process simulation model is developed and validated against experimental data from a reference pilot plant, using a similar AMP/PZ blend, resulting in 5% AARD. Next, a sensitivity analysis optimizes operating conditions, including solvent rate, absorber/stripper packing heights, and stripper pressure, based on regeneration energy impact. Optimized results, compared to MEA, reveal that AMP/PZ reduces the energy consumption from 3.61 to 2.86 GJ/tCO2. The retrofitting of the capture unit onto the selected CHP plant is examined through the development of a dedicated model. Two control strategies are compared to address energy unavailability for supplying the capture unit. The analysis spans 4 months, selected to account for seasonal variations. At nominal capacity, CO2 emissions, rendered negative by biomass combustion and CO2 capture, reach a maximum of -3.4 tCO2/h compared to 0.36 tCO2/h before retrofitting. Depending on the control strategy and CHP plant operating point, the Specific Primary Energy Consumption for CO2 Avoided (SPECCA) ranges from 4.91 MJ/kgCO2 to 1.76 MJ/kgCO2. Finally, an economic comparison based on systematic methodology reveals a 7.87% reduction in capture cost favoring the AMP/PZ blend. Together, these findings highlight AMP/PZ as a highly favorable alternative solvent. [ABSTRACT FROM AUTHOR]

Two series of novel hybrid heterocyclic compounds that combine the imidazole ring with bioactive piperidine, morpholine or piperazine heterosystems, through a hydrazone unit, were easily obtained by two competitive pathways. Starting from 5‐amino‐4‐cyanoformimidoyl imidazoles and 1‐aminopiperidine, 4‐aminomorpholine or 1‐amino‐4‐methylpiperazine under mild acidic media led to the selective synthesis of 5‐aminoimidazole 4‐carboxamidrazones, whereas the corresponding 4‐hydrazonoyl cyanide derivatives were obtained under stronger acidic conditions. These highly functionalized imidazoles provide convenient synthetic precursors to a vast array of heterocycles with potential pharmaceutical applications. The reaction mechanisms were elucidated on the basis of experimental assays and in silico calculations. The compounds were screened against colorectal cancer HCT116‐p53 wt cell line, and significant IC50 values of 3.69 μM and 4.83 μM were obtained. [ABSTRACT FROM AUTHOR]

In this study, the synthesis of N‐(5,6‐methylenedioxybenzothiazole‐2‐yl)‐2‐[(substituted)thio/piperazine]acetamide/propanamide derivatives (3a‐3k) and to investigate their acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and β‐secretase 1 (BACE‐1) inhibition activity were aimed. Mass, 1H NMR, and 13C NMR spectra were utilized to determine the structure of the synthesized compounds. Compounds 3b, 3c, 3f, and 3j showed AChE inhibitory activity which compound 3c (IC50 = 0.030 ± 0.001 µM) showed AChE inhibitory activity as high as the reference drug donepezil (IC50 = 0.0201 ± 0.0010 µM). Conversely, none of the compounds showed BChE activity. Compounds 3c and 3j showed the highest BACE‐1 inhibitory activity and IC50 value was found as 0.119 ± 0.004 µM for compound 3j whereas IC50 value was 0.110 ± 0.005 µM for donepezil, which is one of the reference substance. Molecular docking studies have been carried out using the data retrieved from the server of the Protein Data Bank (PDBID: 4EY7 and 2ZJM). Using in silico approach behavior active compounds (3c and 3j) and their binding modes clarified. [ABSTRACT FROM AUTHOR]

The availability of piperidine, which is widely used for deblocking α-amine groups in solid-phase peptide synthesis using Fmoc methodology, is now significantly limited because this reagent is classified as a controlled substance. Therefore, a search for other available reagents capable of removing Fmoc-protection seems relevant. The suitability of three deblocking reagents based on secondary amines (4-methylpiperidine, pyrrolidine, and piperazine) for the solid-phase synthesis of peptides of various structures, i.e., atosiban (an analog of the neurohypophysial hormone oxytocin), metilin [an agonist of the apelin receptor (APJ)], and a fragment of the 11-19 amino-acid segment of the regulatory myosin light chain was comparatively assessed. These reagents were shown to be suitable alternatives to piperidine for the preparation of the physiologically active peptides being studied. [ABSTRACT FROM AUTHOR]

The versatile basic structure of piperazine allows for the development and production of newer bioactive molecules that can be used to treat a wide range of diseases. Piperazine derivatives are unique and can easily be modified for the desired pharmacological activity. The two opposing nitrogen atoms in a six‐membered piperazine ring offer a large polar surface area, relative structural rigidity, and more acceptors and donors of hydrogen bonds. These properties frequently result in greater water solubility, oral bioavailability, and ADME characteristics, as well as improved target affinity and specificity. Various synthetic protocols have been reported for piperazine and its derivatives. In this review, we focused on recently published synthetic protocols for the synthesis of the piperazine and its derivatives. The structure–activity relationship concerning different biological activities of various piperazine‐containing drugs has also been highlighted to provide a good understanding to researchers for future research on piperazines. [ABSTRACT FROM AUTHOR]

Modeling of CO2 removal in a rotating packed bed using a mixed amine solution of piperazine and methyldiethanolamine with various molar concentration ratios was done with Aspen Plus® and dynamically linked with Intel® Visual Fortran. In addition to the mass and energy balances, all the necessary correlations for the rotating packed bed were written in Intel® Visual Fortran. The developed model was validated, and the result showed good agreement with a percentage error of less than 10%. The model was scaled‐up to absorb CO2 from the flue gas composition of a typical 6.4 MWe biomass power plant with the goal of producing net negative CO2 emissions. The effect of process parameters such as temperature, rotation speed, liquid‐gas ratio, methyl diethanolamine concentration, and piperazine concentration on capture efficiency and regeneration energy was investigated. It was discovered that increasing the rotational speed results in an improvement in the separation efficiency. Increasing the temperature of the lean solvent causes a decrease in separation efficiency, which is due to a decrease in solubility as the temperature increases. Increasing the liquid‐to‐gas ratio leads to an increase in CO2 absorption efficiency because more hydroxide ions are present to react with the CO2. Piperazine is a reactive compound and increasing its concentration in the mixed solvent leads to an increase in CO2 absorption efficiency. Finally, the results of the study demonstrated that a solvent mixture consisting of piperazine and methyldiethanolamine has the potential to be utilized in post‐combustion CO2 capture using rotating packed bed technology. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

BACKGROUND: Xanthomonas oryzae pv. oryzae (Xoo) is often considered one of the most destructive bacterial pathogens causing bacterial leaf blight (BLB), resulting in significant yield and cost losses in rice. In this study, a series of novel derivatives containing the isopropanolamine moiety linked to various substituted phenols and piperazines were designed, synthesized and screened. RESULTS: Antibacterial activity results showed that most compounds had good inhibitory effects on Xoo, among which compound W2 (EC50 = 2.74 μg mL−1) exhibited the most excellent inhibitory activity, and W2 also had a certain curative effect (35.89%) on rice compared to thiodiazole copper (TC) (21.57%). Scanning electron microscopy (SEM) results indicated that compound W2 could cause rupture of the Xoo cell membrane. Subsequently, proteomics and quantitative real‐time polymerase chain reaction revealed that compound W2 affected the physiological processes of Xoo and may exert antibacterial activity by targeting the two‐component system pathway. Interestingly, W2 upregulated Xoo's methyltransferase to impact on its pathogenicity. CONCLUSION: The present study offers a promising phenolic‐piperazine‐sopropanolamine compound as an innovative antibacterial strategy by specifically targeting the two‐component system pathway and inducing upregulation of methyltransferase to effectively impact Xoo's pathogenicity. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Amine‐scrubbing‐based chemical absorption remains a prominent CO2 capture process. However, the overall efficiency of conventional amine absorbents is hard to meet the ever‐increasing demands for CO2 capture. Consequently, developing powerful absorbents for efficient and cost‐effective CO2 capture is greatly important but challenging. Here, a new type of amine absorbent with improved solubility and stability was achieved by substituting the secondary amino groups in piperazine (PZ) with aminoethyl and hydroxyalkyl moieties. The developed amine absorbent presents superior CO2 absorption/desorption abilities through the synergy of their intramolecular amines, leading to a low regeneration energy consumption of 2.56 GJ·t−1 CO2. Moreover, the enhancement of CO2 capture and the corresponding mechanism were elucidated using density functional theory calculations and nuclear magnetic resonance analysis. Such newly developed amine absorbent with excellent CO2 capture performance are expected to greatly contribute to ongoing efforts toward carbon neutrality. [ABSTRACT FROM AUTHOR]

The cholinergic hypothesis is one of the hypotheses of Alzheimer's disease that shows the relationship between the onset and progression of the disease. One of the main ways to increase the level of acetylcholine is to inhibit cholinesterase enzymes. The benzimidazole core is very important in medicinal chemistry research due to its high affinity to various enzymes and protein receptors. The present study was conducted in the synthesis of benzimidazole derivatives with the aim of investigating butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) inhibitory activity. In the first step of experimental study, the product 2-(chloromethyl)benzimidazole (2) was obtained, then the final three benzimidazole derivatives 3, 4, and 5 were synthesized from the reaction of 1 mmol 2-(Chloromethyl)benzimidazole and 1 mmol of piperazine or N-phenylpiperazine, and 2- phenylethan-1-amine, respectively. The structure of the prepared compounds was confirmed by 1H-NMR, 13C-NMR, and FT-IR spectroscopic methods. The ability of the compounds to inhibit AChE and BuChE was evaluated using Ellman's assay. The obtained results showed the significant inhibitory activities of these compounds. Among them, compound 5 with IC50 = 0.28 μM showed the highest inhibition against BuChE enzyme. The inhibitory activity of compound 5 against BuChE was more than donepezil as a standard drug. In addition, the interaction of compound 5, galantamine, and rivastigmine with BuChE enzyme was investigated using docking studies. In these studies, compound 5 with an energy value of -8.88 kcal/mol showed the best interaction with the active site of the receptor. According to the obtained results, compound 5 is the most promising compound for the development of benzimidazole derivatives against Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Novel pyrrolo[2,3-d]pyrimidine-based analogues were designed, synthesized, and evaluated for their ability to inhibit the α-amylase enzyme in order to treat diabetes. In vitro antidiabetic analysis demonstrated excellent antidiabetic action for compounds 5b, 6c, 7a, and 7b, with IC50 values in the 0.252–0.281 mM range. At a 200 μg/mL concentration, the exceptional percent inhibition values for compounds 5a, 5b, 5d, and 6a varied from 97.79 ± 2.86% to 85.56 ± 4.13% overperforming the standard (acarbose). Molecular docking of all compounds performed with Bacillus paralicheniformis α-amylase enzyme. The most active compounds via in vitro and non-toxic via in silico ADMET and molecular docking analysis, hybrids 6c, 7a, and 7b displayed binding affinity from − 8.2 and − 8.5 kcal/mol. Molecular dynamic simulations of most active compound 5b and 7a investigated into the active sites of the Bacillus paralicheniformis α-amylase enzyme for a 100-ns indicating the stability of hybrid-protein complex. Consistent RGyr values for the two complexes under study further suggest that the system's proteins are closely packed in the dynamic state. Synthesized analogs' in vitro biological assessments, ADMET, molecular docking, and MD modelling reveal that 5b, 6c, 7a, and 7b hybrid analogs may be employed in the development of future antidiabetic drugs. [ABSTRACT FROM AUTHOR]

In this research paper, an investigation has been made to assess the simultaneous effect of a solubility enhancement approach, i.e., hydrotropy on the solubility and apparent permeability of piroxicam. The solubility of piroxicam (PRX) a BCS (biopharmaceutics classification system) class II drug has been increased using a mixed hydrotropy approach. This study is based on identifying the pattern of solubility-permeability interplay and confirming whether every solubility gain results in a concomitant decrease in permeability or permeability remains unaffected. Solid dispersions of PRX were formulated using two hydrotropes, viz., sodium benzoate (SB) and piperazine (PP) by solvent evaporation method. A comprehensive 32factorial design was employed to study the effect of hydrotropes on the solubility and permeability of PRX. Subsequently, PRX tablets containing these solid dispersions were formulated and evaluated. SB and PP displayed a significant increase in the solubility of PRX ranging from 0.99 to 2.21 mg/mL for F1–F9 batches attributed to the synergistic effect of hydrotropes. However, there is a reduction in PRX permeability with increasing hydrotrope levels. The decline in permeability was notably less pronounced compared to the simultaneous rise in aqueous solubility of PRX. An evident tradeoff between permeability and solubility emerged through the mixed hydrotropic solubilization for PRX. As PRX has generally higher intrinsic permeability, it has been assumed that this permeability loss will not affect the overall absorption of PRX. However, it may affect the absorption of drugs with limited permeability. Therefore, solubility permeability interplay should be investigated during solubility enhancement. [ABSTRACT FROM AUTHOR]

Cytochrome P450 (CYP450)‐catalyzed oxidative coupling is an efficient strategy for using simple building blocks to construct complex structural scaffolds of natural products. Among them, heterodimeric coupling between two different monomers is relatively scarce, and the corresponding CYP450s are largely undiscovered. In this study, we discovered a fungal CYP450 (CpsD) and its associated cps cluster from 37208 CYP450s of Pfam PF00067 family member database and subsequently identified a group of new skeleton indole piperazine alkaloids (campesines A−G) by combination of genome mining and heterologous synthesis. Importantly, CYP450 CpsD mainly catalyzes intermolecular oxidative heterocoupling of two different indole piperazine monomers to generate an unexpected 6/5/6/6/6/6/5/6 eight‐ring scaffold through the formation of one C−C bond and two C−N bonds, illuminating its first dimerase role in this family of natural products. The proposed catalytic mechanism of CpsD was deeply investigated by diversified substrate derivatization. Moreover, dimeric campesine G shows good insecticidal activity against the global honeybee pest Galleria mellonella. Our study shows a representative example of discovering new skeleton monomeric and dimeric indole piperazine alkaloids from microbial resources, expands our knowledge of bond formation by CYP450s and supports further development of the newly discovered and engineered campesine family compounds as potential biopesticides. [ABSTRACT FROM AUTHOR]

The catalytic activity of zinc(II) compounds was exploited in the nucleophilic addition of amines to nitriles to form amidines. The reaction systems comprised a Zn(II) starting material [Zn(quin)2(H2O)] (quin− = quinaldinate, an anion of quinaldinic acid), secondary cyclic amine, acetonitrile, and in some cases, methanol. Amines with additional heteroatoms in the ring (thiomorpholine, piperazine) or ring substituents (piperidine derivatives, piperazine derivatives) with different steric and electronic effects were used. The aim of the study was to determine how the nature of the amine affects the formation of amidines. Different types of Zn(II) products were obtained: mono- or diamine complexes, amidine complexes, and also an ionic compound with a protonated amine. In one case, the amidine itself crystallized. A Zn(II) complex with acetamidine was also obtained. Acetamidine was formed from acetonitrile and ammonia, which most likely originated from the hydrolysis of acetonitrile under harsh reaction conditions. The hydrolysis could terminate at the acetamide step, which was confirmed by the isolation of a cocrystal containing acetamide. In the case of piperazine (pz), a polymeric compound with the composition [Zn(quin)2(pz)]n was isolated regardless of the reaction conditions. The same coordination polymer was also observed to form in 1-methylpiperazine, 1-ethylpiperazine, and 1-acetylpiperazine reaction systems, containing piperazine as an inherent impurity. This was unambiguously confirmed by the crystal structure of a cocrystal, [Zn(quin)2(1-Acpz)2]·[Zn(quin)2(pz)]n·4CH3CN, which formed in the 1-acetylpiperazine (1-Acpz) reaction system. [ABSTRACT FROM AUTHOR]

Four extracts of the marine-derived fungus Penicillium velutinum J.F.H. Beyma were obtained via metal ions stress conditions based on the OSMAC (One Strain Many Compounds) strategy. Using a combination of modern approaches such as LC/UV, LC/MS and bioactivity data analysis, as well as in silico calculations, influence metal stress factors to change metabolite profiles Penicillium velutinum were analyzed. From the ethyl acetate extract of the P. velutinum were isolated two new piperazine derivatives helvamides B (1) and C (2) together with known saroclazin A (3) (4S,5R,7S)-4,11-dihydroxy-guaia-1(2),9(10)-dien (4). Their structures were established based on spectroscopic methods. The absolute configuration of helvamide B (1) as 2R,5R was determined by a combination of the X-ray analysis and by time-dependent density functional theory (TD-DFT) calculations of electronic circular dichroism (ECD) spectra. The cytotoxic activity of the isolated compounds against human prostate cancer PC-3 and human embryonic kidney HEK-293 cells and growth inhibition activity against yeast-like fungi Candida albicans were assayed. [ABSTRACT FROM AUTHOR]

Modification of membranes is widely used for altering their separation properties. In this study, the modification of PVDF nanofiber mat by deposition of polyamide layers was evaluated to improve dye recovery by means of forward osmosis process. The polyamide active layer was prepared by a reaction of cyclic aromatic amines, m-phenylenediamine, or piperazine, and trimesoylchloride. The modification progress was monitored by FTIR analysis, water uptake, nitrogen content, and grafting yields. Investigated membranes showed an excellent dye separation features with water flux and dye fluxes strongly related to type of applied amines and reaction time. The best obtained membrane demonstrated outstanding performance in forward osmosis; their water flux was 3.3 LMH and rejection rate of 97% for bromocresol green dye. The membrane allowed increase dye concentration by 50% after 24 h of the process. [ABSTRACT FROM AUTHOR]

We report the discovery and biosynthesis of new piperazine alkaloids‐arizonamides, and their derived compounds‐arizolidines, featuring heterobicyclic and spirocyclic isoquinolone skeletons, respectively. Their biosynthetic pathway involves two crucial non‐heme iron enzymes, ParF and ParG, for core skeleton construction. ParF has a dual function facilitating 2,3‐alkene formation of helvamide, as a substrate for ParG, and oxidative cleavage of piperazine. Notably, ParG exhibits catalytic versatility in multiple oxidative reactions, including cyclization and ring reconstruction. A key amino acid residue Phe67 was characterized to control the formation of the constrained arizonamide B backbone by ParG. [ABSTRACT FROM AUTHOR]

Herein, a novel series of 1,5‐disubstituted‐1,2,3‐triazolines containing 1‐(4‐chlorobenzhydryl) piperazine moiety (8–18) were synthesised and evaluated for their anticancer activity across eight human tumor cell lines. Remarkably, compound 11 substituted with 3‐acetylphenyl group was the most potent anticancer agent against three selected human cancer cell lines (HL‐60, Z138, and DND‐41) with IC50 values of 16.80, 18.50, and 19.20 μM, respectively. In contrast, analogue 10 demonstrated activity against HL‐60, Z138, and DND‐41 cell lines, with IC50 values of 19.90, 18.00, and 18.50 μM, respectively. Moreover, derivative 13 substituted with 4‐bromophenyl moiety displayed activity with IC50=19.90 μM against the DND‐41 cell line. However, all analogues showed IC50 values ranging from 22.95 to 58.45 μM when tested against other investigated cancer cell lines. These findings suggest that derivative 11 holds promise as a potential candidate for synthesizing novel anticancer agents. Furthermore, compounds 8–18 were screened for their antioxidant activity. Molecular docking studies of compound 11 on crystal structures of two proteins, CDK2/cyclin A2 (PDB: 7B7S) and kinase Akt1 PKB alpha (PDB: 4GV1) have been studied. [ABSTRACT FROM AUTHOR]

Two typical Cu-based complex catalysts with piperazine (PR) and p-phenylenediamine (pPDA) ligands were designed to elucidate whether the ligands can tailor the reduction behavior of the Cu species and thus modulate their electrochemical CO2 reduction reaction (eCO2RR) activity. Specifically, Cu-PR underwent a significant in situ transformation into Cu nanoparticles enriched with a Cuδ+/Cu0 interface for high eCO2RR activity, compared to Cu-pPDA. This finding reveals the importance of ligand engineering in modulating the eCO2RR performance of Cu-based complexes. [ABSTRACT FROM AUTHOR]

This article discusses a new method for synthesizing 5-dialkylamino-1,2,4-oxadiazoles, which are important in drug discovery. The method involves using tertiary amines as temporary masked secondary amines, allowing for the direct construction of these compounds in a one-pot manner. The research provides a more efficient and facile approach for synthesizing these compounds, which have potential therapeutic applications. The article also provides detailed information on the synthesis and characterization of various N,N-dialkylamino-substituted 1,2,4-oxadiazoles, as well as piperazine-linked 1,2,4-oxadiazoles. The research was conducted at Chiang Mai University in Thailand and is supported by the university. [Extracted from the article]

Piperazine pyrophosphate (PPAP) was compounded with a variety of flame retardants to prepare intumescent flame retardant (IFR), and finally blended with polypropylene (PP) to prepare PP flame retardant composites. These composites were characterized by vertical combustion, limiting oxygen index (LOI), cone calorimetry, thermogravimetric analysis and mechanical properties. The results show that compared with PP samples, the LOI of these composites increases from 17.6% to more than 26%, the carbon residue rate increases from 0.09% to more than 1.98%, and the thermal decomposition T1% and T5% increase by 11.4 °C and 41.2 °C, respectively, indicating that the addition of flame retardant enhanced the flame retardant. At the same time, the peak heat release rate, average heat release, total heat release and total smoke production of these composites are greatly reduced, and the flame retardancy and smoke suppression properties are significantly improved, while the mechanical properties are reduced. The flame retardant effect of PPAP and melamine pyrophosphate (DMPY) is the best, in which the LOI is 29.2%, the carbon residue rate is 2.65%, the thermal decomposition T1% and T5% are 286.6 °C and 372.7 °C, respectively, and the mechanical properties are the least affected. [ABSTRACT FROM AUTHOR]

Two typical Cu-based complex catalysts with piperazine (PR) and p-phenylenediamine (pPDA) ligands were designed to elucidate whether the ligands can tailor the reduction behavior of the Cu species and thus modulate their electrochemical CO2 reduction reaction (eCO2RR) activity. Specifically, Cu-PR underwent a significant in situ transformation into Cu nanoparticles enriched with a Cuδ+/Cu0 interface for high eCO2RR activity, compared to Cu-pPDA. This finding reveals the importance of ligand engineering in modulating the eCO2RR performance of Cu-based complexes. [ABSTRACT FROM AUTHOR]

Although Hantzsch synthesis has been an established multicomponent reaction method for more than a decade, its derivative, whereby an aniline replaces ammonium acetate as the nitrogen source, has not been explored at great length. Recent studies have shown that the products of such a reaction, N-aryl-4-aryldihydropyridines (DHPs), have significant anticancer activity. In this study, we successfully managed to synthesize a wide range of DHPs (18 examples, 8 of which were novel) using a metal-free, mild, inexpensive, recoverable, and biopolymer-based heterogeneous catalyst, known as piperazine, which was supported in agar–agar gel. In addition, 8 further examples (3 novel) of such dihydropyridines were synthesized using isatin instead of aldehyde as a reactant, producing spiro-linked structures. Lastly, this catalyst managed to afford an unprecedented product that was derived using an innovative technique—a combination of multicomponent reactions. Essentially, the product of our previously reported aza-Friedel–Crafts multicomponent reaction could itself be used as a reactant instead of aniline in the synthesis of more complex dihydropyridines. [ABSTRACT FROM AUTHOR]

It is well known that daidzein has various significant medicinal values and health benefits, such as anti-oxidant, anti-inflammatory, anti-cancer, anti-diabetic, cholesterol lowering, neuroprotective, cardioprotective and so on. To our disappointment, poor solubility, low permeability and inferior bioavailability seriously limit its clinical application and market development. To optimize the solubility, permeability and bioavailability of daidzein, the cocrystal of daidzein and piperazine was prepared through a scientific and reasonable design, which was thoroughly characterized by single-crystal X-ray diffraction, powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. Combining single-crystal X-ray diffraction analysis with theoretical calculation, detailed structural information on the cocrystal was clarified and validated. In addition, a series of evaluations on the pharmacogenetic properties of the cocrystal were investigated. The results indicated that the cocrystal of daidzein and piperazine possessed the favorable stability, increased solubility, improved permeability and optimized bioavailability of daidzein. Compared with the parent drug, the formation of cocrystal, respectively, resulted in 3.9-, 3.1-, 4.9- and 60.8-fold enhancement in the solubility in four different media, 4.8-fold elevation in the permeability and 3.2-fold in the bioavailability of daidzein. Targeting the pharmaceutical defects of daidzein, the surprising elevation in the solubility, permeability and bioavailability of daidzein was realized by a clever cocrystal strategy, which not only devoted assistance to the market development and clinical application of daidzein but also paved a new path to address the drug-forming defects of insoluble drugs. [ABSTRACT FROM AUTHOR]

Amine solvents remain popular in the industries for post combustion carbon dioxide (CO2) capture. Dissociation constant of basic amine solvents plays significant role to influence the CO2 absorption. It is thus important to study the dissociation of new amine solvents for assessing their viability for CO2 capture. In the present work, potentiometric titration method is employed to determine the dissociation constants of dibasic (e. g. Piperazine (PZ), 1‐methyl piperazine (1‐MPZ) and tribasic amines (1‐(2‐aminoethyl‐piperazine) (AEPZ) which could be promising for formulating blended solvent system towards enhancing the rate of CO2 absorption. The estimated dissociation constants for the PZ and 1‐MPZ while match well with reported results, the dissociation constants for AEPZ has been determined newly here within the temperature range 298—318 K. In addition, the structural geometric parameters and Natural Bond Order (NBO) calculations of the amine solvents are performed based on Density Functional Theory (DFT). The NBO calculations predict charge distribution on the nitrogen and other elements, and envisage its effect on the pKa values of the amines. Further, potential energy surface (PES) scanning calculations are performed for AEPZ to explain it's ring inversion which is responsible for obtaining a single pKa value in experimental studies. [ABSTRACT FROM AUTHOR]

A new layered metal sulfide, namely (C6H15N3)1.3(NH4)1.5H1.5In3SnS8 (1, C6H15N3 = N-(2-aminoethyl) piperazine), has been solvothermally synthesized and characterized. Compound 1 crystallizes in the monoclinic space group C2/c. Its structure features a two-dimensional layer of {In3SnS8}n3n− with the (4,4) topology net, which is formed by interlinking supertetrahedral T2 clusters as secondary building units. Band structure calculations revealed that 1 had a band gap of 2.7 eV. The photoelectric response of 1 showed steady and reversible on/off cycles with an "on" state of 121.13 nA cm−2. Moreover, the activation of 1 by replacing the sluggish organic cations with harder K+ ions endowed the material with improved adsorption performances for Sr2+ ions from aqueous solutions. [ABSTRACT FROM AUTHOR]