Guanidine Sulfate Research Articles

Effect of Guanidinium Salt for Stress-Relaxation and Interfacial Engineering in Antisolvent Free Perovskite Solar Cells Fabricated Under Air Ambient.

In perovskite solar cells, the presence of stress and defects at interfaces promotes performance degradation and poor stability of the devices. The formation of these defects is more prominent in two-step antisolvent-free perovskite film fabrication. This study addresses these challenges by introducing guanidine sulfate (Gua-S) at the tin oxide/formamidinium lead iodide perovskite interface, fabricated without antisolvent under ambient air. Interfacial Gua-S enhanced morphology by forming bonds between uncoordinated Pb2+ ions and I- vacancies at the interface and showed improvement in the crystallinity and quality of the perovskite film. Microstructural stress analysis indicated a substantial reduction in stress, decreasing from 50.6 to 20.72 MPa with the application of Gua-S. Moreover, the Gua-S treated solar cells showed significant improvements and achieved an open circuit voltage of 1.08 V and 22.34% efficiency. Further, electrochemical impedance spectroscopic analysis showed improved built-in potential, carrier lifetime, and charge recombination lifetime for treated devices. The devices retained over 87% of the initial power conversion efficiency after 2000 hours of operation. This comprehensive study addresses the fundamental issues of interfacial stress and defects in perovskite solar cells and demonstrates the efficacy of Gua-S salt in enhancing both the structural and functional aspects of the antisolvent-free device fabrication process.

Guanidine Derivatives Leverage the Antibacterial Performance of Bio-Based Polyamide PA56 Fibres

Bacterial damage has significantly impacted humanity, prompting the control of harmful microorganisms and infectious diseases. In this study, antibacterial bio-based PA56 fibres were prepared with high-speed spinning using ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA) as the compatibiliser and polypentamethylene guanidine sulphate (PPGS) as the antibacterial agent. The effects of PPGS content on the properties of PA56 draw-textured yarns (DTYs) were investigated. The compatibility between PPGS and PA greatly improved with EMA incorporation. Compared with PA56 fibres, the elongation at break of the sample containing 2.0 wt% EMA and PPGS increased by 25.93%. The inhibition rates of the fibres with 1.0 wt% PPGS against Escherichia coli and Staphylococcus aureus reached over 99.99%. Samples were easily coloured with dyes, exhibiting good colour fastness, regardless of the EMA content. However, the antibacterial performances of dyed DTYs decreased to varying degrees. the inhibition rates of samples of 0.5wt% addition of PPGS against E. coli were reduced from 99.99% to 28.50% and 25.36% after dyeing with Acid Blue 80 and Dispersible Blue 2BLN, respectively. The EMA-modified fibres exhibited the best antibacterial activity after dyeing with neutral gray 2BL. These findings are expected to promote the wider use of biobased PA56 in practical applications that require antibacterial performance and to guide the dyeing process of antimicrobial fibres.

Dual Defect Passivation at the Buried Interface for Printable Mesoscopic Perovskite Solar Cells with Reduced Open-Circuit Voltage Loss.

Numerous defects exist at the buried interface between the perovskite and adjacent electron transport layers in perovskite solar cells, resulting in severe non-radiative recombination and excessive open-circuit voltage (VOC) loss. Herein, a dual defect passivation strategy utilizing guanidine sulfate (GUA2SO4) as an interface modifier is first reported. On the one hand, the SO4 2- preferentially interacts with Pb-related defects, generating water-insoluble lead oxysalts complexes. Additionally, GUA+ diffuses into the perovskite and induces the formation of low-dimensional perovskite. These reactions effectively suppress trap states at the buried interface and perovskite boundaries in printable mesoscopic perovskite solar cells (p-MPSCs), thus increasing the carrier lifetime. Meanwhile, GUA2SO4 optimizes the interface energy band alignment, thus accelerating the charge extraction and transfer at the buried interface. This synergistic effect of trap passivation and interface energy band alignment modulation is strongly demonstrated by an increase in average VOC of 70mV and the power conversion efficiency improvement from 17.51% to 18.70%. This work provides a novel approach to efficiently improve the performance of p-MPSCs through dual-targeted defect passivation at the buried interface.

C(NH2)3]BiCl2SO4: an excellent birefringent material obtained by multifunctional group synergy

A multifunctional group synergistic strategy was proposed to successfully develop an excellent organic–inorganic hybrid guanidine sulfate birefringent material [C(NH2)3]BiCl2SO4.

Hydrothermal synthesis of WO3 nanowires in the presence of guanidine sulfate and its photocatalytic activity

WO3 nanowires were fabricated by a hydrothermal method, which proceeded at 170 °C for 48 h in a solution containing C2H10N6H2SO4 as a dispersant and Na2WO4 as a starting material. The nanowires exhibit a well crystallized one-dimensional structure with 20 nm in diameter and several microns in length. The physicochemical properties of WO3 were compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and UV-vis spectroscopy (UV-Vis). The photoactivity of the as-perpared WO3 nanowires was evaluated through the photodegradation of methylene blue (MB) in aqueous solution. The experimental results demonstrate that addition of C2H10N6H2SO4 salt in the WO3 nanowires synthesis process can enhance its photocatalytic activity obviously.

Microwave Irradiation Assisted Synthesis 4-Hydroxy 3-Iodobenzylguanidine(HIBG)

Meta-iodo benzyl guanidine(MIBG) is an analogue of Noradernalin transmitter. When radiolabelled with 123 I and 131I , used for scan and diagnosis Adernal’s tumor. Labeled MIBG with 131I used in therapy of Neuroblastoma , Pheochromocytoma , Carcinoidsyndome and Neuroendocrine tumors. In our continuing efforts to develop MIBG analogues with higher therapeutic efficacy, we recently evaluated the structure-activity characteristics of several analogues of MIBG. We are interested in developing HIBG analogues containing hydroxyl at the 4-postion oF HIBG.generous of the some groups to activate the aromatic ring of a drug towards electrophilic radiodiodination may have merit .The resistance of HIBG to in vivo radiodiodination and amenability to kit production make it a strong candidate for clinical evaluation as a pheochromocytoma and neuroblastoma localzing agent. Microwave assisted heating under controlled conditions has been shown to be an invaluable technology for organic chemistry and during discovery applications since it often rise yield and dramatically reduce reaction times, typically form days or hours to minutes or even seconds.Microwave Irradiation Assisted Synthesis of HIBG is started to produce 4-methoxybenzylamine. 4-methoxybenzylamine and hydriodic acid are mixed and heated for this purpose. Then under MBR condition 4-Hydroxybenzyl guanidine in sulphate form is prepared with additional Cyanamide and Sulphuric acid. After that Iodination is preformed under MBR condition and 4-Hydroxy-3-iodobenzyl guanidine sulphate formed , that can labeled with 131I and exchange to labeled 4-Hydroxy-3-iodobenzyl guanidine sulphate.

New carbazole-containing chalcones and pyrimidines based thereon: Synthesis and electrochemical study

Condensations of aromatic carbo- and heterocyclic ketones and aldehydes in methanol gave new chalcones containing carbazole fragments, 1,3-diaryl(9-R-9H-carbazol-3-yl)prop-2-en-1-ones. Some of the synthesized chalcones reacted with guanidine sulfate to produce 2-amino-4,6-diarylpyrimidines that are promising materials for the design of light emitting diodes. Study on electrochemical polymerization of both chalcones and pyrimidines derived therefrom showed that almost all the examined substrates give rise to stable colored conjugated polymer films on the surface of working electrode under conditions of cyclic voltammetry.

2-Amino-6-(3,4-ethylenedioxythiophen-2-yl)-4-(2-thienyl)-pyrimidine: Synthesis and properties

In 1988 poly(ethylenedioxythiophene) (PEDOT, BAYETRON P) was synthesized for the first time [5, 6] from ethylenedioxythiophene (EDOT) [7, 8]. The doped polymer showed a high conductivity (about 300 S/cm); its oxidized films were almost transparent and thermally stable. Molecular conductors containing fragments of electron-rich [9–12] and electron-deficient aromatic carboand heterocycles [13–15] in addition to EDOT fragments were prepared. Synthesis of such compounds attracts undoubted interest for the design of light-emitting devices [16]. In the present communication we describe the synthesis of a new heterocyclic compound containing an electron-deficient pyrimidine ring linked to two electron-donating fragments, thiophene and ethylenedioxythiophene rings. The synthetic procedure was based on a convenient approach including initial preparation of 2-acetyl-3,4-ethylenedioxythiophene (II) [8] which was brought into condensation with thiophene-2-carbaldehyde in alkaline medium to obtain previously unknown chalcone III. Cyclization of the latter in the presence of guanidine sulfate in alkaline medium according to the procedure described in [17] gave dihydropyrimidine IV, which was oxidized in situ to target product V.

Aggregation in dilute solutions of high molar mass poly(ethylene) oxide and its effect on polymer turbulent drag reduction

We apply methods of dynamic light scattering (DLS) and fluid mechanics to quantitatively establish the role of aggregation in the turbulent drag reduction of high molar mass poly(ethylene oxide) (PEO) solutions. By means of DLS, we show that the dilute aqueous solutions of high molar mass PEO (Mw∼4×106g/mol) are aggregated and that this aggregate structure can be manipulated by addition of the chaotropic salt guanidine sulfate (GuS) or the divalent salt magnesium sulfate (MgSO4). In aqueous solution, we find Γ∼q2.8±0.1, where Γ is the DLS correlation function relaxation rate and q is the scattering vector. This scaling is consistent with internal motions of a large coil or aggregate. Addition of salt progressively decreases the scaling to Γ∼q2.0±0.1 (at 0.5M of MgSO4) consistent with center-of-mass diffusion of isolated coils. We further find that manipulating the aggregation state of PEO with MgSO4 shifts the critical condition for onset of turbulent drag reduction at dilute concentrations in pipe flow by a factor of 2.5. Because this critical condition is inversely proportional to the viscoelastic relaxation time of the polymer solution, we conclude that the aggregation state and the turbulent drag reduction behavior of PEO are strongly correlated. This correlation definitively confirms prior speculation (Cox et al. Nature 1974;249; Vlachogiannis et al. Physics of Fluids 2003;15(12)) that the high molar mass PEO commonly used in literature studies of turbulent drag reduction is in a state of aggregation. Furthermore, the quantitative differences in quiescent DLS characterization and turbulent flow pressure drop measurements suggest that high molar mass PEO undergoes flow-induced de-aggregation in transport systems with shear stresses as low as 0.5Pa.

Reactions of Alkyl 2‐Benzylidene‐2‐polyfluoroacylacetates with N,N‐Dinucleophiles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Reactions of alkyl 2-benzylidene-2-polyfluoroacylacetates with N,N-dinucleophiles

Alkyl 2-benzylidene-2-polyfluoroacylacetates react with urea and thiourea to yield 5-ethoxycarbonyl-4-fluoroalkyl-4-hydroxy-6-phenylhexahydropyrimidin-2-ones and -2-thiones and with guanidine sulfate to form 2-amino-5-ethoxycarbonyl-4-fluoroalkyl-6-phenyl-1,6-dihydropyrimidines and 3,6-diethoxycarbonyl-2,7-difluoroalkyl-4,5-diphenyl-4,5-dihydro-1H-pyrido[1,2-a]pyrimidines, and they react with phenylhydrazine to afford 4-alkoxycarbonyl-3-fluoroalkyl-3-hydroxy-1,5-diphenylpyrazolidines. Hydrazine hydrate catalyzes the formation of 3,5-diethoxycarbonyl-2,6-difluoroalkyl-2,6-dihydroxy-4-phenyltetrahydropyrans. When treated with anhydrous hydrazine and o-phenylenediamine, these esters cleave to form the products of condensation of fluoroacyl ester and benzaldehyde with diamines.

Mineralization of guanidine derivatives in soils

Mineralization of eleven guanidine derivatives was studied in three soils of varying levels of microbial biomass C to evaluate their potential as fertilizer N sources. The guanidines mineralized slowly. Their mineralization generally started after a lag phase which increased with concentration. Mineralization of dimethylguanidine sulphate was the fastest (7–63 days) and tetramethyl guanidine slowest (>98 days) in all soils and at concentrations equivalent to 100 and 500 μg N g-1 soil. The mineralization rates increased with concentration except for guanidine hydrochloride, guanidine thiocyanate, nitroguanidine, and tetramethyl guanidine. They mineralized faster in soils with higher microbial biomass C. The mineralization of guanidines may be classified into four groups: rapidly mineralized (dimethyl guanidine sulphate); mineralized after a lag phase (guanidine sulphate, guanidine carbonate, guanidine acetate, guanidine hydrochloride and guanidine thiocyanate); a fraction of applied N rapidly mineralized with the gradual mineralization of the remaining N (guanidine nitrate, aminoguanidine nitrate, aminoguanidine carbonate); and very slowly mineralized (nitroguanidine, tetramethyl guanidine). None of the guanidines inhibited germination of wheat and excepting guanidine hydrochloride which reduced growth or guanidine thiocyanate that killed seedling, other guanidines increased the dry matter production.

Radiation-induced isomerization of thiourea into ammonium thiocyanate

The products of γ-radiolysis of solutions of thiourea are reported to be ammonia, sulfur, cyanamide, dicyanamide, and possibly guanidine sulfate. Ammonium thiocyanate, the product of isomerization, has not been observed although it is found to be one of the products in the themal decomposition of aqueous solutions of thiourea over the temperature range of 100–180°C. Hence, the observation of a close to 1% yield of the isomerization product in a 6.25% (0.82M) solution of thiourea, at neutral pH on exposure to γ-radiation from a60Co suurce at room temperature, would appear to be a result of interest in radiation chemistry. This paper present results on the variation of the yield of the isomerization product with the γ-dose. The experiments consisted in irradiating 2 ml of 0.82M aqueous solution of thiourea at neutral pH and under normal atmospheric conditions, i.e., at room temperature and with dissolved air present. The source of radiation was a 2.5 kCi (nominal)60Co source. The method used to detect and measure the isomerization product, ammonium thiocyanate was based on the well-known color reaction between CNS− and Fe+3 monitored spectrophotometrically at 450 nm, after obtaining the calibration curve of absorbance and concentration of NH4CNS. The yield of NH4CNS, expressed as\(G_{NH_4 CNS} \) was 0.083 molecules of NH4CNS for 100 eV absorbed. A suitable mechanism for the process of isomerization is suggested involving the hydrated electroneaq, the major primary product of water radiolysis. The mechanism is consistent with the observed effect of the addition of acetone, a well-known electron scavenger. This suppressed the yield NH4CNS by about 25%.

Stimulation of macrophage colony-stimulating factor synthesis by interleukin-1

Interleukin-1 (IL-1), which plays an important role in the inflammatory response, was found to induce colony-stimulating factor-1 (CSF-1) expression in the MIA PaCa-2 cells. IL-1-induced CSF-1 production was markedly suppressed (70%) by pertussis toxin. This inhibition by pertussis toxin was reversed by benzamide, an inhibitor of ADP-ribosylation reactions. Similarly, IL-1-induced CSF-1 production was inhibited by cholera toxin and this inhibition was reversed by an arginine analog, p-methoxybenzylaminodecamethylene guanidine sulfate. Dibutyryl-cAMP as well as other cAMP elevating agents such as theophylline and forskolin also suppressed IL-1-induced CSF-1 production, suggesting that cAMP concentrations inversely regulate the biosynthesis of CSF-1. Measurement of cAMP concentration indicated that IL-1 treatment of MIA PaCa-2 cells did not change the cAMP level. IL-1-induced CSF-1 production was not suppressed by the protein kinase C (PKC) inhibitor, H7, under conditions in which 12- O-tetradecanoylphorbol-13-acetate-induced CSF-1 production was completely abolished. These data suggest that IL-1-induced CSF-1 production is not mediated via the activation of PKC. Analysis of oncogene c-fos and c-jun expression has shown the enhancement of expression of both protooncogenes prior to CSF-1, suggesting that the expression of these two oncogenes may be the mechanism which triggers CSF-1 gene expression.

Guanidine sulphate: Slow release of mineral nitrogen during incubation in soil

Abstract Guanidine sulphate (GS) was tested as a N fertilizer and nitrification inhibitor in an incubation (25°C) experiment with two soils (Typic Cryoboralf and Typic Cryoboroll). For each soil GS was applied at 0, 5, 15, and 45 μg N g‐1 soil with and without ammonium sulphate (AS) at 0 and 100 μg N g‐1 soil. The GS and AS were placed in bands or mixed into the soil, and incubation was made for 12, 24, 36, and 48 days. GS had a slight effect in slowing nitrification of AS when the GS was applied at 45 μg N g‐1, but banding of AS (with or without GS) was much more effective in slowing nitrification. The release of mineral N (NH4‐N and NO3‐N) from GS was greatly delayed at the 12 and 24 day samplings. At the 36 and 48 days, the apparent proportions of mineral N derived from the GS and AS were much the same. Placing GS in bands, as compared to mixing into the soil, delayed mineralization of N. On Soil 1, for example, the extent of mineralization of GS at 12 and 24 days was 2 and 27%, respectively, for bandi...

Degradation of nitroguanidine wastewater components in soil

The degradation of nitroguanidine (NQ) wastewater components was studied using continuous-flow and perfusion soil columns. After 271 d of operation of the continuous-flow columns and 84 d of operation of the perfusion columns, only some components of NQ wastewater were completely or partially removed. Guanidine nitrate and sulfate were the most readily transformed. NQ, however, was only partially removed. Carbon supplements enhanced the transformation of both sulfate and NQ. Transformation products included nitrosoguanidine and ammonia, but not cyanoguanidine or melamine. Microbial adaptation to wastewater components was not demonstrated. Based on test data, land application of untreated wastewater is not recommended.

Inhibition of myeloid differentiation by inhibitors of ADP-ribosylation

Inhibitors of ADP-ribosylation inhibited the myeloid differentiation of murine myelomonocytic leukemia WEHI-3BD + cells induced by granulocyte colony-stimulating factor. Benzamide, at 2.0 mM, inhibited 50% of the WEHI-3BD + cell differentiation but had no significant effect on the proliferation. However, benzylaminododecylguanine hydrochloride and p-methoxylbenzylaminodecamethylene guanidine sulfate at 2.0 and 2.2 μM, respectively, inhibited 50% of proliferation but had no effect at all on differentiation. The differential effects of inhibitors provide a model to study the role of ADP-ribosylation in myeloid differentiation.

Far-infrared spectra and a new incommensurate phase transition in ferroelectric guanidine sulphate hexahydrate at low temperature

The behaviour of guanidine aluminium sulphate hexahydrate (GASH) at low temperatures is similar to that of triglycine sulphate (TGS). At 80 K, all GASH samples with thickness 20-8500 mu m appear to be homogeneous from careful far-infrared transmission measurements. At 4 K, for thickness below 200 mu m, the GASH samples are still homogeneous and keep their 80 K absorption coefficient values. For the thickest samples, at 4 K, a surface layer model has to be considered in a first approximation, with a quite transparent bulk and a surface layer that also maintains the 80 K absorption coefficient values. An explanation is suggested for both TGS and GASH in terms of reduction to one formula unit per primitive cell at some temperature T0. The transition should only occur if the sample dimensions are large enough, and it should start from the centre of the sample. From extensive measurements, they have found far-infrared spectroscopic evidence at temperatures T below the transition temperature T0 that both GASH and TGS single crystals have a superstructure where the electric dipole associated with one formula unit is slightly rotated when the primitive cell is translated from the centre to the surface of the sample.

Inhibitors of Cholera Toxin-Induced Adenosine Diphosphate Ribosylation of Membrane-Associated Proteins Block Stem Cell Differentiation

Two potent inhibitors of mono-adenosine diphosphate (ADP) ribosylation have recently been described and characterized, named p-methoxylbenzylaminodecamethylene guanidine sulfate (MBAMG) and benzylaminododecylguanine hydrochloride (BADGH). We have used these agents to investigate the role of ADP ribosylation in hematopoiesis using long-term marrow cultures. The addition of MBAMG (10(-6) mol/L) or BADGH (5 X 10(-4) mol/L) led to both an inhibition of mature cell production and the development of colony-stimulating factor (CSF-1)-responsive GM-CFC, but had no effect upon spleen colony-forming units (CFU-S) or on progenitor cells which respond to the multilineage stimulating factor present in WEHI-3B cell-conditioned medium. These data indicate that these inhibitors of mono-ADP ribosylation can block the commitment and/or differentiation of stem cells and infers that ADP ribosylation may be of some importance in the hematopoietic process.

Carbon‐14 and tritium labeled guanadrel sulfate

AbstractCarbon‐14 and tritium labeled (1,4‐dioxaspiro[4.5]dec‐2‐ylmethyl)guanidine sulfate, or guanadrel sulfateGuanadrel sulfate is the USAN name for (1,4‐dioxaspiro[4.5]dec‐2‐ylmethyl) guanidine sulfate. (1) were synthesized. The carbon‐14 label was incorporated into the dioxolane ring portion of guanadrel sulfate. The tritium labels were introduced into the cyclohexane ring portion of the molecule, at the beta and gamma positions with respect to the ketal linkage. The ketal resulting from the reaction of the original 2‐cyclohexen‐1‐one with 3‐phthalimido‐1,2‐propanedial contained a double bond in the β‐γ position rather than the α‐β postion of the original 2‐cyclohexen‐1‐one. This double bond shift provided a convenient method of introducing tritium into the 3‐and 4‐positions of cyclohexanone. Proof of the double bond position is discussed.