Cl Atoms Research Articles

First-principles predictions of corrosion resistance of (0001) surface of Co and Co3X (X = Cr, Ni, Mn) compounds

Based on the first principles, the stability and adsorption properties of (0001) surface of Co and Co3X alloys were studied. The effect of the introduction of Cr, Ni and Mn atoms on the surface energy and work function of the Co (0001) surface is predicted. In addition, the adsorption energies of O atom, H atom, Cl atom, OH group and H2O molecule on the surface of cobalt alloy were predicted. The introduction of Cr and Mn atoms enhanced the adsorption capacity of O atom on its (0001) surface, while the addition of Ni was beneficial to the improvement of surface oxidation resistance. On the (0001) surface of Co and Co3X, the adsorption capacity of O atom is higher than that of other adsorption species.

Experimental, Grand canonical Monte Carlo, and Density Functional Theory studies for comparing halloysite and kaolinite on heavy metals fate during pyrolysis of solid waste

In this study, we utilized low-cost halloysite (Hal) for the first time to enhance the solid-phase enrichment and stability of heavy metals (HMs) during solid waste pyrolysis through experimental and theoretical methods, and compared with kaolinite (Kao). Experimental results demonstrated that Hal was superior to Kao in improving the solid-phase enrichment of HMs. Specifically, the solid-phase enrichment of Cd increased by 32.6 % (500 °C) and 25.94 % (600 °C), while that of Pb and Zn increased by 17.37 %/16.83 % and 19.82 %/22.37 % (700/800 °C), respectively. Adding Hal reduced the proportion of HMs in the unstable fraction (F1 + F2), consequently lowering the environmental risk of biochar and the extractable state of HMs. Through Grand canonical Monte Carlo and Density Functional Theory (DFT) simulations, we analyzed the adsorption amounts, adsorption sites, and adsorption mechanisms of Cd/Pb compound on Hal/Kao surfaces, revealing that the primary factor influencing the adsorption performance of Hal and Kao was the difference in specific surface area. The adsorption amounts of HMs by Hal were significantly higher than Kao and decreased with increasing temperature, while the difference in adsorption performance caused by structural bending was negligible. The DFT results indicated that Cd and Pb monomers were stabilized by establishing covalent bonds with OH or reactive O atoms on the Al-(001) surface, whereas the covalent bonds with ionic bonding properties formed between Cl atoms and unsaturated Al atoms played a crucial role in stabilizing HM chlorides. Furthermore, the adsorption energy of Hal on HMs increased with the removal rate of OH. Our study highlights the potential of Hal in stabilizing HMs during pyrolysis without requiring any modifications, thereby avoiding the generation of modified waste solutions and unnecessary cost loss.

Preparation of Laterally Chloro-Substituted Schiff Base Ester Liquid Crystals: Mesomorphic and Optical Properties

A new class of Schiff base/ester compounds: ICln, 4-((2′-chlorophenylimino)methyl)phenyl-4″-alkoxy benzoates, were synthesized and their mesophase characteristics and thermal behavior were evaluated. Differential scanning calorimetry (DSC) was used to study mesophase transitions, and polarized optical microscopy was carried out to identify the phases (POM). The results show that all compounds are monomorphic, and enantiotropic nematic (N) phases were seen at all side chains. It was found that lateral Cl atoms in the terminal benzene ring influence both conformation and mesomorphic properties. Comparisons between the present investigated lateral Cl derivatives and their laterally neat, as well as their isomeric, compounds have been briefly discussed. Results revealed that the insertion of lateral Cl substituent in the molecular structure impacts the type and stability of the formed mesophases. The exchanges of the ester-connecting moiety improve their thermal nematic stability than their previously prepared structurally isomeric derivatives. These compounds exhibit a broad absorption in the UV-Visible region, including a peak in UV region and a tail around 550 nm, and there were observed to be absorption tail increases and energy band gap decreases with the increase of the alkoxy side chain length. The photoluminescence (PL) intensity was noted to be quenched for the bulky alkoxy group ascribed to non-radiative recombination through the defect states. Moreover, time resolved fluorescence decay spectra reveal that both the radiative and non-radiative recombination lifetime increases with the increase of alkoxy side chain length.

Increase in the Efficiency of the Isotope-Selective Infrared Laser Multiphoton Dissociation of 11BCl3 Molecules in a Mixture with SF6 Serving As a Sensitizer and an Acceptor of Radicals

A strong increase in the efficiency of the isotope-selective infrared laser multiphoton dissociation of 11BCl3 molecules in the natural mixture with 10BCl3 by radiation of a pulsed CO2 laser in the case of admixture of SF6 molecules, which serve as a sensitizer and simultaneously acceptors of radicals, Cl atoms formed in the dissociation of BCl3 molecules, has been detected. The yield and selectivity of dissociation of 11BCl3 molecules increase by several times and the threshold energy density for the dissociation of molecules decreases significantly in the case of their irradiation in the mixture with SF6 compared to irradiation without SF6. This property allows the single-frequency isotope-selective dissociation of 11BCl3 molecules by unfocused laser radiation at a moderate energy density (≈3–5 J/cm2), which is important and relevant for the practical implementation of the laser separation of boron isotopes.

Ca3SiO4Cl2—An Anthropogenic Phase from Burnt Mine Dumps of the Chelyabinsk Coal Basin: Crystal Structure Refinement, Spectroscopic Study and Thermal Evolution

The mineral-like phase Ca3SiO4Cl2, an anthropogenic anhydrous calcium chlorine-silicate from the Chelyabinsk coal basin has been investigated using single-crystal and high-temperature powder X-ray diffraction and Raman spectroscopy. The empirical formula of this phase was calculated as Ca2.96[(Si0.98P0.03)Σ1.01O4]Cl2, in good agreement with its ideal formula. Ca3SiO4Cl2 is monoclinic, space group P21/c, Z = 4, a = 9.8367(6) Å, b = 6.7159(4) Å, c = 10.8738(7) Å, β = 105.735(6)°, V = 691.43(8) Å3. The crystal structure is based upon the pseudo-layers formed by Ca–O and Si–O bonds separated by Cl atoms. The pseudo-layers are parallel to the (100) plane. The crystal structure of Ca3SiO4Cl2 was refined (R1 = 0.037) and stable up to 660 °C; it expands anisotropically with the direction of the strongest thermal expansion close to parallel to the [−101] direction, which can be explained by the combination of thermal expansion and shear deformations that involves the ‘gliding’ of the Ca silicate layers relative to each other. The Raman spectrum of the compound contains the following bands (cm–1): 950 (ν3), 848 (ν1), 600 (ν4), 466 (ν2), 372 (ν2). The bands near 100–200 cm−1 can be described as lattice modes. The compound had also been found under natural conditions in association with chlorellestadite.

Ammonium chloride (–NH3+Cl-) salt formation from dichlorosilane decomposition and its potential impact on silicon nitride atomic layer deposition

Plasma-enhanced atomic layer deposition (PEALD) has been demonstrated to be a promising technique for controlled growth of silicon nitride (SiNx) thin films. Based on first-principles calculations, we present the effects of by-product production on the reaction of dichlorosilane (DCS) as the Si precursor with a hydrogen-terminated N-rich surface created upon ammonia (NH3) plasma treatment relevant to thin film growth. The presence of amines, especially primary amines (–NH2), plays a key role in DCS decomposition by generating H and Cl atoms as by-products. Our work clearly demonstrates that the by-products can be strongly bound to the surface by forming stable –NH3+Cl- complexes, which may in turn affect the SiNx ALD process. The HCl desorption reaction, i.e., –NH3+Cl- → –NH2 + HCl(g), is predicted to be endothermic by 1.1–1.2 eV, depending on HCl surface coverage. The large HCl binding energy suggests that a high thermal energy would be required for its removal from the surface, as evidenced by results from experimental spectroscopic analysis. We also discuss how the by-product presence inhibits DCS adsorption and decomposition, leading to a decrease in the SiNx growth rate.

Increase in the Efficiency of the Isotope-Selective Infrared Laser Multiphoton Dissociation of 11BCl3 Molecules in a Mixture with SF6 Serving As a Sensitizer and an Acceptor of Radicals

A strong increase in the efficiency of the isotope-selective infrared laser multiphoton dissociation of 11BCl3 molecules in the natural mixture with 10BCl3 by radiation of a pulsed CO2 laser in the case of admixture of SF6 molecules, which serve as a sensitizer and simultaneously acceptors of radicals, Cl atoms formed in the dissociation of BCl3 molecules, has been detected. The yield and selectivity of dissociation of 11BCl3 molecules increase by several times and the threshold energy density for the dissociation of molecules decreases significantly in the case of their irradiation in the mixture with SF6 compared to irradiation without SF6. This property allows the single-frequency isotope-selective dissociation of 11BCl3 molecules by unfocused laser radiation at a moderate energy density (≈3–5 J/cm2), which is important and relevant for the practical implementation of the laser separation of boron isotopes.

Direct Chlorination of Ethene on ZnO (0001̅) by Hot Chlorine Atoms

The interaction between ethene and Cl2 on ZnO(0001̅) has been investigated using X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (TPD), and density functional theory (DFT) calculations. At 110 K, the Cl2 molecule is perpendicularly adsorbed on ZnO(0001̅). Upon heating, Cl2 is dissociated on the surface in the temperature range of 200–230 K. When the surface coadsorbed with Cl2 and ethene is heated, the desorption of 1,2-dichloroethane is observed at ∼230 K. The desorption temperature is comparable to the dissociation temperature of Cl2 on ZnO(0001̅). Ethene does not react with Cl atoms chemisorbed on ZnO(0001̅). We propose that “hot” Cl atoms, which are produced during thermal dissociation of Cl2, promote the direct chlorination of C2H4. The energy of the hot Cl atoms is calculated to be maximum 27.5 kcal/mole higher than the energy of the chemisorbed Cl atoms.

Molecular dynamics simulation of the inhibition mechanism of factor XIa by Milvexian-like macrocyclic inhibitors

Factor XIa is an important coagulation factor in the coagulation cascade, and its inhibitors have become a hot topic of research for their potential to block thrombus formation without increasing the risk of bleeding. In this paper, molecular dynamics simulation and binding free energy calculation methods were used to study the inhibition mechanism of five macrocyclic competitive inhibitors, which are the same as the Milvexian nucleus. And the reasons for the different inhibitory abilities of the inhibitors with different substituents in the nucleus were summarized. When the inhibitor has a triazole at the head or a carbamate at the tail, it can enhance the hydrogen bonding or electrostatic interaction with its nearby polar residues. The inhibitor 8 with –CH3 in the tail interacts less with its surrounding residues than the inhibitors 13 and 17 with -CHF2 when both heads carry triazoles. The triazole of inhibitor 17 bears a Cl atom, which can form a strong hydrophobic interaction with the nearby disulfide bond. In addition, the nitrogen atom on the ketone ring of this inhibitor can also increase its interaction with nearby residues. Therefore, inhibitor 17 has the strongest affinity to the protein. The present work has implications for the design of more efficient anticoagulant drugs for FXIa macrocyclic inhibitors.

Highly effective recovery of palladium from a spent catalyst by an acid- and oxidation-resistant electrospun fibers as a sorbent

Palladium is not only a precious metal but also is widely used in catalyst production, therefore it is of significance to recover palladium from spent catalysts. In this paper, Nanofiber modified by 2-Thionicotinic acid (TN-Nanofiber) featuring acid- and oxidation-resistant was fabricated through electrospinning and chemical grafting, which can trap efficiently Pd(II) ions from the extremely acidic and oxidizing systems derived from the leaching of spent catalyst. The adsorption kinetic data of Pd(II) ions was well described by the pseudo-second-order model, and the times required to reach equilibrium was 60 min. The Langmuir isotherm model provided better fitting for the Pd(II) ions adsorption, and the maximum uptake capacity of TN-Nanofiber was evaluated as 348.4 mg/g for Pd(II) ions. Furthermore, the column adsorption experiments proved the feasibility of TN-Nanofiber separation of Pd(II) ions from the spent catalyst. Investigation of the adsorption mechanism demonstrated a planar quadrilateral coordination pattern between the Pd(II) ions and the adsorption sites of TN-Nanofiber, which includes one N and one S atom sourced from the adsorption sites and two Cl atoms derived from the original PdCl42−. In summary, TN-Nanofiber may serve as the next generation of emerging adsorbents to recover palladium from the strongly acidic and oxidizing systems due to its excellent performance.

Crystal Structure, Hirshfeld Surface Analysis, and Computational Study of Quinolin-8-yl 4-Chlorobenzoate: Insights from Spectroscopic, Thermal, and Antitumor Properties

We report the time-efficient synthesis of quinolin-8-yl 4-chlorobenzoate (3) via an O-acylation reaction between 8-hydroxyquinoline (1) and 4-chlorobenzoyl chloride (2) mediated by triethylamine in acetonitrile under heating at 80 °C for 20 min in the Monowave 50 reactor. This protocol is distinguished by its short reaction time, operational simplicity, and clean reaction profile. The structure of 3 was fully characterized through a combination of analytical techniques, including NMR, IR, and UV–Vis spectroscopy, MS spectrometry, differential scanning calorimetry (DSC), thermogravimetry (TG), and crystallographic studies. Interestingly, X-ray diffraction analyses of 3 show that the crystal structure is characterized by C-H···N, C-H···O, Cl···π, and π···π interactions. The molecular conformation presents an orthogonal orientation between aromatic rings in the solid state. The calculated interaction energies using the CE-B3LYP model show that dispersion forces act in a higher proportion to build the crystal, which is consistent with the few short hydrogen interactions detected. Electrostatic potential maps suggest the formation of σ-holes over the Cl atoms. Although they can behave as both Lewis acid and base sites, Cl··Cl interactions are absent due to the shallow depth of these σ-holes. Quantum chemical descriptors and global reactivity descriptors were examined using the B3LYP method with the 6-31G(d,p) basis set implemented in CrystalExplorer. Finally, compound 3 exhibited low activity against HOP-92 and EKVX non-Small-cell lung and UO-31 Renal cancer cell lines, with a growth inhibition percentage (GI%) ranging from 6.2% to 18.1%.

Novel thiourea derivatives against Mycobacterium tuberculosis: synthesis, characterization and molecular docking studies

N-((2-chloropyridin-3-yl)carbamothioyl)thiophene-2-carboxamide (HL1), N-((6-methylpyridin-2-yl)carbamothioyl)thiophene-2-carboxamide (HL2), N-(allylcarbamothioyl)thiophene-2-carboxamide (HL3), 2-chloro-N-(methyl(1-phenylethyl)carbamothioyl)benzamide (HL4) and 2-chloro-N-(bis((R)-1-phenylethyl)carbamothioyl)benzamide (HL5) were synthesized and characterized via FT-IR, 1H-NMR, 13C-NMR and HR-MS techniques and HL3 was characterized via a single crystal X-ray diffraction experiment. The antituberculosis activity of the synthesized thiourea derivatives was tested against the H37RV (ATCC27294), ATCC35822 (INH resistant), ATCC35838 (RIF resistant), ATCC35820 (STM resistant) and ATCC35837 (EMB resistant) standard bacteria strains. The thiourea derivatives were tested on two MDR and one primary drug-sensitive isolates with the microplate nitrate reductase test method. The results indicated that HL2 and HL3 had tuberculosis activity on some of the isolates. It was observed that HL4 was the most effective among all the thiourea derivatives. The interaction mechanism of the synthesized compounds on 2X23, a tuberculosis protein, was investigated via molecular docking method. The interaction was observed to occur over S and Cl atoms in all the compounds. The compounds containing the methyl group were observed to interact via this group.

Molecular Engineering to Tune Functionality: The Case of Cl-Substituted [Fe(terpy)2]2.

The properties of transition-metal complexes and their chemical dynamics can be effectively modified with ligand substitutions, and theory can be a great aid to such molecular engineering. In this paper, we first theoretically explored how substitution with a Cl atom at different positions of the terpyridine ligand affects the electronic structure of the [Fe(terpy)2]2+ complex. We found that besides the substitution at position 4', the next most promising candidate to cause substantial electronic effects is that where the side pyridine ring is substituted at position 5 (β). Therefore, next, we examined in detail the Fe(II) complexes of the 5-chloro and 5,5″-dichloro derivatives of terpy, theoretically and experimentally, to reveal how these substitutions modify the ground state properties and the lifetime of the excited quintet state in such complexes. In addition, we extend the investigation to the complexes of the analogously substituted derivatives of 4'-SMe-terpy. The substitution at position(s) 5 (and 5″) with Cl lowers the energy of the quintet state and increases its lifetime; the results on the 4'-SMe-substituted complexes show similar changes with these two substitutions, verifying that these effects are more or less additive. This study contributes to the enhancement of our molecular engineering toolset for modifying the potential energy landscape of similar complexes.

An Efficient One‐Arrow‐Two‐Hawks Strategy Achieves High Efficiency and Stable Batch Variance for Benzodifuran‐based Polymer Solar Cells

AbstractWith the development of organic solar cells (OSCs), the high‐performance and stable batch variance are becoming a new challenge for designing polymer donors. To obtain high photovoltaic performance, adopting polymers with high molecular weight as donors is an ordinary strategy. However, the high molecular weight need to subtly control the reaction time and state, inevitably caused batch‐to‐batch variations. Herein, a strategy of steric effect is applied to benzodifuran (BDF)‐based polymer by introducing different positions of Cl atom, producing two polymers PBDFCl‐1 and PBDFCl‐2. The more twisted side chains conformation not only achieve the control of moderate molecular weight for PBDFCl‐2, but also easily form molecular stacking through adopting BDF unit and maintain sufficient polymeric crystallinity. Due to the optimized stacking mode and good blend miscibility, PBDFCl‐2‐based device exhibitsa more elegant power conversion efficiency (PCE) of 17.00% compared to PBDFCl‐1‐based device. This is the highest efficiency record for BDF‐based binary OSCs. Meanwhile, the PCE device variation of the different molecular weights for PBDFCl‐2 is little, indicating the reduction of the batch variation. Therefore, smartly using steric effect of Cl atom in strong crystalline BDF unit can form efficient molecular stacking regulations and realize the coordination of high‐performance and stable batch variance.

Benzo[d]thiazole Based Wide Bandgap Donor Polymers Enable 19.54% Efficiency Organic Solar Cells Along with Desirable Batch-to-Batch Reproducibility and General Applicability.

The limited selection pool of high-performance wide bandgap (WBG) polymer donors is a bottleneck problem of the nonfullerene acceptor (NFA) based organic solar cells (OSCs) that impedes the further improvement of their photovoltaic performances. Herein, a series of new WBG polymers, namely PH-BTz, PS-BTz, PF-BTz, and PCl-BTz, are developed by using the bicyclic difluoro-benzo[d]thiazole (BTz) as the acceptor block and benzo[1,2-b:4,5-b']dithiophene (BDT) derivatives as the donor units. By introducing S, F, and Cl atoms to the alkylthienyl sidechains on BDT, the resulting polymers exhibit lowered energy levels and enhanced aggregation properties. The fluorinated PBTz-F not only exhibits a low-lying HOMO level, but also has stronger face-on packing order and results in more uniform fibril-like interpenetrating networks in the related PF-BTz:L8-BO blend. A high-power conversion efficiency (PCE) of 18.57% is achieved. Moreover, PBTz-F also exhibits a good batch-to-batch reproducibility and general applicability. In addition, ternary blend OSCs based on the host PBTz-F:L8-BO blend and PM6 guest donor exhibits a further enhanced PCE of 19.54%, which is among the highest values of OSCs.

Bioaccumulation, Trophic Transfer, and Biotransformation of Polychlorinated Diphenyl Ethers in a Simulated Aquatic Food Chain.

Polychlorinated diphenyl ethers (PCDEs) are detected in aquatic environments and demonstrate adverse effects in aquatic organisms. However, data regarding the environmental behavior of PCDEs in aquatic ecosystems are lacking. In the present study, a simulated aquatic food chain (Scenedesmus obliquus-Daphnia magna-Danio rerio) was constructed in a lab setting, and the bioaccumulation, trophic transfer, and biotransformation of 12 PCDE congeners were quantitatively investigated for the first time. The log-transformed bioaccumulation factors (BCFs) of PCDEs in S. obliquus, D. magna, and D. rerio were in the range of 2.94-3.77, 3.29-4.03, and 2.42-2.89 L/kg w.w., respectively, indicating the species-specific bioaccumulation of PCDE congeners. The BCF values increased significantly with the increasing number of substituted Cl atoms, with the exception of CDE 209. The number of Cl atoms at the para and meta positions were found to be the major positive contributing factors for BCFs in the case of the same number of substituted Cl. The lipid-normalized biomagnification factors (BMFs) of S. obliquus to D. magna, D. magna to D. rerio, and the whole food chain for the 12 PCDE congeners ranged at 1.08-2.27, 0.81-1.64, and 0.88-3.64, respectively, suggesting that some congeners had BMFs comparable to PBDEs and PCBs. Dechlorination was the only metabolic pathway observed for S. obliquus and D. magna. For D. rerio, dechlorination, methoxylation, and hydroxylation metabolic pathways were observed. 1H nuclear magnetic resonance (NMR) experiments and theoretical calculations confirmed that methoxylation and hydroxylation occurred at the ortho position of the benzene rings. In addition, reliable quantitative structure-property relationship (QSPR) models were constructed to qualitatively describe the relationships between molecular structure descriptors and BCFs for PCDEs. These findings provide insights into the movement and transformation of PCDEs in aquatic ecosystems.

Thermochemistry and Kinetics of the OH- and Cl-Initiated Degradation Pathways of the HCFC-132b Atmospheric Pollutant

The gas-phase hydrogen abstraction reaction of 1,2-dichloro-1,1-difluoroethane (CH2ClCClF2) with OH and Cl radicals is theoretically investigated by employing density functional theory methods combined with coupled-cluster-based composite schemes. The mechanism and kinetics of the degradation entrance channels of CH2ClCClF2, recently detected with increasing concentration in the atmosphere, is elucidated by using cost-effective ab initio triple-slash dual-level direct dynamics, jChS//B2PLYP-D3(BJ)/jun-cc-pV(T+d)Z///M06-2X-D3/jun-cc-pV(T+d)Z. Thermal rate constants are calculated over the temperature range of 200–1000 K by adopting both canonical- (CVT) and microcanonical (μVT)-variational transition state theory also including the microcanonically optimized multidimensional tunneling transmission coefficient (μOMT). The theoretical rate coefficient for the H-abstraction reaction initiated by the OH radical is computed to be kOHCVT/μOMT = 1.72 × 10–14 cm3 molecule–1 s–1 and kOHμVT/μOMT = 1.57 × 10–14 cm3 molecule–1 s–1 at 298 K, in excellent agreement with the available experimental data. The rate constant for the H-abstraction reaction by the Cl atom, here obtained for the first time, is predicted to be kClCVT/μOMT = 5.96 × 10–14 cm3 molecule–1 s–1 and kClμVT/μOMT = 5.65 × 10–14 cm3 molecule–1 s–1 at 298.15 K, thus showing increased efficiency with respect to the OH-prompted reaction.

Boosting electrocatalytic CO2 reduction over Ni/CN catalysts derived from metal-triazolate-framework by doping with chlorine

The CO2 electrochemistry reduction (CO2ER) to valuable chemicals is one of the attractive strategies for the utilization of greenhouse gas and carbon recovery. The catalyst for the reaction is extremely important. In the present work, a carbon matrix derived from the pyrolysis of nitrogen-rich metal triazole (MET) supported Ni-metal (denoted as Ni/CN) was developed as a catalyst for the CO2ER. A catalyst with a heteroatom chlorine introduction, named the Ni/(Cl-CN), enhanced the catalytic performances remarkably. The Ni/(Cl-CN) catalyst with the Ni loading of 4.5 wt% showed the best catalytic performance with a Faradaic efficiency of CO (FECO) over 90% in a range of −0.7 to −1.1 V (vs. RHE) in 0.1 M KCl solution, and the highest formation activity reached 137.1 mmol∙gcat−1·h−1. Besides, the highest total current density reached 21.4 mA cm−2 (FECO>90%) in an H-type cell at −1.1 V (vs. RHE). The catalyst was characterized by diverse technologies, and the results indicated that it contains Ni NPs and homogenous dispersed Ni sites, and both of them are active for the reaction. The introduction of Cl atom indeed promotes the catalytic performance probably via the stabilization of Ni+ species and enhances the CO2 adsorption and activation. The present work not only provides an efficient heteroatom-doped metal-NC catalyst in CO2ER to CO but also sheds light on tuning catalytic performances by doping halogen atoms.

Cooperative Ternary Assemblies Involving Anion–π/π–π/Anion–π Assemblies and Unconventional Cl⋯Cl Interactions in Cu(II) Coordination Compounds: Experimental and Theoretical Studies

Two coordination compounds of Cu(II), namely, [Cu (phen)2Cl](NO3)·H2O (compound 1) and [Cu2(µ-Cl2)Cl2(Hdmpz)4] (compound 2), where phen = 1,10-phenanthroline and Hdmpz = 3,5-dimethylpyrazole, were synthesized at room temperature and characterized using elemental analysis, TGA, spectroscopic techniques (FT-IR and electronic) and single-crystal X-ray diffraction studies. The cooperative anion–π/π–π/anion–π assemblies involving the coordinated phen, along with the uncoordinated nitrate moieties, played pivotal roles in the stabilization of the crystal structure of compound 1. Unconventional type I Cl⋯Cl interactions involving the coordinated Cl atoms provided reinforcement to the crystal structure of compound 2. We theoretically explored the supramolecular assemblies observed in the crystal structures of compounds 1 and 2 using DFT calculations, MEP surface analysis and combined NCI plot/QTAIM computational tools. Theoretical analysis revealed that the antiparallel π-stacking interactions in compound 1 and the N–H···Cl H-bonds in compound 2 were the strong structure-guiding non-covalent synthons which stabilized the compounds. In the anion–π/π–π/anion–π assembly observed in compound 1, the anion–π interaction reinforced the π-stacking by reducing the electrostatic repulsion between the metal-coordinated electron-deficient phen rings.

Ziegler Natta catalyst by precipitation of soluble precursor in different synthesis conditions

Catalysts for the polymerization of ethylene were created through the use of a solution based catalyst precursor that incorporated magnesium ethoxide-titanium tetra butoxide. A novel chlorinating agent, ethyl aluminum sesquichloride (EASC), was utilized for the precipitation of the catalyst. The resulting catalysts were then evaluated through a range of analytical techniques, including FTIR, FE-SEM, BET, particle size analysis, and elemental analysis. The chlorination reaction temperatures and EASC/Mg molar ration were changed, and the final catalysts were investigated and polymerized (ZMC 1–3). The formation of the Mg-Cl bond was detected in all catalysts by FTIR. FE-SEM images of the catalysts revealed rectangular crystalline structures surrounded by an amorphous sub-grain material. All of the catalysts have a similar concentration of titanium, with only a minor portion of the titanium being removed due to decanting, Most of the primary titanium is placed on the catalyst support independent of the change in the synthesis procedure. The results showed that chlorination at a higher temperature (110 °C) made the catalyst with smaller particle size, narrower PSD, higher surface area, and higher activity. The findings indicated that increasing the temperature of chlorination at 110 °C resulted in the production of catalysts with smaller particle size, more narrow particle size distribution, increased surface area, and improved activity. Reducing the amount of EASC by half at 110 °C provides an adequate amount of Cl atoms for catalyst preparation and reduces the amount of required washing solution. In the following, the effect of tetraethyl orthosilicate (TEOS) as an alkoxy electron donor before and after precipitation was examined and named ZMC 4 and ZMC 5 respectively. Then catalyst was investigated in homo and copolymerization of ethylene/1-butene. As a result, the catalyst activity decreased in the presence of an electron donor, and the kinetic algorithm changed from decay to the buildup type. The activity drop was less in ZMC 5, the density and DSC analysis showed that the comonomer distribution was better in ZMC 4.