CH2Cl2 Solvent Research Articles

Structural designs and synthesis of co-polycarbonates with cyclohexyl and fluorene structures: Low-dielectric constant, high solubility, and superior mechanical properties

The rapid developments of high-speed communication and large-scale integrated circuits have accelerated the research for insulating dielectric materials with low dielectric constant, low dielectric loss, and good mechanical properties. In this study, a series of polycarbonate resins containing cyclohexyl and fluorene structures are synthesized by melt transesterification, which is low dielectric, highly thermally resistant, and soluble. The effects of fluorene structure contents on the properties of a co-polycarbonate resin were studied systematically. The results showed that the non-polar fluorene group could reduce the molecular polarization of co-polycarbonate, resulting in low permittivity of co-polycarbonate are 2.41-2.71@1MHz. In addition, the resin has excellent solubility and can be dissolved in NMP, CH2Cl2, THF, and other solvents at room temperature. Furthermore, the co-polycarbonate resins also exhibit superior heat resistance with glass transition temperature (Tg) of 160.6-173.1 °C as well as admirable mechanical properties with a tensile strength of 50.54-70.72 MPa. This makes it a promising candidate for high-speed communications and large-scale integrated circuits.

Information-theoretic quantities as effective descriptors of electrophilicity and nucleophilicity in density functional theory.

Electrophilicity and nucleophilicity are two vastly important chemical concepts gauging the capability of atoms in molecules to accept and donate the maximal number of electrons. In our earlier studies, we proposed to simultaneously quantify them using the Kullback-Leibler divergence from the information-theoretic approach in density functional theory. However, several issues with this scheme remain to be clarified such as its general validity, predictability, and relationship with other information-theoretic quantities. In this work, we revisit the matter with bigger datasets and deeper theoretical insights. Five information-theoretic quantities including Kullback-Leibler divergence, Hirshfeld charge, Ghost-Berkowitz-Parr entropy, and second and third orders of relative Onicescu information energy are found to be reliable and robust descriptors of electrophilicity and nucleophilicity propensities. Employing these five descriptors, we design a list of new compounds and predict their electrophilicity and nucleophilicity scales. This work should markedly improve our confidence and capability in applying information-theoretic quantities to evaluate electrophilicity and nucleophilicity propensities and henceforth pave the route for more applications of these quantities from information-theoretic approach in density functional theory in the future. All structures were fully optimized at the M06-2X/6-311 + G(d) level of DFT functional using the Gaussian 16 package (version C01) with integration grids and tight self-consistent-field convergence. The solvent effect was taken into account by using the implicit solvent model (CPCM) in the CH2Cl2 solvent, and all 3D contour surfaces of Fukui function, local temperature, and ITA (information-theoretic approach) quantities were generated by GaussView. The Multiwfn 3.8 program was used to calculate the ITA indexes and atomic charges.

Red/near-infrared (NIR) difluoroboron β-diketonate derivatives with reversible mechanochromism for cellular imaging

Near-infrared (NIR) fluorophores have promoted the development of materials for bioimaging, but traditional NIR dyes usually suffer from aggregation-caused quenching (ACQ), impeding their applications. Herein, we propose two difluoroboron β-diketonate complexes TBO and TBS, consisting a donor–acceptor (D-A) structure with triphenylamine (TPA) moiety as an electron donors and difluoroboron as well as furan or thiophene building block as an electron acceptor. The theoretical calculation and optical data shows that both of them have intramolecular charge transfer (ICT) characteristics. Such ICT characteristics endow them with both solvatochromism and dual-state emission (DSE) properties. In the solvent CH2Cl2, the emission wavelength of TBO ranges from 550 nm to 750 nm, with a low fluorescence quantum yield (Φ = 7.0 %). However, in the less polar solvent hexane, the emission wavelength blue-shifts, with an increased Φ reaching up to 18 %. Moreover, TBO and TBS exhibit mechanochromic characteristics and rare multi-channel fluorescence emission phenomena at solid-state. Their solid-state samples can emit fluorescence in four spectral bands with maximum emission wavelengths at 300 nm, 400 nm, 600 nm, and 770 nm under excitation at 240 nm. These unique optical properties are expected to be utilized for detecting polarity of system and deformation. Moreover, according to the results of cell imaging and flow cytometry, TBO molecular were easily internalized into Hela cells and distributed in the cytoplasm with strong red fluorescence. Therefore, this research inspires more insight into development of NIR luminogens for biomedical imaging.

Vaporchromic Domino Transformation and Polarized Photonic Heterojunctions of Organoplatinum Microrods.

Photonic heterostructures with codable properties have shown great values as versatile information carriers at the micro and nanoscale. These heterostructures are typically prepared by a step-by-step growth or post-functionalization method to achieve varied emission colors among different building blocks. In order to realize high-throughput and multivariate information loading, we report here a strategy to integrate polarization signals into photonic heterojunctions. A U-shaped di-Pt(II) complex is assembled into highly-polarized yellow-phosphorescent crystalline microrods (Y-rod) by strong intermolecular Pt···Pt interaction. Upon end-initiated desorption of the incorporated CH2Cl2 solvents, Y-rod is transformed in a domino fashion into tri-block polarized photonic heterojunctions (PPHs) with alternate red-yellow-red emissions or red-phosphorescent microrods (R-rod). The red emissions of these structures are also highly polarized; however, their polarization directions are just orthogonal to those of the yellow phosphorescence of Y-rod. With the aid of a patterned mask, R-rod is further programmed into multi-block PPHs with precisely-controlled block sizes by side-allowed adsorption of CH2Cl2 vapor. X-ray diffraction analysis and theoretical calculations suggest that the solvent-regulated modulation of intramolecular and intermolecular excited states is critical for the construction of these PPHs.

Design of a new home-made ultrasonic extraction system

Innovative, sensitive, and accurate method for liquid-liquid extraction using an ultrasonic device is presented in this work. A working system was created, consisting of two basic components: the ultrasonic device and the pump device, to pump or withdraw the organic layer. a study of the key variables derived from the liquid-liquid system was carried out in the system containing Dithizone (1×10^ ̄ 3 M) in (Chloroform) CHCl₃ solvent. and aqueous copper (II) chloride(CuCl2.2H2O) (1×10^ ̄6 M) solution to determine the degree to which they affect the extraction performance attained in this manner. The effect of initial sample copper concentration and ultrasonic time, temperature effect, and pump speed, were studied, establishing the best conditions for a sample of (10 mL) aqueous solution of Cu (II) chloride, the optimum copper (II) concentration in the analyzed sample is (1×10^ ̄ 6 M), the ultrasonic time for the device is (8 min), and the flow rate of the pump is (3mL/30sec) and a temperature (27ºC) and (pH=1). The extraction degree was optimum under these conditions (96±2%) and the relative standard deviation (RSD)% (0.29%), In this work, a simple method is proposed to extract and concentrate copper in aqueous copper chloride using an ultrasonic device in the presence of dithizone solvent. The main parameters affecting the extraction method such as copper ion concentration, pump speed, temperature, device time, and the effect of equal and different volumes were evaluated. The proposed method was applied for the determination of copper in aqueous copper chloride samples. Accuracy was assessed by comparing the results with a conventional extraction method (traditional methods).

Unexpected Intermolecular C-H···O Hydrogen Bonds and 1H NMR Chemical Shifts in a Key Linker for Fluorine-18 Labeling of Dimeric Drugs.

The compound 2-{[(trifluoromethyl)sulfonyl]oxy}propane-1,3-diyl bis(4-methylbenzenesulfonate) (TPB) is a crucial intermediate in the synthesis of 18F-radiolabeled cromolyn derivatives. In this work, we combine 1H NMR spectroscopy, X-ray crystallography, ab initio molecular dynamics, and NMR calculations to examine the structure, interactions, and solvation dynamics of the TPB molecule. In CDCl3, the CH2 groups within its glyceryl-derived linker exhibit a single set of proton signals in the 1H NMR measurements. However, when TPB is dissolved in DMSO-d6, distinct splitting patterns emerge despite its seemingly symmetric chemical structure. Crystallographic analysis further unveils the absence of overall symmetry in its three-dimensional arrangement. To elucidate these unique NMR features, we carry out ab initio molecular dynamics simulations and characterize the solvation structures and dynamics of TPB in CHCl3 and DMSO solutions. In contrast to the predominantly nonpolar nature of the CHCl3 solvents, DMSO directly participates in C-H···O hydrogen-bonding interactions with the solute molecule, leading to the splitting of its -CH2 chemical shifts into two distinct distributions. The comprehensive understanding of the structure and solvation interactions of TPB provides essential insights into its application in the radiofluorination reactions of cromolyn derivatives and holds promise for the future development of radiolabeled dimeric drugs.

Synthesis and crystal structures of 5,17-dibromo-26,28-dihydroxy-25,27-dipropynyloxycalix[4]arene, 5,17-dibromo-26,28-dipropoxy-25,27-dipropynyloxycalix[4]arene and 25,27-bis(2-azidoethoxy)-5,17-dibromo-26,28-dihydroxycalix[4]arene

The calixarenes, 5,17-dibromo-26,28-dihydroxy-25,27-dipropynyloxycalix[4]arene (C34H26Br2O4, 1), 5,17-dibromo-26,28-dipropoxy-25,27-dipropynyloxycalix[4]arene (C40H38Br2O4, 2) and 25,27-bis(2-azidoethoxy)-5,17-dibromo-26,28-dihydroxycalix[4]arene (C32H28Br2N6O4, 3) possess a pinched cone molecular shape for 1 and 3, and a 1,3-alternate shape for compound 2. In calixarenes 1 and 3, the cone conformations are additionally stabilized by intramolecular O—H...O hydrogen bonds, while in calixarene 2 intramolecular Br...Br interactions consolidate the 1,3-alternate molecular conformation. The dense crystal packing of the cone dialkyne 1 is a consequence of π–π, C—H...π and C—H...O interactions. In the crystal of the diazide 3, there are large channels extending parallel to the c axis, which are filled by highly disordered CH2Cl2 solvent molecules. Their contribution to the intensity data was removed by the SQUEEZE procedure that showed an accessible void volume of 585 Å3 where there is room for 4.5 CH2Cl2 solvent molecules per unit cell. Rigid molecules of the 1,3-alternate calixarene 2 form a columnar head-to-tail packing parallel to [010] via van der Waals interactions, and the resulting columns are held together by weak C—H...π contacts.

Metabolomics-based analysis of the diatom Cheatoceros tenuissimus combining NMR and GC–MS techniques

Metabolomics, a recent addition to omics sciences, studies small molecules across plants, animals, humans, and marine organisms. Nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC–MS) are widely used in those studies, including microalgae metabolomics. NMR is non-destructive and highly reproducible but has limited sensitivity, which could be supplemented by joining GC–MS analysis. Extracting metabolites from macromolecules requires optimization for trustworthy results. Different extraction methods yield distinct profiles, emphasizing the need for optimization. The results indicated that the optimized extraction procedure successfully identified NMR and GC–MS-based metabolites in MeOH, CHCl3, and H2O extraction solvents. The findings represented the spectral information related to carbohydrates, organic molecules, and amino acids from the water-soluble metabolites fraction and a series of fatty acid chains, lipids, and sterols from the lipid fraction. Our study underscores the benefit of combining NMR and GC–MS techniques to comprehensively understand microalgae metabolomes, including high and low metabolite concentrations and abundances.•In this study, we focused on optimizing the extraction procedure and combining NMR and GC–MS techniques to overcome the low NMR sensitivity and the different detected range limits of NMR and GC–MS.•We explored metabolome diversity in a tropical strain of the small cells’ diatom Cheatoceros tenuissimus.

Identification of potential DPP-4 inhibitors from Bryophyllum pinnatum by in-silico analysis

Background: An estimated 463 million people already live with diabetes and that figure is set to rise to over 700 million by 2045, as per the International Diabetes Federation (IDF). The current form of treatment for Type-2 DM can be done with sulfonylureas, meglitinides, metformin, thiazolidinediones, incretin mimetics: Glucagon-like peptide 1 (GLP-1), Glucose-dependent insulinotropic polypeptide (GIP), and amylin analogues (Pramlintide). Bryophyllum pinnatum (Lam.) Oken (B. pinnatum) belongs to the plant family crassulaceae used in traditional medicine in Asia. GLP-1 and Glucose-dependant Insulinotropic Polypeptide (GIP), both play a similar role in stimulating insulin secretion and are inactivated by dipeptidyl peptidase-4 (serine protease dipeptidyl peptidase-4) enzymes. Aims: To identify the potential anti-diabetic active compounds of Bryophyllum pinnatum against DPP-4 enzyme using in-silico methods. Methods and Material: The phytochemicals associated with Bryophyllum pinnatum were retrieved from ChEBI and canonical SMILES retrieved, followed by searching for its molecular properties and druglikeness using MolSoft LLC, toxicity test using ADVERPred, Swiss Target Prediction for predicting the DPP-4 inhibitors, molecular docking using Schrodinger software suite. Results: The in-silico study identified two phytochemicals from fourteen that have been predicted for DPP-4 inhibition potential against Type-2 DM. In CH2CL2 and CH3OH solvent compounds 3,5-dihydroxybenzoic acid (-5.623 kcal/mol) and 3,4-didehydro-N4-deethylbrinzolamide (-4.91 kcal/mol) displayed the highest docking scores against human DPP-4 (5Y7K). Conclusions: The above-mentioned compounds revealed no side effects. The in-silico results strongly favour the beneficial use of phytochemicals from Bryophyllum pinnatum as a probable herb that can be used for adjuvant therapy. Further in-vitro and in-vivo tests are needed for confirmation.

Star-shaped small donor molecules based on benzotriindole for efficient organic solar cells: a DFT study.

The purpose of the S01-S05 series of end-capped modified donor chromophores is to amplify the energy conversion efficiency of organic solar cells. Using quantum chemical modeling, the photophysical and photoelectric characteristics of the S01-S05 geometries are examined. The influence of side chain replacement on multiple parameters, including the density of states (DOS), molecular orbital analysis (FMOS), exciton-binding energy (Eb), molecular electrostatic potential analysis, dipole moment (μ), and photovoltaic characteristics including open circuit voltage (VOC), and PCE at minimal energy state geometries, has been investigated employing density functional theory along with TD-DFT analysis. The molar absorption coefficient (λmax) of all the proposed compounds (S01-S05) was efficiently enhanced by the terminal acceptor alteration technique, as demonstrated by their scaling up with the reference molecule (SR). Among all molecules, S04 has shown better absorption properties with a red shift in absorption having λmax at 845nm in CHCl3 solvent and narrow energy gap (EG) 1.83eV with least excitation energy (Ex) of 1.4657eV. All created donors exhibited improved FF and VOC than the SR, which significantly raised PCE and revealed their great efficiency as OSC. Consequently, the results recommended these star-shaped molecules as easily attainable candidates for constructing extremely efficient OSCs.

Synthesis, Physicochemical and Third Order Nonlinear Optical Properties of Bis-Chalcone (BBDP) as Donor-pi Acceptor Chromophore in Organize Medium.

Bis-Chalcone (BBDP) has been prepared by condensation of N, N-dimethyl benzaldehyde and 1,1'-([1,1'-biphenyl]-4,4'-diyl) di (ethan-1-one), and structure of BBDP was characterized by Mass Spectra, 13C-NMR, 1H-NMR, and IR. Physicochemical properties including Dipole-moments, Stoke-Shifts, Oscillator-strength, dielectric constant and quantum-yields of fluorescence of BBDP were investigated by the emission and absorbances in different solvents. Compound (BBDP) displayed bathochromic shift upon increasing the solvent polarity (from n-Hexane to DMSO). Furthermore, we have exploited third-order nonlinear optical characteristics of the bisChalone were invigilated by the Z-scan techniques in Chloroform. The measurements were taken with a continuous-wave (CW) diode laser having a wavelength of 520 nm in CHCl3 solvent. The third-order nonlinear optical properties, such as the nonlinear refractive index (NLRI) n2, nonlinear absorption coefficient (NLAC) β, and nonlinear susceptibility χ(3), were measured at various solution concentrations and laser powers. The obtained values of n2, β, and χ(3) were estimated to be high, of the order of 10-7(cm2/W), 10-3 (cm/W), and 10-6 (esu), respectively. As a result, bis-chalcone (BBDP) is considered as a promising candidate for applications in nonlinear optical (NLO) devices and optical limiting (OL).

Ordered nanoassemblies from self‐assembly of amphiphilic molecule containing pillar[5]arene and azobenzene groups

AbstractThe derivatization of pillar[n]arenes is a prerequisite for endowing them with functions, as well as enriching the application of pillar[n]arene materials in advanced material science. Herein, we report the self‐assembly of amphiphilic rim‐differentiated pillar[5]arene (H1). One side of the pillar[5]arene is composed of hydrophilic poly(ethylene oxide) chains, benzene and azobenzene groups connected with ether bonds, and the other side is composed of ethoxy groups. In CHCl3 solvent, the amphiphile H1 self‐assembled into spherical micelles, while in H2O/THF mixed solvent H1 self‐assembled into nanorod‐like assemblies. Interestingly, addition of a guest molecule composed of tetraphenylethene and hexanenitrile groups (G1) to the CHCl3 solution of H1 produces large sheet aggregates via the strong π–π stacking of rod segments. The reversible transformation between the nanosheet assemblies of host–guest complexes and nanoparticles is achieved by addition of the guest molecule 1,4‐butylamine (G2) and pillar[5]arene with ethoxy groups as competitive molecules. Notably, worm‐like and nanorod micelles of H1 were constructed in H2O/THF solution triggered by light irradiation, which assemblies can be used as photosensitive erasable writing materials. © 2023 Society of Industrial Chemistry.

Phenyl versus triazinyl π-Linkers in phenohydrazine, phenoxazine and phenothiazine-based dye-sensitized solar cells: A computational investigation

The present study focuses on designing six new organic dyes derived from phenohydrazine, phenoxazine and phenothiazine, with modifications to the π-linker groups. Different characteristics, including structural, electronic, frontier molecular orbital, chemical reactivity, transition density matrix, molecule electrostatic potential, and driving force parameters, were examined using density functional theory (DFT) at the B3LYP/6–31 G (d,p) level. Additionally, the optical characteristics of the dyes in the CH2Cl2 solvent were evaluated using the time-dependent DFT (TD-DFT) with the TD-BH and H/6–31 G (d,p) method. Geometrical factors, optoelectronic qualities, frontier molecular orbitals, electrostatic surface potential, absorption spectra, and electron-accepting and -donating properties were all included in this thorough investigation. The examined dyes exhibited noteworthy properties, including λmax values ranging from 362.1 to 471.8 nm, band gaps within the range of 1.60–2.34 eV, a high LHE of approximately 0.994 for five dyes, indicating a robust electron-donating capacity, as well as a significant intramolecular charge transfer property. Notably, dyes featuring triazinyl outperformed those with phenyl among the designed compounds.

Panchromatic and Perturbed Absorption Spectral Features and Multiredox Properties of Dicyanovinyl- and Dicyanobutadienyl-Appended Cobalt Corroles.

Four new β-functionalized π-extended cobalt corroles with one and two dicyanovinyl (DCV) or dicyanobutadienyl (DCBD) moieties at the 3- and 3,17-positions have been synthesized and characterized by various spectroscopic techniques. Interestingly, the synthesized DCV- and DCBD-appended cobalt corroles displayed panchromatic and near-infrared absorption in the range 300-1100 nm in CH2Cl2 and pyridine solvents. (MN)2-(Cor)Co and A2MN2-(Cor)Co exhibited 8-9 times enhancement in the molar absorptivity of the Q band compared to the parent corrole ((Cor)Co). The unique absorption spectral features of these β-functionalized cobalt corroles are splitting, broadening, and red-shifting in the Soret and Q bands. One DCV unit brings a 30-46 nm red shift, whereas one DCBD unit brings a 40-75 nm red shift in the Q band compared to the corresponding precursors. This is rare that the intensity of the longest Q band is greater than or equal to the Soret-like bands. These corrole derivatives exhibit UV-vis spectral features similar to those of chlorophyll a. A 220 mV positive shift per DCV group and 160 mV positive shift per DCBD group were observed in the first oxidation potentials compared to (Cor)Co in the desired direction for the utility of these cobalt complexes in electrocatalysis. DFT studies revealed that HOMO and LUMO were stabilized after appending DCV and DCBD groups on the corrole macrocycle and exhibited a "push-pull" behavior leading to promising material applications in nonlinear optics (NLO) and catalysis.

Method Comparison for the Identification and Characterization of Odorants from Scots Pine (Pinus sylvestris L.) and Oriented Strand Boards (OSB) Made Thereof by GC-MS and GC-FID/O Using Different Headspace Techniques

Volatile organic compounds (VOCs) from wood and wood composites are important contributors to odor profiles of indoor environments and can significantly influence human health and well-being. GC-MS/FID and gas chromatography (GC) with olfactometric detection (GC-O) are employed for the identification and characterization of odorants. Four different sample preparation methods are evaluated on wood strands and isocyanate adhesive–based oriented strand boards (OSBs) made from Pinus sylvestris L.: among these, dynamic headspace extraction thermal desorption ((dynamic) HS-TD), head space solid phase microextraction (HS-SPME), head space solid phase microextraction Arrow (HS-SPME Arrow), and liquid injection of a CH2Cl2 solvent extract. The olfactometric investigation revealed over 30 odor-active substances of cyclic and acyclic monoterpene, monoterpenoid ketone, monoterpenoid aldehyde, monoterpenoid alcohol, monoterpenoid ester, aliphatic aldehyde, alcohol, and acid and phenolic chemistry. Compared to liquid injection, (dynamic) HS-TD was found to result in a similar number of odorants (20 vs. 24), whereas HS SPME Arrow shows good performance with minimal instrumental effort, notably for monoterpene and aldehyde compounds. Native wood vs. OSB showed high concentrations of saturated and unsaturated aldehydes for the wood board sample. These findings demonstrate the capability of headspace methods for odorant detection and their suitability for standardization towards a database for wood and wood composites.

Crystal Structures of DNA Intercalating Agents Dipyrido[3,2-f:2′,3′-h]quinoxaline (dpq), (Benzo[i]dipyrido[3,2-a:2′,3′c]phenazine (dppn), and [Ir(ppy)2(dppn)][PF6] (Where Hppy = 2-Phenylpyridine)

Pyrazino-phenanthroline ligands are commonly used with transition metals as DNA intercalation agents. Herein, we report the characterization of two commonly utilized pyrazino-phenanthroline ligands, dipyrido[3,2-f:2′,3′-h]quinoxaline (dpq) and (benzo[i]dipyrido[3,2-a:2′,3′c]phenazine (dppn), by single-crystal X-ray diffraction. Additionally, the characterization of [Ir(ppy)2(dppn)][PF6], where Hppy = 2-phenylpyridine, by single-crystal X-ray diffraction is described. Both the dpq and dppn ligands crystallize as chloroform solvates where the chloroform molecule occupies the equivalent binding pocket of a metal in metal complexes of these ligands. These pyrazino-phenanthrolines are largely planar, with the dppn ligand displaying a slight twist. When the dppn ligand is coordinated to iridium(III), the dppn ligand on the resulting complex displays a significant degree of bending along the longitudinal direction of the ligand. This iridium (III) complex crystallizes as a CH2Cl2 and Et2O solvate and due to the volatility of these solvents these crystals are only stable for a few seconds outside of the mother liquor. The structures of the free ligands and the [Ir(ppy)2(dppn)][PF6] complex all display extensive π stacking interactions.

Crystal structure and Hirshfeld surface analysis of 3-(bromo-meth-yl)-2-[1,2-di-bromo-2-(6-nitro-benzo[d][1,3]dioxol-5-yl)eth-yl]-1-(phenyl-sulfon-yl)-1H-indole chloro-form 0.585-solvate.

The title indole derivative, C24H17Br3N2O6S, crystallizes with a partial occupancy [0.585 (4)] CHCl3 solvent mol-ecule. The dihedral angles between the indole ring system and pendant nitro-benzodioxolane rings system and phenyl-sulfonyl ring are 4.81 (14) and 72.24 (19)°, respectively. In the crystal, the indole mol-ecules are linked to each other and to the chloro-form mol-ecule by weak C-H⋯O, C-H⋯Cl, C-H⋯π, C-Br⋯π and C-Cl⋯π and aromatic π-π stacking inter-actions. A Hirshfeld surface analysis was carried out and the inter-molecular contacts with the most significant contributions are H⋯O/O⋯H (24.3%), H⋯H (18.4%), Br⋯H/H⋯Br (16.8%) and C⋯H/H⋯C (8.4%).

The slow magnetic relaxation in Dy-phthalocyanine single-molecule magnet induced by CH2Cl2 solvent molecules

DyPc2 and DyPc2•CH2Cl2 were prepared using the solvent thermal method. The x-ray diffractometer and the Fourier transform infrared spectrometer were used to explore the structure changes between DyPc2 and DyPc2•CH2Cl2. The results clearly demonstrate that the CH2Cl2 molecule can alter the crystal structures and, thus, change the molecular stacking structures of DyPc2 without destroying molecular integrity. Geometry optimization further proved that DyPc2 belongs to the space group P212121, while DyPc2•CH2Cl2 crystallizes in the space group Pnma. It is clearly demonstrated that the different molecular environment affects the structure of a single DyPc2 molecule to some extent, such as the twist angles of two Pc rings and the Pc−Dy−Pc angles. The molar magnetic susceptibility and hysteresis loops for DyPc2 and DyPc2•CH2Cl2 were also measured and compared. The negative Weiss constants were obtained by the Curie−Weiss law fitting above 50 K. The hysteresis loop for DyPc2•CH2Cl2 is wider than that of DyPc2, implying that the magnetic relaxation of DyPc2 slowed down, while quantum tunneling of the magnetization is prevented efficiently after absorbing CH2Cl2 molecules. This work clarifies the correlation between the molecular environment and magnetism of single-molecule magnets, which is helpful for their design guideline and future applications.

Secondary Metabolites from Terminalia Catappa and Evaluation of its Bioactivities

Bangladesh is a land of medicinal plants. Terminalia catappa is an important medicinal plant of Bangladesh which is used for various pharmacological and biological activities like hepatoprotective, antioxidant, anti-fertility, antidiabetic, anticoagulant and antimicrobial. The coarsely powder dried stem bark sample of T. catappa was extracted by the solvent CHCl3. The concentrated extract was then fractionated by flash column chromatography using petroleum ether, ethyl acetate and methanol as solvents respectively. The column fraction was further fractionated with void liquid chromatography. Repeated preparative thin layer chromatography of selective fractions resulted in the isolation of two compounds which were identified as a triterpenoid, taraxerol (1) and a steroid, Stigmastane-3, 6-diol (2). The structure of these compounds were elucidated by 1H NMR spectroscopy and by comparison with reported values. This is the first report of the isolation of these compounds from this plant. The different extracts also showed significant antibacterial activity against gram positive and gram negative bacteria. The methanol extract did not show significant activity. The antifungal activity of different extract of T. catappa demonstrated promising zone of inhibition except Saccharomyces cerevecae. In the brine shrimp lethality bioassay, the extract of T. catappa exhibited a significant cytotoxic activity. The LC50 value of CHCl3 soluble extract was found to be 1.55 μg/ml. T. catappa was also reported to have free radical scavenging activity with IC50 value of 255.0 μg/ml. Since this plant demonstrated a number of promising pharmacological biological activities, so it can be a good source of natural medicine. Bioresearch Commu. 9(2): 1310-1319, 2023 (July)

Newly designed triazatruxene-based dye-sensitized solar cells containing different benzothiazine π-linkers: Geometric, optoelectronic, charge transfer properties, and cyanoacrylic acid versus benzoic acid

In this work, six new organic (D–π–A) dyes based on triazatruxene have been designed by modifying the π- linkers groups and the anchor unit of the reference dye R. Their structural, electronic, frontier molecular orbital, chemical reactivity, and photovoltaic have been studied using DFT (density functional theory) at B3LYP/6-31G (d,p). Furthermore, the TD-DFT (time-dependent DFT) at TD-BHandH/6-31G (d,p) level method was chosen to calculate the optical characteristics of the investigated dyes in the solvent CH2Cl2. Molecular properties such as geometric parameters, optoelectronic properties, frontier molecular orbitals, natural bonding orbitals, the partial density of states analysis, electrostatic surface potential, absorption spectra, and electron accepting and donating parameters were assessed to predict proper candidates for the DSSC device. The studied dyes not only show significant λmax in the range of 500–650 nm, with a band gap in the range of 1.64–1.98 eV, lower λtot, but also high light capture efficiency and significant intramolecular charge transfer properties compared to the reference dye (R). Notably, dyes with C(CH3)2 and Si(CH3)2 exhibit the best performance among the designed dyes.