Single Crystal XRD Studies Research Articles

Magnetic, Optical, and Thermic Properties of SrLnCuSe3 (Ln = Dy, Ho, Er, Tm) Compounds

SrLnCuSe3 (Ln = Dy, Ho, Er, Tm) compounds crystallize in the Pnma and Cmcm orthorhombic space group and belong to the Eu2CuS3 and KCuZrS3 structural type, respectively. According to a single-crystal XRD study, the SrTmCuSe3 unit cell parameters are a = 4.0631 (4), b = 13.4544 (14), c = 10.4430 (10) Å, and V = 570.88 (10) Å3. All the studied SrLnCuSe3 samples in the temperature range of 1.77–300 K demonstrate paramagnetic behavior without any features pointing to magnetic ordering. The measured Curie constants coincide with the values expected for Ln3+ ions with good accuracy, which confirms the stoichiometric composition of the samples and the non-magnetic state of the copper ions, Cu1+ (S = 0). The conducted optical absorption study showed that the polycrystalline SrLnCuSe3 (Ln = Dy, Ho, Er, Tm) samples are semiconductors with a direct bandgap ranging from 2.14 eV to 2.31 eV. Two indirect bandgaps were revealed and explained by the presence of optical transitions to highly dispersive subbands in the conduction band. The compounds demonstrate two reversible phase transitions α⇆β, β⇆γ and an incongruent melting at 1606 K (Dy), 1584 K (Ho), 1634 K (Er), and 1620 K (Tm) associated with the formation of solid solutions of SrSe, Cu2-XSe, and Ln2Se3 binary compounds.

Synthesis of quinoline/oxindole appended phenylvinyl-2,5-dihydrofuran derivatives via ring-closing enyne metathesis

A sequential synthetic process was developed to synthesize quinoline/oxindole appended phenylvinyl-2,5-dihydrofuran derivatives. The synthesis involved multiple steps, starting with the base-promoted nucleophilic addition of terminal alkynes to specific carbonyl compounds (11H-indeno[1,2-b]quinolin-11-one and isatin derivatives). The resulting propargyl alcohol derivatives were then subjected to O-allylation. Subsequently, the 1,6-enyne compounds obtained underwent ring-closing enyne metathesis using Grubb's II catalyst, resulting in the desired quinoline/oxindole appended phenylvinyl-2,5-dihydrofuran derivatives. The structures and relative stereochemistry of the synthesized compounds were confirmed by spectroscopic analysis and single-crystal XRD studies.

Newer chalcone scaffolds with reactive functional groups: Process, spectral and single crystal XRD studies

Chalcones are versatile scaffolds for the synthesis of various heterocyclic systems with commercial utility. This work describes the synthesis of five novel chalcone derivatives. Syntheses were performed by a simple one-pot, straightforward Claisen-Schmidt condensation catalyzed with pyrrolidine and KOH. The chalcones were prepared by condensation of 4-formylbenzonitrile with different aromatic ketones at room temperature. The structures of all compounds have been investigated by FT-IR, NMR, and HR-MS spectroscopy. In addition, one chalcone structure was characterized by single-crystal XRD study. Crystal data for C21H15NO2 (Ch2): monoclinic, space group P21/c (no. 14), a = 6.5694(3) Å, b = 33.2697(15) Å, c = 7.4516(4) Å, β = 97.563(2)°, V = 1614.47(14) Å3, Z = 4, T = 293(2) K, μ(MoKα) = 0.083 mm-1, Dcalc = 1.289 g/cm3, 16000 reflections measured (4.898° ≤ 2Θ ≤ 49.99°), 2822 unique (Rint = 0.0249, Rsigma = 0.0196) which were used in all calculations. The final R1 was 0.0484 (I > 2σ(I)) and wR2 was 0.1257 (all data). The absorption maxima of all novel products were evaluated by UV-visible spectroscopy. These well-established structures of all newly prepared chalcone scaffolds with reactive functional groups (i.e. nitrile and 2-propenone) can be exploited as a crucial intermediate in the synthesis of new heterocyclic scaffolds with fluorescence and other applications.

Paramagnetic Re(I) complexes with azolyl-nitroxide ligands

A one-stage synthesis of paramagnetic Re(I) compounds based on the reaction of [Re(CO)5Br] with spin-labeled N-donor heterocycles was developed. Nitronyl nitroxide derivatives of 1H-imidazole (L1), 1H-pyrazole (L2), di(1H-pyrazol-1-yl)methane (L3) and 4-methyl-2-(1H-pyrazol-1-yl)quinoline (L4) can easily substitute two coordinated CO molecules in [Re(CO)5Br], resulting in a series of paramagnetic fac-[Re(CO)3(Li)nBr]·xSolv complexes. Single crystal XRD studies showed that the paramagnetic L1-L4 ligands are coordinated by Re(I) through the imine atoms N of the heterocycles. According to SQUID measurements and EPR spectroscopy data, magnetic behavior of [Re(CO)3(L1)2Br] (1), [Re(CO)3(L2)2Br] (2), and [Re(CO)3(L3)Br] (3) complexes are typical for biradicals, while [Re(CO)3(L4)Br] (4) is typical for monoradical. The combination of Re(I) therapeutic properties and contrasting characteristics of nitroxide radicals in diagnostic magnetic resonance imaging, stability and simplicity of synthesis make [Re(CO)3(Li)nBr] valuable model objects for material design for theranostics purposes.

Fabrication, structural, thermo-mechanical and opto-electrical behavior of anthranilamide compound

Anthranilamide (AAM) compound were fabricated via an alcoholic solvent assisted slow evaporation at room temperature for investigating the multi functional device applications. The solubility test was performed with different concentrations of AAM salt dispersed in 100 mL ethanol solvent to understand the crystallization process of fabricated material. The cell parameters, and diffraction peaks of the title compound were collected through nondestructive tool like single crystal XRD and powder XRD studies, and thus results showed the monoclinic structure. The fabricated material’s functional group, thermal stability, and hardness behavior were tested by various tool viz FT-IR, TG-DTA, and Vickers hardness analysis. With the aid of UV–vis–NIR spectrum, and frequency conversion test technique, optical transmittance and double harmonic generation efficiency values are detected to be 92% and 4.1 mV. Using electrical studies, the dielectric parameters and specific conductance of the title compound values are varied by applying a low frequency to a high frequency region at different temperatures (313, 323, and 333 K).

Growth, structural characterization, DFT study, and magnetic properties of the NdAuIn crystal

A crystal of NdAuIn was successfully grown using the optical floating zone technique. Single-crystal and powder XRD studies confirmed that NdAuIn adopts a hexagonal ZrNiAl-type structure. Comparative analysis of the crystal morphology was performed using the Bravais-Friedel, Donnay-Harker (BFDH) model. DTA analysis revealed that the NdAuIn phase melts congruently at 1136°C. The DFT-calculated enthalpy of formation is −774.192 meV/atom. A thermal expansion coefficient α = 4.1(3) × 10−5 K−1 was derived from the single crystal XRD measurements at 100, 200, and 300 K. The Sommerfeld coefficient γ of 1.262 (mJ/mol × K2) derived from the DFT calculations and the distribution of the density of electronic states, predict metallic conductivity for NdAuIn. The analysis of the charge density difference and Bader charge analysis show that the NdAuIn compound might be treated as polar intermetallic with negatively charged [AuIn]n− and positively charged Ndn+ sublattices. Magnetization measurements with the field parallel and perpendicular to the six-fold axis of the crystal revealed that NdAuIn is a Curie-Weiss paramagnet down to 25 K with an effective magnetic moment of ∼3.62 μB/Nd, which corresponds to the Nd3+ ion. The compound exhibits antiferromagnetic ordering at TN ∼2.4 K.

Monomeric and dimeric cadmium(II) complexes of N4-phenyl semicarbazones: Spectral features, thermogravimetric analysis, DFT study and crystal structure of a bromido bridged complex

Seven cadmium(II) complexes ([Cd(HPySc)Br2] (1), [Cd(HPySc)(OAc)2]·3H2O (2), [Cd(HPySc)Cl2] (3), [Cd(PySc)N3] (4), [Cd(BpSc)(OAc)] (5), [Cd(HBpSc)Cl2] (6), and [Cd2(BpSc)2Br4]) (7) were synthesized using two semicarbazone ligands (HPySc and HBpSc) and characterized by elemental analyses, IR, UV–Vis, thermogravimetric analyses, conductance and single crystal XRD studies. It is found that all the complexes are non-electrolytes in nature and one of the compounds has three molecules of lattice water in the complex. Single crystal study of the complex 7 exhibits a binuclear centrosymmetric structure with a distorted octahedron arrangement around the cadmium(II) centre with Cd⋯Cd non-bonding distance of 4.0809(14) Å. A two-dimensional supramolecular hydrogen bonding network with a zig-zag arrangement is found in the crystal system supported by means of a non-classical hydrogen bonding. DFT calculations reveal that the dimeric complex is the softest and having high chemical reactivity, low stability and high polarizability compared to the other complexes. The NPA and charge distribution analysis indicate that the complexes have significant coordinating sites and potential preferred electron donor sites to metal centers.

Orthovanillin azine ester as a potential functional material for organic electronic devices

The present study reports the synthesis of OVAE, an ester of ortho-vanillin azine, and its structural characterization using spectral and single crystal-XRD studies. Intermolecular interactions of OVAE are investigated using the Hirshfield surface analysis, 3D Hirshfield surface maps, 2D fingerprint plots, and electrostatic energy frameworks. Good thermal stability in thermogravimetric analysis, irreversible redox peaks in electrochemical studies, high carrier concentration and dielectric constant in electrical measurements, uniform films observed upon surface morphology examination, fabrication of a diode, the obtained current-voltage characteristics, dielectric constant and frequency-dependent AC conductivities directed towards the use of OVAE as a potential semiconducting functional material in suitable electronic devices. Based on cyclic voltammetry and AC impedance response, the performance of OVAE as an electrode material is explored by constructing a supercapacitor, which exhibited a specific capacitance of 56 Fg−1 at 10 mV s−1.

Synthesis, crystal structure, DNA binding, molecular docking, DFT, Hirshfeld surface analysis, and cytotoxicity of copper (II) complex with malonamide and 2,9-dimethyl-1,10-phenanthroline

A new copper (II) complex, [Cu(dmp)(malon)(H2O)](NO3)2 where malon = malonamide and dmp = 2,9-dimethyl-1,10-phenanthroline, has been synthesized and characterized by elemental analysis, FT-IR, UV–Visible and single crystal XRD techniques. The complex was crystallized in a monoclinic system with space group P21/n. Single-crystal XRD studies have established that the copper (II) complex cation has a distorted square-pyramidal geometry, with Jahn-teller distortion occurring in the CuN2O3 core. The DFT/UB3LYP/LANL2DZ level of theory was used to optimize the structure of the present complex. The essential interactions within the crystal structure that lead to molecular packing were identified using Hirshfeld surface analysis. UV–Visible absorption titration, fluorescence, cyclic voltammetry, and viscometric titration studies were used to study the interactions of the present complex with calf thymus DNA (CT-DNA) and propose a partial intercalation binding mechanism. The complex demonstrated strong cytotoxic effects against the human hepatocellular carcinoma cell line (HepG2), and it was discovered to have effective antibacterial and antifungal properties. The efficient binding of the copper (II) complex was observed from molecular docking analysis.

Coordination attitude of benzothiazole hydrazone in ruthenium(II) complexes: Catalytic applications on direct formation of imines via acceptorless dehydrogenative process

New Ru(II) complexes (1–5) comprising hydrazone of the type [Ru(L1-3)(CO)(PPh3)2]Cl or [Ru(L4-5)H(CO)(PPh3)2] [L1 = (salicyl((2-(benzothiazol-2yl)hydrazono)methylphenol)) (SAL-HBT), L2 = 2-((2-(benzothiazol-2-yl)hydrazono)methyl)-6 methoxyphenol) (VAN-HBT), L3 = naphtyl-2-((2-(benzothiazol-2-yl)hydrazono)methylphenol) (NAP-HBT), L4 = 1-((benzothiazol-2-yl)-2-(furan-2-ylmethylene)hydrazine) (FUR-HBT) or L5 = 1-((benzothiazol-2-yl)-2-(thiophen-2 ylmethylene)hydrazine) (THI-HBT)] have been formulated by reacting [RuHCl(CO)(PPh3)3] with hydrazones in equal molar ratios in ethanol and chloroform medium. The formation of new complexes have been identified by spectral techniques (IR, (1H, 13C &31P) NMR), micro analyses and mass spectrometry. Single crystal XRD study was used to identify solid state structure of the compound 1 and found octahedral geometry around ruthenium metal. The dehydrogenative coupling of alcohol and amine for formation of imines have been performed using the new ruthenium(II) complexes as catalysts.

Structural (XRD) Characterization and an Analysis of H-Bonding Motifs in Some Tetrahydroxidohexaoxidopentaborate(1-) Salts of N-Substituted Guanidinium Cations.

The synthesis and characterization of six new substituted guanidium tetrahydroxidohexaoxidopentaborate(1-) salts are reported: [C(NH2)2(NHMe)][B5O6(OH)4]·H2O (1), [C(NH2)2(NH{NH2})][B5O6(OH)4] (2), [C(NH2)2(NMe2)][B5O6(OH)4] (3), [C(NH2)(NMe2)2][B5O6(OH)4] (4), [C(NHMe)(NMe2)2][B5O6(OH)4]·B(OH)3 (5), and [TBDH][B5O6(OH)4] (6) (TBD = 1,5,7-triazabicyclo [4.4.0]dec-5-ene). Compounds 1-6 were prepared as crystalline salts from basic aqueous solution via self-assembly processes from B(OH)3 and the appropriate substituted cation. Compounds 1-6 were characterized by spectroscopic (NMR and IR) and by single-crystal XRD studies. A thermal (TGA) analysis on compounds 1-3 and 6 demonstrated that they thermally decomposed via a multistage process to B2O3 at >650 °C. The low temperature stage (<250 °C) was endothermic and corresponded to a loss of H2O. Reactant stoichiometry, solid-state packing, and H-bonding interactions are all important in assembling these structures. An analysis of H-bonding motifs in known unsubstituted guanidinium salts [C(NH2)3]2[B4O5(OH)4]·2H2O, [C(NH2)3][B5O6(OH)4]·H2O, and [C(NH2)3]3[B9O12(OH)6] and in compounds 1-6 revealed that two important H-bonding R22(8) motifs competed to stabilize the observed structures. The guanidinium cation formed charge-assisted pincer cation-anion H-bonded rings as a major motif in [C(NH2)3]2[B4O5(OH)4]·2H2O and [C(NH2)3]3[B9O12(OH)6], whereas the anion-anion ring motif was dominant in [C(NH2)3][B5O6(OH)4]·H2O and in compounds 1-6. This behaviour was consistent with the stoichiometry of the salt and packing effects also strongly influencing their solid-state structures.

Solid state synthesis, thermal, spectral, optical, crystal structure and atomic packing studies of 2-(3-Hydroxyphenyl)-2,3-dihydroquinazolin-4(1H)-one

The environment friendly solid state synthesis is adopted for the synthesis of molecular complex, 2-(3-Hydroxyphenyl)-2,3-dihydroquinazolin-4(1H)-one, (ANHB) with utmost yield. The phase diagram (PD) of anthranilamide (AN) ─ 3-hydroxybenzaldehyde (HB) system gives the compositional behavior of composites in the entire range, and has identified the formation of two eutectics and a molecular complex. The novelty and structural behavior of ANHB was studied using FTIR, NMR, UV–vis, fluorescence, DSC and PXRD techniques. The various thermodynamic characterizations of eutectics and complex are done using the heat of fusion values obtained from DSC. The single crystal XRD (SCXRD) and atomic packing studies of grown ANHB crystal infer that ANHB crystallizes in centro-symmetric triclinic space group P 1¯ with two molecules in the asymmetric unit and four molecules in the unit cell. The synthesized complex shows fluorescence emission in visible region.

Studies of novel benzofuran based chalcone scaffolds: A dual spectroscopic approach as selective hydrazine sensor

A crucial role and scientific attention have been shown by chalcone scaffold in development of science and technology. Owing to their importance, the design and development of innovative chalcone structures has been continued topic of research. This article reports the novel chalcone molecules resulting from benzofuran-2-carbaldehyde and various aromatic carbonyl compounds. The use of two different catalysts, KOH and pyrrolidine which accelerates the Claisen–Schmidt condensation reaction dramatically under mild reaction conditions are disclosed. This study reveals pyrrolidine as more efficient catalyst over KOH. Structures of all prepared molecules are well established by various spectral and Single Crystal XRD studies. Selectively-one of the prepared chalcone is investigated for hydrazine sensing study with dual spectroscopic approaches. Detailed processes with working pH range, sensing selectivity among other analytes, soil sample tests are developed and demonstrated with excellent selectivity for hydrazine. The possible mechanism for the detection of hydrazine is also confirmed by spectral analysis and discussed here. These approaches offer straightforward strategy to achieve the high selectivity towards hydrazine and enlightening further development of hydrazine probes for real time applications.

Synthesis and structural characterization of palladium pincer complexes: Sustainable synthesis of benzothiazoles

An efficient Pd(II)N^N^S pincer type catalysts‐promoted sustainable construction of pharmaceutically important benzothiazole derivatives from primary alcohols and 2‐aminothiophenol via acceptorless dehydrogenative coupling (ADC) method has been described. The newly synthesized ligand L2 and the Pd(II) complexes in addition to L1 and L3 were characterized by analytical and Fourier transform infrared spectroscopy (FT‐IR), UV–visible (UV–vis), and nuclear magnetic resonance (NMR) spectral techniques. Further, the ORTEP views of the complexes 2 and 3 were established by a single crystal XRD study, which evidenced the coordination of the thiosemicarbazone ligands and disclose the square‐planar geometry around the Pd(II) ion. The present homogeneous catalytic system involves synthesizing a range of benzothiazoles via C−S and C−N bond formation with excellent yields up to 93%. The described methodology employs a sustainable, highly abundant, and inexpensive alcohol as starting material using 1 mol% catalyst loading, and water and hydrogen gas are the only by‐products. Furthermore, a plausible mechanism involving in situ aldehyde formation via dehydrogenation of primary alcohols has been proposed. A large‐scale synthesis of 2‐(4‐methoxyphenyl)benzo[d]thiazole illustrates the synthetic utility of the present catalytic protocol.

Growth, characterizations and nonlinear optical studies of dimethylamine substituted anthracene chalcone single crystals

We report the structural, thermal, linear and nonlinear optical (NLO) properties of a newly grown anthracene based chalcone single crystal, (2E)-1-(anthracen-9-yl)-3-[4-(dimethylamino)phenyl]prop-2-en-1-one (abbreviated as DA-ANC). The chalcone was synthesized by Claisen-Schmidt condensation reaction and the single crystals were grown by slow evaporation of solution growth technique. Single-crystal XRD, NMR (1H & 13C), FT-IR, UV-Vis-NIR spectroscopies, TG/DTA, and computational DFT studies were performed to characterize the crystals. The intermolecular interactions were described by Hirshfeld surface analysis (HSA). The third-order NLO properties of DA-ANC were studied by Z-scan technique using CW-DPSS laser at 532 nm. Open aperture Z-scan exhibits strong two-photon assisted reverse saturation absorption (RSA) with two-photon absorption (TPA) coefficient (β) 6.9 × 10−5 cmW−1. Closed aperture Z-scan reveals the negative nonlinear refraction arising due to self-defocusing effect with nonlinear refractive index (n2) coefficient -1.31 × 10−8 cm2W−1. The optical limiting behavior based on TPA was performed and limiting-threshold was evaluated to be 6.47 kJ cm−2. The obtained one-photon and two-photon figures of merit satisfied the conditions of all-optical switching. The results show that DA-ANC can be a potential candidate for NLO applications.

STRUCTURAL INVESTIGATION AND HIRSHFELD SURFACE ANALYSIS OF N-(3-CHLORO-4-METHYLPHENYL)-2-(3-NITROBENZAMIDO)BENZAMIDE

A new synthesis of N-(3-chloro-4-methylphenyl)-2-(3-nitrobenzamido)benzamide was developed in acetic acid as a solvent using the reaction of 3-choloro-4-methylaniline, and 2-(3-nitrophenyl)-4H-benzo-[1,3]oxazin-4-one. This method proved to be efficient in the synthesis of the bis amide compound in good yields and purity. The compound, C21H16ClN3O4, was characterized by single-crystal XRD, IR, 1H NMR, and 13C NMR spectroscopic studies. In the crystal, the molecules are linked by N–H···O and C–H···O hydrogen bonds. There are also weak π···π interactions in the compound form a layer structure parallel to the bc plane. In addition, Hirshfeld surface analysis was carried out to investigate the location of atoms with the potential to form hydrogen bonds and the numerical ratio of these interactions of the compound.

Investigating the Structural and in-Silico Bioactive Properties of a Newly Synthesized Schiff Base Compound through Experimental and Computational Approaches

A new Schiff base compound, (E)–2–[(2–bromophenylimino)methyl]–4,6–dichloro–3–methoxyphenol, was obtained from the condensation reaction of 3,5–dichloro–2–hydroxy–6–methoxybenzaldehyde and 2–bromoaniline in ethanol. Single-crystal XRD studies revealed that the planarity in 3D molecular structure with 5.2° between the two aromatic rings and the crystal packing pattern which is formed by weak intermolecular C―H···O hydrogen bonds and π···π interactions. Geometry optimizations with Gaussian and Slater-type basis sets revealed the molecule's planarity to be significantly distorted at 40.2°. Fingerprint plots and energy frameworks were generated using the Hirshfeld surface analysis approach to better comprehend crystal packing and show the quantity of intermolecular interaction energies. To confirm the suitability of the chosen computational methods, root mean square errors in bond lengths and angles were calculated for the two calculated structures and the experimental structure. Intramolecular charge transfer effects on the molecule have been investigated with the scan and NBO calculations using Gaussian-type basis sets, which were time-saving basis sets in the geometry optimizations. Using experimental FT–IR/UV spectra and calculated ones, molecular electronic configuration outlined in solid-state and solvent media. Molecular docking studies were carried out to examine the compound's potential inhibitory activities against hMAOB protein, and binding energy was found as -8.84 kcal/mol.

Copper(II) chelates derived from an N,N,O-tridentate 2-pyridinecarboxaldehyde-N4-phenylsemicarbazone: Synthesis, spectral aspects, crystal structure, FMO and NBO analysis

Seven novel Cu(II) complexes [Cu(HPySc)Cl2] (1), [Cu2(PySc)2(NO3)2]·H2O (2), [Cu(HPySc)(SO4)]·½H2O (3), [Cu2(PySc)2(OAc)2]·CH3OH (4), [Cu2(PySc)2Br2]·H2O (5), [Cu(PySc)(NCS)]·2H2O (6) and [Cu2(PySc)2(N3)2] (7) with 2-pyridinecarboxaldehyde-N4-phenylsemicarbazone (HPySc) have been prepared and characterized using different analytical and spectroscopic techniques. The complex 6 is expected to be square planar while the other complexes are expected to be square pyramidal arrangement, among these, the geometry of complex 4 has been conformed by single crystal XRD study that it is a dimer and adopts distorted square pyramidal geometry around copper(II) centre. All the complexes are found to be paramagnetic and non-conductive in nature. The semicarbazone ligand is coordinated in neutral form in two of the complexes and in ionic form in others. DFT/B3LYP/6-311g**/LANL2DZ computations of the ligand HpySc (PyCHNNCONHPh) and seven Cu(II) complexes were performed to analyze the FMOs and important electron delocalizations that existed in each compound. Molecular stability and bond strengths have been investigated by applying natural bond orbital (NBO) analysis. All the complexes are more stable than the semicarbazone and the complex 2 is the most electronically stable (-5.160 eV) among the complexes. Furthermore, the semicarbazone is the hardest and complex 5 is the softest than all complexes due to the η values. The calculated energy gap between HOMO and LUMO energies show the variations of nucleophilic and electrophilic reactivity regions in the semicarbazone and in complexes 1-7.

Chemical conversion of CO2 into cyclic carbonates by two Metal–Organic frameworks

Two metal–organic frameworks (MOFs), DDCu and DDMn have been synthesized from a tetracarboxylate ligand by solvothermal method. DDCu contained paddlewheel- [Cu2(COO)4] clusters with axial sites occupied by water molecules and comprised of two types of cages: smaller spherical cages of diameter 9.3 Å and larger ellipsoidal cages of dimensions of 12.4 × 17.7 Å2. While DDMn having bimetallic Mn2(COO)4 clusters with 1D rhombus channels of window size 10.16 × 8.97 Å2. Both the MOFs have open framework structure with solvent accessible void volume 66.5 % and 64.1 % based on the PLATON calculations. The MOFs have been characterized by a series of methods like Single crystal XRD, powder XRD, FT-IR, TGA and N2 adsorption study. Brunauer−Emmett−Teller (BET) surface area of the activated MOFs were 360 and 290 m2/g, respectively. The loosely bound water molecules could be removed to produce unsaturated metal coordination sites that rendered exciting heterogeneous catalytic properties at the metal center of DDCu and DDMn in the fixation of CO2 through the cycloaddition of CO2 with various epoxide. Under ambient conditions (25 °C and 1 atm. CO2 pressure), both the catalyst showed appreciable yields (96 and 91 %) and selectivity (>99 %) for cyclic carbonate formations. Both the catalysts showed very good recycling properties (at least five times).

Studies on synthesis, structural, thermal, optical, spectral and mechanical properties of an inorganic strontium nitrate NLO single crystal

An inorganic NLO single crystal of strontium nitrate (SrN) was successfully grown from an aqueous solution, by slow evaporation technique at ambient temperature. Good transparent SrN crystals were obtained within 2 weeks. Various characterizations were carried out to ensure the application of the grown material. Single crystal XRD study reveals that the crystal shows a cubic structure with a centrosymmetric Pa3¯ space group. The crystalline nature of the compound was confirmed by powder X-ray diffraction. The unit cell dimension of the SrN crystal was found to be, a=b=c=7.8220 Å, and the axial angle is α =β=γ=90°. The average crystalline size of the material was 52 nm. The various functional groups associated with grown crystals have been characterized by FTIR and FT-Raman spectroscopy studies. The lower cut-off wavelength is found to be 320 nm and the band gap energy of the SrN crystal was 3.9 eV. The synthesized crystal exhibits 84% transmittance in the visible region. The grown crystals were thermally stable up to 135 °C. Various mechanical parameters such as microhardness (Hv), work hardening coefficient (n), elastic stiffness (C11), and yield strength (σy) of the grown material have been carried out by the indentation method. The nonlinear refractive index (n2), nonlinear absorption coefficient (β), and third order nonlinear susceptibility (χ(3)) were studied using the Z-scan technique, which involves open and closed aperture measurements with a continuous wave laser of 632.8 nm.