Syntheses, Characterization, and X-ray Crystal Structure of Binuclear Lanthanide Complexes Assembled with Schiff Base and Acetate

Herein we reported the binuclear complexes of the 1-(pyridin-2-yl)-2-(pyridin-2-ylmethylene)hydrazine ligand (HL) [Ln2(HL)2(CH3COO)6].n(H2O) (Ln = Y, Pr, Gd and Er). The binuclear complexes are characterized by IR and physical measurement. Spectroscopic evidence indicated that the Schiff base HL behave an N3 coordination tridentate ligand. The complexes are formulated as [{Ln(1-(pyridin-2-ylmethylidene-kN)-2-(pyridin-2-yl-kN)hydrazine-kN1)(h2-OOCH3)2}{h1:h2:m2-OOCH3}2{Ln(1-(pyridin-2-ylmethylidene-kN)-2-(pyridin-2-yl-kN)hydrazine-kN1))(h2-OOCH3)2}].n(H2O). The structure of the praseodymium complex was elucidated by X-ray diffraction analysis. Suitable crystals were grown by slow evaporation of methanol solution. The asymmetric unit of the compound contains two neutral ligand molecules, two Pr3+ ions, four acetate anions acting in h2-OOCH3 mode, two acetate anions acting in h1:h2:m2-OOCH3 mode, and three uncoordinated water molecules. The praseodymium atom is ten coordinated and the coordination sphere is best described as a distorted bicapped square antiprism. The PrIII···PrIII distance is 4.2777(6) Å and the bridging angle Pr—O—Pr and O—Pr—O are respectively 115.8(3)° and 64.2(3)°. The structure is consolidated by intra and intermolecular hydrogen bond.

Analysis of NMR Spectral Analysis and Molecular Electronic Potential Maps on L-Arginine Phosphate Crystals for Non-Linear Optical Applications

L-Arginine Phosphate (LAP) is a possible material for applications involving nonlinear optical properties. Slow evaporation was used to generate single LAP crystals with a very high degree of transparency from an aqueous solution. The solubility of the pure and doped LAP crystals was measured at different temperatures in the double-distilled water. Natural bond orbital (NBO) research investigated the molecule's stability and charge delocalization. The HOMO-LUMO energies describe the charge transfer between molecules. The electrostatic potential of molecules has been investigated. The correlation found between crystalline perfection and SHG potency was mentioned.

Karakterisasi Karbamazepin Hasil Rekristalisasi Berbagai Pelarut Organik dengan Metode Slow Evaporation

Pendahuluan: Karbamazepin termasuk ke dalam golongan Biopharmaceutical Classification System (BCS) kelas II yang artinya bahwa karbamazepin memiliki permeabilitas membran tinggi dan kelarutan rendah. Rekristalisasi merupakan salah satu cara untuk memodifikasi kristal dalam upaya mengubah sifat fisikokimia dan laju disolusi obat. Tujuan: Penelitian ini bertujuan untuk mengevaluasi sifat fisikokimia karbamazepin melalui rekristalisasi berbagai pelarut. Metode: Pada penelitian ini dilakukan rekristalisasi dengan cara penguapan pelarut menggunakan pelarut etanol, tetrahidrofuran (THF), dan kloroform. Padatan kristal hasil rekristalisasi dikarakterisasi dengan menggunakan spektrofotometri FTIR, difraksi sinar-X (PXRD), dan analisis differential scanning calorimetry (DSC). Selanjutnya dilakukan evaluasi mikromeritik dan uji disolusi. Hasil: Berdasarkan hasil karakterisasi dengan FTIR dan PXRD menunjukan tidak terjadi perubahan struktur kimia dari karbamazepin, tetapi menyebabkan perubahan internal struktur dan perubahan bentuk (polimorfisme) kristal karbamazepin. Hasil evaluasi mikromeritik menunjukkan adanya perubahan sifat fungsional pada padatan kristal hasil rekristalisasi dibandingkan dengan karbamazepin murni, diketahui padatan kristal hasil rekristalisasi etanol menunjukkan sifat mikromeritik yang lebih baik dibandingkan bentuk murni. Uji disolusi menunjukkan bahwa terjadi peningkatan laju disolusi pada padatan kristal hasil rekristalisasi berbagai pelarut dibandingkan dengan karbamazepin murni. Pada padatan kristal hasil rekristalisasi THF memiliki laju disolusi paling tinggi dari pelarut yang lain, yaitu pada menit ke-60 jumlah terdisolusi sebesar 65,09%. Kesimpulan: Proses rekristalisasi karbamazepin dengan pelarut etanol, tetrahidrofuran dan kloroform menghasilkan polimorf baru sehingga sifat fisikokimia padatan hasil rekristalisasi berbeda dibandingkan karbamazepin murni. Berdasarkan hasil uji disolusi in vitro dapat diketahui bahwa karbamazepin hasil rekristalisasi dengan pelarut tetrahidrofuran memiliki laju disolusi yang paling tinggi.

Supramolecular Association between γ-Cyclodextrin and Preyssler-Type Polyoxotungstate

The development of hybrid materials based on polyoxometalates constitutes a strategy for the design of multifunctional materials. The slow evaporation of an aqueous solution of [NaP5W30O110]14− in the presence of γ-Cyclodextrin (γ-CD) led to the crystallization of a K6Na8{[NaP5W30O110]•(C48H80O40)}•23H2O (NaP5W30•1CD) supramolecular compound, which was characterized by single-crystal X-ray diffraction, IR-spectroscopy, thermogravimetric and elemental analyses. Structural analysis revealed the formation of 1:1 {[NaP5W30O110]•[γ-CD]}14− adduct in the solid state. Studies in solution by cyclic voltammetry, electrochemical impedance spectroscopy, 1H NMR spectroscopy, and 31P DOSY, have demonstrated weak interactions between the inorganic anion and the macrocyclic organic molecule.

The Role of Acidity in the Synthesis of Novel Uranyl Selenate and Selenite Compounds and their Structures

Herein, the novel uranyl selenate and selenite compounds Rb2[(UO2)2(SeO4)3], Rb2[(UO2)3(SeO3)2O2], Rb2[UO2(SeO4)2(H2O)]·2H2O, and (UO2)2(HSeO3)2(H2SeO3)2Se2O5 have been synthesized using either slow evaporation or hydrothermal methods under acidic conditions and their structures were refined using single crystal X-ray diffraction. Rb2[(UO2)2(SeO4)3] synthesized hydrothermally adopts a layered 2D tetragonal structure in space group P42/ncm with a = 9.8312(4) Å, c = 15.4924(9) Å, and V = 1497.38(15) Å, where it consists of UO7 polyhedra coordinated via SeO4 units to create units UO2(SeO4)58− moieties which interlink to create layers in which Rb+ cations reside in the interspace. Rb2[(UO2)3(SeO3)2O2] synthesized hydrothermally adopts a layered 2D triclinic structure in space group P1¯ with a = 7.0116(6) Å, b = 7.0646(6) Å, c = 8.1793(7) Å, α = 103.318(7)°, β = 105.968(7)°, γ = 100.642(7)° and V = 365.48(6) Å3, where it consists of edge sharing UO7, UO8 and SeO3 polyhedra that form [(UO2)3(SeO3)2O2] layers in which Rb+ cations are found in the interlayer space. Rb2[UO2(SeO4)2(H2O)]·2H2O synthesized hydrothermally adopts a chain 1D orthorhombic structure in space group Pmn21 with a = 13.041(3) Å, b = 8.579(2) Å, c = 11.583(2) Å, and V = 1295.9(5) Å3, consisting of UO7 polyhedra that corner share with one H2O and four SeO42− ligands, creating infinite chains. (UO2)2(HSeO3)2(H2SeO3)2Se2O5 synthesized under slow evaporation conditions adopts a 0D orthorhombic structure in space group Cmc21 with a = 28.4752(12) Å, b = 6.3410(3) Å, c = 10.8575(6) Å, and V = 1960.45(16) Å3, consisting of discrete rings of [(UO2)2(HSeO3)2(H2SeO3)2Se2O5]2. (UO2)2(HSeO3)2(H2SeO3)2Se2O5 is apparently only the second example of a uranyl diselenite compound to be reported. A combination of single crystal X-ray diffraction and bond valance sums calculations are used to characterise all samples obtained in this investigation. The structures uncovered in this investigation are discussed together with the broader family of uranyl selenates and selenites, particularly in the context of the role acidity plays during synthesis in coercing specific structure, functional group, and topology formations.

Co-crystallization of an organic solid and a tetraaryladamantane at room temperature

Tetraaryladamantanes have proven useful as chaperones for the co-crystallization of small molecules that do not readily crystallize by themselves. The co-crystals are often useful for structure elucidation. Usually, the small molecules are encapsulated in the crystal lattice of the aryladamantane that forms during rapid thermal crystallization. Thus far, co-crystallization has been limited to liquids as guest molecules. Here we report the co-crystal structures of phenol, which is solid at room temperature, with both 1,3,5,7-tetrakis(2,4-dimethoxyphenyl)adamantane (TDA) and 1,3,5,7-tetrakis(2,4-diethoxyphenyl)adamantane (TEO). The co-crystals were obtained from solutions in dichloromethane by slow evaporation or diffusion. The implications for generating other co-crystals of two solids are briefly discussed.

(S)-Alanine ethyl ester tetracyanidoborate, (C5H12NO)[B(CN)4]

The title molecular salt, C5H12NO+·C4BN4 − or (C5H12NO)[B(CN)4], was obtained as single crystals by slow evaporation of a solution of the compound in acetonitrile over several weeks. The asymmetric unit contains two (S)-alanine ethyl ester cations and two tetracyanidoborate anions, which are linked by N—H...N hydrogen bonds. The compound exhibits a relatively low melting point of 110°C and shows a solid–solid phase transition near room temperature (T s–s = 29°C) on the basis of DSC measurements.

RECOVERY OF METALS FROM ELECTROACTIVE COMPONENTS OF SPENT Ni-MH BATTERIES AFTER LEACHING WITH FORMIC ACID

this work describes a route for recovering nickel, cobalt, iron, zinc and lanthanides from spent nickel-metal hydride batteries. Formic acid was used as leachant. Experiments were run at 25-50°C for 1-4 h. Under the best conditions leaching yields surpassed 99 wt.%, except for iron. The insoluble matter contains almost solely iron as iron(III) basic formate. The leachate went through six separation procedures, combining solvent extraction with D2EHPA as extractant, and precipitation reactions. Fe2+ and Zn2+ were extracted together (> 99 wt.%) from the original leachate (pH ~1.5). Yttrium and lanthanides were precipitated as oxalates directly from the raffinate (> 99.9 wt.%) upon addition of sodium oxalate. In the next steps, Mn2+ and Co2+ were extracted with D2EHPA at buffered pH (3 and ~4.8, respectively), after adding NaOHaq. About 10 wt.% of leached Ni2+ was coextracted with Co2+. The remaining Ni2+ was precipitated from the raffinate after addition of aqueous sodium oxalate at pH 6. After precipitation of Al3+ upon addition of NaOHaq. until pH ~8, sodium formate was recovered after slow evaporation of the final aqueous solution at 60oC. It contains ~90 wt.% of the formate present in the leachant.