Slow Solvent Evaporation Technique Research Articles

Physio-chemical and biological Characterizations of 4 Bromo – 4'Chloro Benzylidene Aniline μ-crystals for Engineering Utilities

4 Bromo—4’Chloro Benzylidene Aniline - as per suggestion it is named as 4B4CBA; Schiff based organic material has been synthesized and successfully grown by slow solvent evaporation technique. The orthorhombic crystal system of the grown crystal with space group Pccn is confirmed and cell parameters of the grown crystal of 4B4CBA is found by single crystal X-ray diffraction (XRD) analysis. The forming of the C-Cl and C-Br stretching vibrations at 719 cm−1 and 538 cm−1 in Fourier Transform Infra-Red (FTIR) study reveal the confirmation of 4B4CBA compound. The CHNSO analysis shows the presence of element in the 4B4CBA. The lower cutoff wavelength and wide optical absorption window of 4B4CBA exhibit the suitability of the present material for the projective opto-electronic applications. Nonlinear optical efficiency for different micro-crystalline of 4B4CBA is determined by second harmonic generation (SHG) experiment and is also compared with Potassium Dihydrogen Phosphate - KDP material. The electrical studies confirm that the 4B4CBA crystal possess low dielectric constant values at high frequency region. The experiment of photo-conductivity confirms the nature of the photo-conductivity of 4B4CBA crystal. The Scanning electron microscopy (SEM) analysis reveals the morphology of 4B4CBA crystal.

Third order nonlinear optical, dielectric, photoluminescence and thermal analysis of Gd3+ doped glycine copper chloride (GCC) crystals

In the present investigations, metal-organic third order nonlinear optical (NLO) crystals of glycine copper chloride (GCC) and gadolinium (Gd) doped GCC with molecular formula (C2H5NO2CuCl2)1−x [Gd(NO3)3]x, where [x = 0.05, 0.10, 0.20] have been successfully grown. The growth of these semi-organic crystal compositions has been achieved at room temperature by slow solvent evaporation technique. The crystals exhibit excellent properties which get confirmed by various characterization studies like single crystal X – ray diffraction (SCXRD), powder X – ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet visible spectroscopy (UV – Vis), photoluminescence (PL) spectroscopy, thermal analysis, electrical and nonlinear optical studies. SCXRD confirms that the grown crystal crystallizes in tetragonal crystal system having space group P42/mnm. The PXRD shows the appearance of sharp and strong peaks which refers to the good crystallinity and phase purity of the grown crystals. FTIR was recorded in order to identify various expected functional group. Linear optical behaviour using UV – Vis confirms the compositions to have good optical transmission in the entire visible region and lower cutoff wavelength ranging between 225 and 244 nm which is essential parameter for developing optoelectronic devices. The band gap value comes out to be in the range of 5.43 – 5.53 eV. The grown crystals possess excellent thermal stability. Results of dielectric studies conducted as a function of temperature divulged the electrical properties of crystals. Third – order nonlinear optical (TONLO) response have been observed using Z – scan setup. The calculated TONLO parameters n2, β, and χ(3) shows large value suggests that grown compositions can be used in practical non linear optical device applications.

Structural, optical, thermal, mechanical, SHG and antibacterial properties of organic dyes doped glycine potassium dihydrogen orthophosphate single crystals

The advanced electro-optical materials are highly demanded because of their various uses in recent years. Glycine potassium dihydrogen orthophosphate single crystals are grown using a slow solvent evaporation technique in order to investigate the effects of the organic dyes crystal violet, malachite green, chrysoidine y, alizarin red, and victoria blue on the structural, optical, mechanical, thermal, SHG, and antibacterial properties. The powder XRD study validates the 14-2d space group tetragonal crystal structure. The higher optical bandgap energy and increased optical transparency of the crystal violet and victoria blue dye doped crystals indicate that there are less defects in their crystal lattice. The elemental analysis confirmed the presence of different organic dyes in the GKDP crystal lattice. The dye doping has enhanced the mechanical and optical characteristics of the formed crystals, and are categorised as soft materials. It is found that all dye-doped crystals have improved thermal stability. Malachite green and crystal violet doped GKDP crystals have higher SHG efficiency.

Characterization and properties of a new insensitive explosive co-crystal composed of trinitrotoluene and pyrene

A new energetic co-crystal of trinitrotoluene (TNT) and pyrene (PYRN) with a 1:1 molar ratio was prepared by a slow solvent evaporation technique. Co-crystal physicochemical properties have also been examined using optical microscopy, powder X-ray diffraction, single crystal X-ray diffraction, and differential scanning calorimetry. The results of single-crystal X-ray diffraction and non-covalent interaction calculations showed that non-covalent interactions (donor–acceptor π-π interaction) govern the structures of the TNT:PYRN co-crystal. The experimental and theoretical outcomes supported each other in the study. Thermal stability, impact sensitivity, and detonation performance of the co-crystal were investigated. DSC measurement indicates that the co-crystal has a melting point of 167 °C and a decomposition temperature of 293 °C, indicating outstanding thermal stability. The co-crystal was found to be less impact-sensitive than TNT using the BAM fall hammer instrument. Furthermore, the calculated detonation velocity and detonation pressure of the co-crystal are 5.29 km·s−1 and 8.48 G Pa, respectively. As an outcome, the TNT:PYRN co-crystal may be a promising intermediate energy explosive with low sensitivity and, as such, may be a desirable explosive alternative in the future instead of TNT for low-vulnerability formulations.

Synthesis, Spectroscopic, Optical, and Thermal Characterizations of Zinc (Tris)-Thiourea Sulfate: A Metal-Organic Crystal.

In the current research, Zinc (tris)-thiourea sulfate (ZTTS), a metal-organic crystal, has been synthesized using the slow solvent evaporation technique. Powder-X-ray diffraction (PXRD) analysis, Fourier transform infrared (FT-IR) spectroscopy, UV-Vis spectroscopy, photoluminescence (PL) spectroscopy, and thermal, and second harmonic generation measurements have all been applied to describe the as-synthesized ZTTS crystals. The synthesized samples crystallized in an orthorhombic structure, based on XRD analysis. The functional groups of ZTTS samples were validated by FT-IR analysis. The extensive transparency of ZTTS over the UV-visible spectral region has been confirmed by UV-Vis analysis and the band gap has been estimated as 4.43eV. The photoluminescence spectra exhibit a prominent emission peak around the wavelength of 484nm and significant emission peaks at 444 and 513nm with an excitation wavelength of 250nm. The SHG test illustrates the creation of second harmonic signals from the ZTTS samples. The thermal response of the as-synthesized ZTTS was shown by the TG/DTA measurements. The results suggest that as-synthesized ZTTS crystals could be used as a possible nonlinear optical substance.

Elucidating l-tyrosine crystal phase transitions by Raman spectroscopy and ab initio calculations

We report here the analysis of the vibrational properties of the l-tyrosine crystal by means of Raman spectroscopy, as well as DFT calculations. The structural stability of the sample was also investigated under high pressure. Single crystals were obtained by the slow solvent evaporation technique. X-ray diffraction experiments were performed at ambient pressure and confirmed the crystalline structure. Simulations of tyrosine dimers allowed us to know some lattice modes. Raman spectra were acquired under ambient conditions and confirmed by ab initio calculations. The classification of the Raman modes is presented and as will be shown, the theoretical results agree with the experimental data. In addition, high pressure Raman spectra were measured from ambient pressure up to 5.9 GPa. The pressure-dependent studies showed that this sample undergoes two phase transitions, at approximately 2 GPa and 3.6 GPa. The transition at 2 GPa is characterized by change of bands in the low-wavenumber region of the spectrum and splitting of a mode associated with torsion of NCCC and rocking of NH3. In the phase transition at 3.6 GPa, changes in the lattice modes and variation of dω/dP for modes between 300 and 450 cm−1 are observed. The observed transitions were reversible when the system brought back to ambient pressure. This study is the first on the crystal of the amino acid l-tyrosine subjected to high pressures, allowing the observation and understanding of the structural and vibrational behavior under these conditions, possibly expanding the possibilities of using this material.

Synthesis, structural characterization, Hirshfeld surface and DFT calculations of 2-ethyl-2,4,5-trimethyl-2H-1,3-thiazine-6(3H)-thione

2-Ethyl-2,4,5-trimethyl-2H-1,3-thiazine-6(3H)-thione (1) was synthesized from butanone and carbon disulfide and recrystallized from a 1:1 mixture of ethyl acetate-hexane using the slow solvent evaporation technique. MS, FT-IR, and NMR spectroscopy techniques allowed to confirm the skeleton structure of (1), and its crystal structure was characterized by X-ray diffraction. The powder X-ray diffraction data confirm the phase purity of the crystalline sample. Single-crystal X-ray diffraction analysis indicated that this compound crystallizes in the monoclinic space group P21/n (N° 14), with unit cell parameters: a = 6.3710 (16) Å, b = 11.537 (3) Å, c = 14.292 (4) Å, β = 93.842 (6)°, V = 1048.1 (5) Å3. Compound (1) displays a half-chair conformation and, in addition, has a chiral center that indicates the presence of a racemic mixture. X-ray results were compared with DFTB (density-functional tight-binding) theoretical calculations in the solid state, confirming delocalization of electron density in the S1C1C2C3N1 segment of the ring that alters bond distances. The crystalline packing is stabilized by hydrogen bonds of the type N1–H1··S1, which form infinite chains parallel to the b axis and are described by the graph-set symbol C(6). Finally, an analysis of the Hirshfeld surfaces of the compound, allowed to identify additional interactions of the type C–H···π. The most important contributions to the crystal packing correspond to the interactions H·· H, S · H / H·· S and C·· H / H·· C with values of 59.8%; 32.20% and 6.40%; respectively.

The influence of l-ornithine monohydrochloride on growth and various properties of ammonium dihydrogen phosphate crystals

In the present work, an aim is to investigate the influence of l-Ornithine monohydrochloride (LOMHCl) doping on structural, optical and electrical properties of pure ADP crystals. It is analyzed by following various characterizations. Pure and LOMHCl doped ammonium dihydrogen phosphate (ADP) crystals have been grown by using slow solvent evaporation technique at room temperature in dust free laboratory. The powder XRD patterns show the single phase nature of pure and doped ADP crystals. The average crystallite size and strain are found from X-ray peak broadening analysis. The UV–Vis spectra indicate slight decrement in the transmittance and band gap values of doped ADP crystals. The SHG efficiency of doped ADP crystals found to increase compared to pure ADP and pure KDP. Z-scan analysis shows increased nonlinear optical properties of doped ADP crystals. The dielectric constant and loss plots show usual behavior with respect to frequency and reduction in the values of doped ADP. The Jonscher's power is studied for ac conductivity. The complex impedance and modulus plots show single semicircle for both pure and doped ADP due to grain contribution only. The stretch exponent parameter values indicate the non-Debye type relaxation process.

Growth, optical, mechanical, dielectric properties of UV-nonlinear optical single-crystal of [(NH4) (Cd(NCS)3)]·C12H24O6

Single-crystal of ammonium (18-crown-6-ether) cadmium (II) tri-thiocyanate [(NH4)[Cd(NCS)3]; (ACCTC) has been grown with dimension 8 × 4 × 4 mm3 was grown from aqueous solution via slow evaporation solvent technique. The S-XRD was utilized to determine the grown single-crystal structure, where the crystalline compound of ACCTC adopts to be orthorhombic crystal system with the space group of Cmc21, and the calculated cell parameters are a = 14.7568 Å, b = 15.4378 Å and c = 10.6383 Å, volume V = 2423.54 Å3. The optical lower cut-off wavelength of the title compound of ACCTC is UV–vis-NIR spectra examined 239 nm. Moreover, the laser-induced surface damage threshold (LISDT), Vickers micro-hardness, and dielectric properties have been examined by the grown title compound of ACCTC. Overall, the experimental results suggest that a single-crystal of ACCTC can be the best nonlinear optical material and possess superior power density (Pd) compared to the KDP single-crystal.

Study of crystalline growth, structural characteristics, optical behavior, thermo and dielectric properties of isoniazid single crystal

In this study, isoniazid single crystals were synthesized using solvent mediated followed by slow solvent evaporation techniques for testing the electro-optics application. Powder XRD analysis was used to record several scattering peaks for the obtained grown material, and the presence of scattering peak positions results correlated to the reported scattering peak position of the above title compound’s orthorhombic crystal structure. Further, the single crystal XRD analysis confirmed the orthorhombic crystal system based on the obtained lattice parameters of synthesized crystal. The grown crystal was scanned using an FT-IR analysis, and its chemically attached functional groups were detected in the spectrum. According to UV–visible studies, isoniazid has a transmittance value of more than 90 %. In addition, the transmittance behavior of the grown compound changed significantly depending on its wavelength. The nonlinear optical property study of the grown crystal was characterized, and the results of the second harmonic generation efficiency values correlate with those of standard reference crystal. Thermal stability and melting temperature of the grown crystal were investigated using TG/DTA studies. The temperature vs weight loss plot revealed weight loss in the temperature range of 225 °C to 400 °C for the grown crystal. Using differential thermo gravimetric analysis (DTA), the melting temperature of the synthesized crystal was determined to be 170 °C. The dielectric constant and dielectric loss responses of grown isoniazid crystals are found to be less at high frequencies and increase exponentially at low frequencies due to the presence of polarization effects.

Enchant O[sbnd]H⋅⋅⋅O interactions in hydrated 6-amino-2-methoxypyrimidin-4(3H)one resembles as water flow in the channel: Crystallographic and theoretical investigations

In this present investigation, a hydrated single crystal of new , 6-amino-2-methoxypyrimidin-4(3H)one (AMP) has been grown using slow solvent evaporation technique. The single crystal X-ray diffraction technique has been used to study the structure of pyrimidinone derivative, which discloses the role of two lattice waters molecules in the crystal packing called hydrated 6-amino-2-methoxypyrimidin-4(3H)one (HAMP). These kinds of hydrated forms incorporate noticeable improvements in the crucial physical properties of API molecules, like stability and bioavailability. The crystal structure of HAMP is greatly stabilized by the significant O—H⋯O, N—H⋯O, and N—H⋯N H-bonding (HB) interactions. With the help of DFT computational analysis, molecular geometry and global reactive parameters have been calculated to better understand the molecular properties of HAMP. The Hirshfeld surface (HS) and accompanying 2D fingerprint plots have been used to explore the nature of all of these non-classical HB interactions, as well as their relative roles in creating supramolecular structures. The energy difference between HOMO-LUMO is found to be 5.414 eV which indicates the possibility of a charge transfer in the HAMP molecule. The molecular electrostatic potential (MEP) has been plotted to understand the charge distribution, electrophilic and nucleophilic sites in the HAMP molecule. Moreover, the quantum theory of atoms in molecules (QTAIM) framework, non-covalent interactions (NCI), reduced density gradient (RDG), electron localization function (ELF), and electron density have been used to describe the nature of non-covalent interactions and electron clouds present in the HAMP crystal.

Effect of dye on luminescent and nonlinear optical properties of bis(4-methoxybenzylammonium) tetra-chlorido cadmate (4MBA2CdCl4) perovskite

We report luminescence and optical limiting (OL) applications of pure and doped layered hybrid halide perovskite (LHHP). Rhodamine B (Rh B), an organic laser dye, was doped in bis(4-methoxybenzylammonium) tetra-chlorido cadmate (4MBA2CdCl4). A simple and cost-effective slow solvent evaporation technique was utilized for crystallization of the perovskites. Formation of both pure and doped 4MBA2CdCl4 were confirmed from the X-ray diffraction (XRD) and Fourier transform infrared (FTIR) studies. 4MBA2CdCl4 crystallized as a layered perovskite where organic layers (4MBA+) are sandwiched between the distorted inorganic CdCl4− octahedral layers. The perovskites are thermally stable up to 276 °C and are flexible up to a load of 50 g. Optical absorption of pure perovskite falls in UV region and is highly transparent for visible light. But, inclusion of Rh B reflected a new absorption peak in the visible region. Also, the luminescence under UV excitation of 4MBA2CdCl4 modified due to doping of dye and it exhibit strong golden yellow luminescence. Nonlinear optical (NLO) properties of pure and doped 4MBA2CdCl4 were also studied by Z-scan technique using 785 nm continuous wave (CW) laser. The perovskites exhibited reverse saturable absorption (RSA) and self-defocusing. Further, both perovskites demonstrate optical limiting properties with a low intensity threshold of 0.8 MW/m2. Rh B incorporated 4MBA2CdCl4 exhibit interesting and enhanced photoluminescence and OL behaviours.

Investigation of NPB Analogs That Target Phosphorylation of BAD-Ser99 in Human Mammary Carcinoma Cells

The design and development of a small molecule named NPB [3-{(4(2,3-dichlorophenyl)piperazin-1-yl}{2-hydroxyphenyl)methyl}-N-cyclopentylbenzamide], which specifically inhibited the phosphorylation of BAD at Ser99 in human carcinoma cells has been previously reported. Herein, the synthesis, characterization, and effect on cancer cell viability of NPB analogs, and the single-crystal X-ray crystallographic studies of an example compound (4r), which was grown via slow-solvent evaporation technique is reported. Screening for loss of viability in mammary carcinoma cells revealed that compounds such as 2[(4(2,3-dichlorophenyl)piperazin-1-yl][naphthalen-1-yl]methyl)phenol (4e), 5[(4(2,3-dichlorophenyl)piperazin-1-yl][2-hydroxyphenyl)methyl)uran-2-carbaldehyde (4f), 3[(2-hydroxyphenyl][4(p-tolyl)piperazin-1-yl)methyl)benzaldehyde (4i), and NPB inhibited the viability of MCF-7 cells with IC50 values of 5.90, 3.11, 7.68, and 6.5 µM, respectively. The loss of cell viability was enhanced by the NPB analogs synthesized by adding newer rings such as naphthalene and furan-2-carbaldehyde in place of N-cyclopentyl-benzamide of NPB. Furthermore, these compounds decreased Ser99 phosphorylation of hBAD. Additional in silico density functional theory calculations suggested possibilities for other analogs of NPB that may be more suitable for further development.

RETRACTED: Amino acid based Rosuvastatin cocrystals: Towards the improvement of physicochemical parameters

• Cocrystal construction between rosuvastatin calcium and amino acids. • Structural and In vitro characterization of cocrystals. • Establishment of intermolecular interaction within the cocrystals. • Cocrystals are found to exhibit higher solubility and dissolution rate. The poor physicochemical properties like low solubility and low dissolution rate of rosuvastatin calcium remain as an obstruction for formulation development. In the present investigation, we explore the evolution of rosuvastatin cocrystal, which may offer the synergetic physico-chemical properties of the drug. Cocrystal crafting depends on two possible intermolecular interactions, heteromeric and the homomeric selection of compounds with complementary functional groups are contemplated as a possible cause of supramolecular synthons in cocrystal formation. Specifically, cocrystals of rosuvastatin with L-asparagine and L-glutamine with molar ratio (1:1) were fabricated by using slow solvent evaporation and solvent evaporation techniques. Novel cocrystals of rosuvastatin-asparagine (RSC-C) and rosuvastatin-glutamine (RSC-G) cocrystals obtained by slow solvent evaporation were utilized for preliminary investigation and further scale-up was done by using the solvent evaporation technique. The novel cocrystals showed a new characteristic of powder X-ray diffraction, thermograms of differential scanning calorimetry, 1 H liquid FT-NMR spectra, and scanning electron microscopy. These results signify, the establishment of intermolecular interaction within the cocrystals. In both the novel cocrystals, rosuvastatin was determined to be engaged in the hydrogen bond interaction with the complementary functional groups of L-asparagine and L-glutamine. Compared with the pure rosuvastatin, RSC-C and RSC-G cocrystal showed 2.17-fold and 1.60-fold improved solubility respectively. The dissolution test showed that the RSC-C and RSC-G cocrystal exhibited 1.64-fold and 1.45-fold higher dissolution rate than the pure rosuvastatin in pH6.8 phosphate buffer respectively. Modulation in the chemical environment, improvement in the solubility and dissolution rate demonstrated the benefit of co-crystallization to improve the physicochemical properties of the drug.

Pharmaceutical cocrystals of Efavirenz: Towards the improvement of solubility, dissolution rate and stability

Efavirenz (EFV) is a Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI) class of antiretroviral drug that is included in antiretroviral therapy to treat Human Immunodeficiency Virus (HIV) patients to increase the life-span by avoiding them to develop Acquired Immune Deficiency Syndrome (AIDS). One of the major drawbacks of EFV is its solubility in purified water (0.093 mg/L). In the present work, two cocrystals of EFV using tartaric acid (TAR) and adipic acid (ADP) as coformers that are Generally Recognized as Safe (GRAS) are reported. Both the EFV-TAR and EFV-ADP cocrystals were developed using slow solvent evaporation technique and further characterization of developed cocrystal structures was done by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC) and Powder x-ray diffraction (PXRD) techniques. The SEM photomicrographs indicated that the EFV-TAR cocrystals were in needle shape with smooth surface. Its length ranged from 100 to 300 µm. The EFV-ADP cocrystals were found to be flaky needle shape with rough surface bearing irregular edges whose length ranged about 50–400 µm. The FT-IR spectra of both developed cocrystals confirmed the formation of a hydrogen bond between EFV and coformers by indicating a notable shift in –CO functional group. The DSC and PXRD studies were further confirmed the successful development of a novel crystalline form (Cocrystal). The solubility (25 ± 0.5 °C) of EFV-TAR and EFV-ADP cocrystals were found to be 163 and 107 μg/mL respectively, whereas pure EFV showed 94 μg/mL. The dissolution rate (37 ± 0.5 °C) of EFV-TAR and EFV-ADP cocrystals in 1% sodium lauryl sulphate (SLS) solution demonstrated 1.4 and 1.2 times increment respectively, compared to the pure EFV. The developed EFV-TAR and EFV-ADP cocrystals were found to stable for 6 months in ambient conditions (25 ± 2 °C, 60 ± 5% relative humidity).

A novel chlorocadmate hybrid cocrystal delivering intermolecular charge transfer enhanced nonlinear optical properties and optical limiting

Employing the donor-acceptor configuration of cocrystals, the intermolecular charge transfer enhanced third order nonlinear optical properties and the optical limiting behaviour of a novel chlorocadmate cocrystal Cd 2 Cl 6 OH 2 2 C 4 H 12 N 2 n ( 1 ) are reported. Optimization of crystal growth parameters is discussed to achieve bulk single crystal with reduced crystal defects by slow solvent evaporation technique. The acid hydrolysis of the piperazine molecule during the pH optimization converted it into piperazine-1,4-diium, which is neutralized by Cd 2 Cl 6 OH 2 2 2 - via hydrogen bond interactions. The intermolecular charge transfer responsible for optical nonlinearity in 1 is proved possible by calculating the intermolecular interaction energies at HF/3-21G level of quantum mechanical calculations. The two-photon absorption coefficient measured at different nanosecond pulsed laser intensities is found to vary, which explicitly confirmed sequential 2 PA in 1 . Lower optical limiting threshold of 1 measured under CW and nanosecond pulsed green laser regime ( ( 1.027 ± 0.02 ) × 10 3 Wcm -2 and ( 1.87 ± 0.02 ) × 10 12 Wm -2 respectively) with coherent dielectric, thermal, mechanical, linear absorption and emission properties showed its suitability for an efficient optical limiting device application. • A Novel intermolecular charge transfer cocrystal for NLO applications is reported. • Sequential two-photon absorption was conclusively proved from intensity-dependent β. • Intermolecular charge transfer interactions assisted optical nonlinearity is proved possible in the title material. • Third order nonlinear optical susceptibility (χ (3) ) of title cocrystal is found to be (0.527 ± 0.008) × 10 −6 esu. • Optical limiting threshold of title cocrystal for nano pulsed (100 mJ, 532 nm) and CW (100 mW, 532 nm) laser irradiance are calculated.

Synthesis and Characterization of a (-)-Epicatechin and Barbituric Acid Cocrystal: Single-Crystal X-ray Diffraction and Vibrational Spectroscopic Studies.

The paper presents the contribution of the cocrystallization method in the physicochemical modification of catechins that exhibit low oral bioavailability. This was done to obtain cocrystals for two naturally occurring polyphenolic diastereoisomers (+)-catechin and (−)-epicatechin with commonly used coformers. Due to distinct crystallization behavior, only the (−)-epicatechin cocrystal with barbituric acid in a 1:1 stoichiometry was obtained. The cocrystal of (−)-epicatechin (EC) with barbituric acid (BTA) was prepared by the slow solvent-evaporation technique. The structure and intermolecular interactions were determined by X-ray crystallographic techniques. The analysis of packing and interactions in the crystal lattice revealed that molecules in the target cocrystal were packed into tapes, formed by the O–H···O type contacts between the (−)-epicatechin and coformer molecules. The EC molecules interact with the carboxyl group in the BTA coformer mainly by −OH groups from the benzene ring A. The cocrystalline phase constituents were also investigated in terms of Hirshfeld surfaces. The application of Raman spectroscopy confirmed the involvement of the C=O group in the formation of hydrogen bonds between the (−)-epicatechin and barbituric acid molecules. Additionally, the solubility studies of pure EC and the EC-BTA cocrystal exhibited minor enhancement of EC solubility in the buffer solution, and pH measurements confirmed a stable level of solubility for EC and its cocrystal.

Rosuvastatin cocrystals: an attempt to modulate physicochemical parameters

BackgroundThe meager physicochemical properties like low solubility and low dissolution rate of rosuvastatin calcium remain as an obstruction for formulation development. In the present work, we explore the evolution of rosuvastatin cocrystal, which may offer the synergetic physico-chemical properties of the drug. Cocrystal crafting depends on two possible intermolecular interactions; heteromeric and the homomeric selection of compounds with complementary functional groups are contemplated as a possible cause of supramolecular synthons in cocrystal formation. Specifically, cocrystals of rosuvastatin with l-asparagine and l-glutamine with molar ratio (1:1) were fabricated by using slow solvent evaporation and slow evaporation techniques. Novel cocrystals of rosuvastatin-asparagine (RSC-C) and rosuvastatin-glutamine (RSC-G) cocrystals obtained by slow solvent evaporation were utilized for preliminary investigation and further scale-up was done by using the solvent evaporation technique.ResultsThe novel cocrystals showed a new characteristic of powder X-ray diffraction, thermograms of differential scanning calorimetry, 1H liquid FT-NMR spectra, and scanning electron microscopy. These results signify the establishment of intermolecular interaction within the cocrystals. In both the novel cocrystals, rosuvastatin was determined to be engaged in the hydrogen bond interaction with the complementary functional groups of l-asparagine and l-glutamine. Compared with the pure rosuvastatin, RSC-C and RSC-G cocrystal showed 2.17-fold and 1.60-fold improved solubility respectively. The dissolution test showed that the RSC-C and RSC-G cocrystal exhibited 1.97-fold and 1.94-fold higher dissolution rate than the pure rosuvastatin in pH6.8 phosphate buffer respectively.ConclusionModulation in the chemical environment, improvement in the solubility, and dissolution rate demonstrated the benefit of co-crystallization to improve the physicochemical properties of the drug.Graphical abstract

Crystal growth and properties measurements of nickel doped potassium dihydrogen citrate crystals

Potassium dihydrogen citrate (KDC) is well-recognized food additive and mineral found in various fruits which make it interesting to study its properties under the influence of toxic metal doping. Pure and different mol% Ni2+-doped KDC crystals were grown using slow-solvent evaporation technique at room temperature. The grown crystals exhibits needle-shaped morphology. EDAX analysis reveals apparent concentration of Ni2+ in different mol% Ni2+-doped KDC. Indexing of powder XRD patterns of pure and different mol% Ni2+-doped KDC reveals triclinic symmetry of grown crystals. W–H analysis reveals presence of lattice strain under the incorporation of Ni2+ doping in the host lattice of KDC. Bond assignments corresponding to various functional groups present in grown crystals is studied using the FT-IR spectroscopic study. The modification in thermal stability of KDC due to Ni2+ doping is studied using TGA analysis. The SEM study has shown grain growth in KDC crystal due to Ni2+ doping. The presence of grain, grain boundary effect and relaxation mechanism involved in transport properties of pure and different mol% Ni2+ doped KDC is reported using the Impedance–Modulus spectroscopic studies. Dielectric studies reveal modification in dielectric constant, dielectric loss and a.c. conductivity of KDC due to Ni2+ doping. The structural defect mechanism is well studied using the photoluminescence.

Growth of High-Quality DSTMS Single Crystals with Enhanced Optical Properties for Photonic Applications

Highly efficient organic nonlinear optical stilbazolium crystals of 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS) single crystal were grown by slow solvent evaporation technique using methanol as a solvent. The structure and cell parameters of the grown crystals were derived from single crystal and powder x-ray diffraction analyses, and the optical properties of the grown crystal were analyzed by a UV–Vis spectrophotometer. The band gap of the grown crystal was found to be 2.28 eV. The vibrating modes of functional groups in the grown crystal were identified by FTIR spectroscopy. The dielectric measurement was made as a function of frequency (1 Hz–1 MHz) at different temperatures (50–200°C) in steps of 50°C. The dielectric constant and dielectric loss were found to be strongly dependent on temperature and frequency of the applied electric field. The semicircle in the Cole–Cole plot showed the presence of dielectric relaxation in the crystal with its radius representing the resistance of the crystal. The resistivity and AC conductivity were calculated from the measured dielectric data.