A. Aditya Prasad

Optical, vibrational, NBO, first-order molecular hyperpolarizability and Hirshfeld surface analysis of a nonlinear optical chalcone.

The synthesis of (1E,4E)-1,5-di-p-tolylpenta-1,4-dien-3-one (DTDO) was done and its single crystals were grown by slow evaporation solution technique from 4-methylbenzaldehyde, acetone solution at room temperature. Crystal structure is determined by single crystal X-ray diffraction analysis and reveals that it belongs to the monoclinic system with four molecules in the unit cell (space group C2). The emission of green light from the sample confirms the second harmonic generation (SHG) of the specimen responsible for nonlinear optical property. The various vibration patterns of the specimen have been investigated by Fourier transform infrared and Fourier transform Raman spectroscopy. Optimized molecular geometry, vibrational patterns of DTDO are derived from density functional theory (DFT) calculations and the results are compared with experimental one. The molecular stability and bond strengths were investigated by applying the natural bond orbital analysis. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density with molecular electrostatic potential (MEP). Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gaps were calculated. The other molecular properties like charge transfer are explained using Mulliken population analysis and the first-order molecular hyperpolarizability (β) of the specimen is also estimated and SHG efficiency of DTDO was found to be 3.9 times that of KDP. Fingerprint plots and Hirshfeld surfaces were used to locate and analyze the molecular surface and bonding interactions in various methodologies utilized in the establishment of the relative energies.

Crystal growth, characterization and theoretical studies of 4-aminopyridinium picrate.

Single crystals of 4-aminopyridinium picrate (APP) were grown by slow evaporation of a mixed solvent system methanol-acetone (1:1, v/v) containing equimolar quantities of 4-aminopyridine and picric acid. Structure is elucidated by single crystal XRD analysis and the crystal belongs to monoclinic system with four molecules in the unit cell (space group P21/c) and the cell parameter values are, a=8.513 Å (±0.015), b=11.33 Å (±0.02), c=14.33 Å (±0.03) and β=104.15° (±0.019), V=1340 A(3) (±6) with refined R factors R1=0.0053 and wR2=0.0126. The electron density mapping is interpreted to find coordinates for each atom in the crystallized molecules. The various functional groups present in the molecule are confirmed by FT-IR analysis. UV-visible spectral analysis was used to determine the band gap energy of 4-aminopyridinium picrate. Powder X-ray diffraction pattern reveals the crystallinity of the as-grown crystal and it closely resembles the simulated XRD from the single crystal XRD analysis. Scanning electron microscopy reveals the surface morphology of the grown crystal. Optimized geometry is derived by Hartree-Fock theory calculations and the first-order molecular hyperpolarizability (β), theoretically calculated bond length, bond angles and excited state energy from theoretical UV-vis spectrum were estimated.

Synthesis, crystal growth, characterization and theoretical studies of 4-aminobenzophenonium picrate.

Single crystals of 4-aminobenzophenonium picrate (4ABPP) were grown by slow evaporation of a mixed solvent system methanol-acetone (1:1,v/v) containing equimolar quantities of picric acid and 4-aminobenzophenone. The proton and carbon signals are confirmed by nuclear magnetic resonance spectroscopy. The various functional groups present in the molecule are identified by FT-IR analysis. Optimized geometry, first-order molecular hyperpolarizability (β), polarizability (α), bond length, bond angles and excited state energy from theoretical UV were derived by Hartree-Fock calculations. The complete assignment of the vibrational modes for 4-aminobenzophenonium picrate was performed by the scaled quantum mechanics force field (SQMFF) methodology using potential energy distribution. Natural bond orbital (NBO) calculations were employed to study the stabilities arising from charge delocalization and intermolecular interactions of 4ABPP. The atomic charge distributions of the various atoms present in 4ABPP are obtained by Mulliken charge population analysis. The as-grown crystal is further characterized by thermal and optical absorbance studies.

Synthesis, growth, structure and characterization of potassium lithium hydrogen phthalate mixed crystals

Mixed crystals of lithium-incorporated potassium hydrogen phthalate were grown by the slow evaporation solution growth technique from an aqueous solution containing equimolar quantities of potassium hydrogen phthalate (KHP) and lithium carbonate. The crystal composition, C16H16KLiO11 (PLHP), as determined by single-crystal XRD analysis reveals the coexistence of potassium and lithium in the mixed crystal, further supported by energy dispersive X-ray spectroscopy and atomic absorption spectroscopy. It belongs to the monoclinic system with the space group P21 and the cell parameters a = 9.4866(3) A, b = 6.769(2) A, c = 15.3967(5) A, α = γ = 90°, β = 105.730°(3), V = 951.67(5) A3 and. Z = 2. The relative second harmonic generation (SHG) efficiency measurements reveal that PLHP has an efficiency comparable to that of KHP. The grown crystals were further characterized by single-crystal XRD, FT-IR, SEM/EDS, TGA/DTA, CHN and UV-visible spectral analysis. Hirshfeld surfaces, derived using single crystal X-ray diffraction data, reveal that the close contacts are associated with strong interactions. Fingerprint plots were used to locate and analyze the percentage of hydrogen bonding interactions.

Growth and characterization of 2-amino-5-nitrobenzophenonium picrate crystals

Single crystals of 2-amino-5-nitrobenzophenonium picrate (ANBP) were grown by slow evaporation solution growth technique from a mixed solvent system ethanol–chloroform–acetic acid (1:1:1, v/v). The 1H and 13C signals of the grown crystal are identified by the nuclear magnetic resonance analyses. Fourier transformed infrared spectroscopy confirms the presence of characteristic functional groups present in the grown crystal. Powder X-ray diffraction was carried out to determine the structure and crystallinity. The crystal belongs to monoclinic system. The optical properties of the grown crystals were analyzed by UV–Vis spectroscopy. Thermogravimetric and differential thermal analysis studies reveal no decomposition up to the melting point. The surface morphology of the as-grown crystals was studied by scanning electron microscopy.

Crystal growth, characterization and theoretical studies of alkaline earth metal-doped tetrakis(thiourea)nickel(II) chloride.

The influence of Sr(II)-doping on the properties of tetrakis(thiourea)nickel(II) chloride (TTNC) has been described. The reduction in the intensity observed in powder X-ray diffraction of doped specimen and slight shifts in vibrational frequencies of doped specimens confirm the lattice stress as a result of doping. Surface morphological changes due to doping of the Sr(II) are observed by scanning electron microscopy. The incorporation of metal into the host crystal lattice was confirmed by energy dispersive X-ray spectroscopy. Lattice parameters are determined by single crystal XRD analysis. The thermogravimetric and differential thermal analysis studies reveal the purity of the materials and no decomposition is observed up to the melting point. The nonlinear optical properties of the doped and undoped specimens were studied. Theoretical calculations were performed using the Density functional theory (DFT) method with B3LYP/LANL2DZ as the basis set. The molecular geometry and vibrational frequencies of TTNC in the ground state were calculated and the observed structural parameters of TTNC are compared with parameters obtained from single crystal X-ray studies. The atomic charge distributions are obtained by Mulliken charge population analysis. The first-order molecular hyperpolarizability, polarizability and dipole moment were derived.

Hyperpolarizability, Hirshfeld, and density functional theory computations of a nonlinear optical picrate

GRAPHICAL ABSTRACT ABSTRACT bis(2-nitroaniline) picrate (BNP) single crystals was grown by slow evaporation growth technique using mixed solvent system with methanol–acetone (1:1, v/v) at a constant temperature, and the structure was interpreted by single crystal X-ray, Power Diffraction (XRD) analysis. Inter- and intramolecular hydrogen bonding interactions were interpreted, and crystal cohesion was architectured by N-H···O, O-H···O, C-H···N, H···H, O···O, and π···π staking interactions. All intermolecular interactions occurring in the crystal lattice were calculated using fingerprint analysis. Interaction strengths were graphically illustrated by the Hirshfeld surface analysis. The band gap energy of BNP was estimated by the application of the Kubelka–Munk algorithm. Nonlinear optical behavior was confirmed by the Kurtz–Perry technique. Optimized geometry was derived by the density functional theory calculations. The first-order molecular hyperpolarizability (β) and excited state energies were estimated by the time-dependent density functional theory analysis.

Synthesis, growth, structure and characterization of molybdenum zinc thiourea complex crystals.

Single crystals of molybdenum-incorporated tris(thiourea)zinc(II) sulfate (MoZTS) are grown by the slow evaporation solution growth technique. Crystal composition as determined by single-crystal X-ray diffraction analysis reveals that it belongs to the orthorhombic system with space group Pca21 and cell parameters a = 11.153 (2), b = 7.7691 (14), c = 15.408 (3) Å, V = 1335.14 (4) Å(3) and Z = 4. The surface morphological changes are studied by scanning electron microscopy. The vibrational patterns in FT-IR are used to identify the functional group and TGA/DTA (thermogravimetric analysis/differential thermal analysis) indicates the stability of the material. The structure and the crystallinity of the material were confirmed by powder X-ray diffraction analysis and the simulated X-ray diffraction (XRD) closely matches the experimental one with varied intensity patterns. The band gap energy is estimated using diffuse reflectance data by the application of the Kubelka-Munk algorithm. The relative second harmonic generation (SHG) efficiency measurements reveal that MoZTS has an efficiency comparable to that of tris(thiourea)zinc(II) sulfate (ZTS). Hirshfeld surfaces were derived using single-crystal X-ray diffraction data. Investigation of the intermolecular interactions and crystal packing via Hirshfeld surface analysis reveal that the close contacts are associated with strong interactions. Intermolecular interactions as revealed by the fingerprint plot and close packing could be the possible reasons for facile charge transfer leading to SHG activity.

Influence of Cs(I)-doping on the spectral, thermal, morphological and optical properties of bis(thiourea)zinc(II) chloride crystals

Single crystals of alkali metal caesium(I) doped bis(thiourea)zinc(II) chloride are grown at room temperature by slow evaporation solution growth technique. Powder XRD studies reveal some interesting features in the XRD profiles with changes in intensity patterns in doped specimen due to stress development in the crystal. The incorporation of Cs(I) into the crystal lattice was confirmed by energy dispersive X-ray spectroscopy. Slight shifts in vibrational patterns of doped specimen indicate that the crystal undergoes considerable lattice stress as result of doping. SEM studies of pure and doped samples reveal the external morphology. Thermogravimetric and differential thermal studies reveal the purity of the material and the specimens are stable up to the melting point. The optical studies reveal that absorption is minimum in the visible region and doping influenced the diffuse reflectance spectrum. The band gap energies of the pure and doped specimens were estimated by the application of Kubelka-Munk algorithm.

Crystal growth, structure and characterization of diglycine zinc dipicrate: Centrosymmetric crystal exhibiting second harmonic generation efficiency

GRAPHICAL ABSTRACT ABSTRACT Single crystals of diglycine zinc dipicrate (DZD) were grown by the slow evaporation solution growth technique from ethanol at room temperature. The structure is elucidated by single crystal XRD analysis and it belongs to the triclinic system with centrosymmetric space group Pī. The crystallinity of the material was confirmed by powder X-ray diffraction analysis. The functional groups present in the molecule are identified by FT-IR analysis and the band gap energy is estimated using diffuse reflectance data by the application of Kubelka–Munk algorithm. Investigation of the intermolecular interactions and crystal packing via Hirshfeld surface analysis, based on single-crystal XRD, reveals the close contacts associated with molecular interactions. Fingerprint plots of the Hirshfeld surfaces were used to locate and analyze the percentage of hydrogen-bonding interactions.The data are analysed by combined results of single crystal XRD and electronic structure calculations. Theoretical calculations done by density functional theory(DFT) gives an idea about structure-function relationship. The second harmonic generation efficiency (SHG) is estimated using the Kurtz and Perry technique and it reveals second order nonlinearity. The observation of a centrosymmetric crystal exbiting NLO character is rationalized.