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A self-assembled supramolecular cocrystals of (18-crown-6)0.2(5-amino-2,4,6-triiodoisophthalic acid)0.2(H 2 O) (C 12 H 24 O 6 .2(C 8 H 4 I 3 NO 4 )0.2(H 2 O)) have been synthesised from 18-crown-6 (18C6) and 5-amino-2,4,6-triiodoisophthalic acid (5ATIPA) by slow evaporation method. The crystal structure was elucidated by the single crystal X-ray diffraction analysis, and it belongs to a monoclinic system with a centric space group P2 1 /C . Crystal cohesion is facilitated by the existence of intramolecular (N–H···I) and intermolecular (O–H···O, C–H···O) contacts. All of the oxygen atoms in 18C6 interact with the water molecule via bifurcate hydrogen bonds. The FT-IR analysis identifies the distinctive vibrational patterns. The direct band gap energy is estimated as 3.13 eV by Kubelka–Munk algorithm. Through Hirshfeld surface analysis, fingerprint plots are used to locate and quantify the hydrogen bonding interactions between and within molecules. The third-order nonlinear optical susceptibility (χ (3) ) of the grown crystal is 5.98 × 10 −6 esu. The good third-order NLO responses indicate that the title compound qualifies as a good optical material for photonics devices, optical switches, and optical power limiting applications.

Single crystals of (benzene-1,2-dicarboxylic acid-κO)(2-carboxybenzoato-κO) caesium(I), also known as caesium trihydrodiphthalate (CsADP), were successfully synthesized through a controlled hydrothermal reaction between caesium sulfate and phthalic acid in a 1:2 molar ratio. The resulting crystals, grown over 26–28 days, were analyzed using various techniques. FT-IR spectroscopy revealed characteristic vibrational bands, while powder XRD and single-crystal XRD confirmed phase purity and structural properties. CsADP crystallizes in the orthorhombic system with a centrosymmetric space group (P bcn ). The caesium ion is coordinated by ten oxygen atoms, with Cs···O bond lengths ranging from 3.085 to 3.610 Å, forming a distorted bicapped square antiprism geometry. Thermal analysis indicated stability up to 240 °C, while UV–Vis spectroscopy demonstrated transparency, with a bandgap of 4.17 eV. Nonlinear optical (NLO) properties were investigated using Z-scan techniques, revealing reverse saturation absorption and a strong third-order susceptibility, highlighting CsADP as a promising candidate for NLO applications. Hirshfeld surface analysis identified dominant O···H/H···O interactions, contributing to its NLO behaviour. Additionally, molecular electrostatic potential and Mulliken population analysis provided insights into the charge distribution within the structure.

Self-assembled supramolecular cocrystals of 18-crown-6.2(5-aminoisophthalic acid) have been synthesized from 18-crown-6 (18C6) and 5-aminoisophthalic acid (5AIPA) (stoichiometric ratio 1:2). The single-crystal X-ray analysis revealed the crystal structure, indicating a monoclinic system with the centrosymmetric space group C2/ m . The assembly of the supramolecular structure primarily relies on N–H···O and O–H···O interactions. Characteristic functional groups were identified using FT-IR and micro-Raman spectral analyses. Additionally, the diffuse reflectance spectrum estimated a direct bandgap energy of 2.84 eV. The cocrystal exhibited fluorescent emission in the solid state at room temperature as observed in photoluminescence studies. Analysis utilizing Hirshfeld surface and fingerprint plots unveiled close contacts resulting from robust interactions in the crystal packing. The third-order nonlinear optical properties of the crystal grown were determined using a single-beam Z-scan technique.

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 1 H and 13 C 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.

Single crystals of ammonium nickel sulfate hexahydrate, (NH 4 ) 2 Ni(SO 4 ) 2 ·6H 2 O (ANSH), are grown by conventional slow evaporation solution growth technique at room temperature from an aqueous solution containing an excess of urea/thiourea. Structural analysis by single crystal X-ray diffraction analysis reveals that the crystal belongs to monoclinic system with centrosymmetric space group P 2 1 / c and the cell parameters are a  = 6.246(2) Å, b  = 12.45(4) Å, c  = 9.21(2) Å, β  = 106.96°. The powder X-ray diffraction and high-resolution X-ray diffraction studies reveal the crystallinity and crystalline perfection of the grown crystal. Optical absorbance spectrum indicates a discontinuous transmission pattern. An increase in dielectric and conductivity parameters with the increase of temperature at all frequencies is observed. Thermal studies reveal that there is no decomposition up to the melting point. Probable mechanism of facile crystal growth of the title compound in the presence of excess urea/thiourea as inducer is analyzed.

Mixed crystal, potassium zinc vanadium sulphate was grown from an aqueous solution containing equimolar proportions of K 2 Zn(SO 4 ) 2 ·6H 2 O (Tutton’s salt) and VOSO 4 by slow evaporation at room temperature. Single crystal XRD analysis reveals that it belongs to monoclinic system with P 2 1 / c space group, and cell parameters are a  = 9.006, b  = 12.163, c  = 1.36, and V  = 649.6 Å 3 . The co-existence of VO(II)- and Zn in the Tutton’s salt crystalline matrix was confirmed by atomic absorption spectroscopy and energy dispersive X-ray spectroscopy. Scanning electron microscopy exhibits defect centres and crystal voids. The XRD and FT-IR analyses indicate the stress that the mixed crystal undergoes as a result of incorporation of vanadium. Thermal patterns of Tutton’s salt and the mixed crystal are compared. DTA curve exhibited a sharp endothermic peak at 420 °C for the pure K 2 Zn(SO) 4 ·6H 2 O and at 410 °C for the mixed crystal.

Single crystals of di-μ-thioureabis(thiocyanato)cobalt(II), Co(NCS) 2 (tu) 2 (tu—thiourea) are grown by slow evaporation of a mixed solvent system water–methanol (1:1, v/v) containing thiourea, potassium thiocyanate, and cobalt chloride (1:1:0.5) at room temperature. The dark brown plate-like crystals belong to triclinic system with space group P 1 ¯ , and the cell parameters are a  = 3.8469(7) Å, b  = 7.5749(13) Å, c  = 10.1184(17) Å, α  = 92.599(8)°, β  = 98.036(8)°, γ  = 104.132(7)°, V  = 282.15(9) Å 3 , and Z  = 1. The cobalt atom lies at the center of symmetry with four bridging thiourea molecules. The powder X-ray diffraction study reveals the crystallinity of the material. The complex formation is evidenced by the vibrational patterns in Fourier transform infrared spectrum. The scanning electron microscopy study reveals the surface morphology of the metal–thiourea complex. Thermogravimetric and differential thermal analysis shows that the complex is stable up to the melting point. The crystal is further characterized by UV–Vis and mechanical studies.

Single crystals of (2E, 6E)-2-(4-bromobenzylidine)-6-(4-methoxybenzylidine)cyclohexanone are grown by slow evaporation solution growth technique from ethanol at room temperature. The single crystal-X-ray diffraction study reveals that as-grown crystal belongs to triclinic system and the cell parameters are, a  = 9.3720(3) Å, b  = 11.0500(7) Å, c  = 18.1790(3) Å, and V  = 1,734.90(13) Å 3 . The structure and the crystallinity of the material were further confirmed by nuclear magnetic resonance spectroscopy and powder X-ray diffraction analysis. Simulated XRD pattern closely resembles the powder XRD profile with lowered intensities. FT-IR and FT-Raman spectral analyses reveal the various modes of vibrations. The crystal is transparent in the visible region having a lower optical cut-off at ~503 nm with band gap energy of 2.55 eV, estimated by the application of Kubelka–Munk algorithm. Theoretical calculations were performed using the Hartree–Fock method at level with 6-31G( d,p ) as the basis set for to derive the optimized geometry and first-order molecular hyperpolarizability ( β ) values. The as-grown specimens were further characterized by dielectric and mechanical studies.

Single crystals of (2E, 6E)-2-(4-bromobenzylidine)-6-(4-methoxybenzylidine)cyclohexanone are grown by slow evaporation solution growth technique from ethanol at room temperature. The single crystal-X-ray diffraction study reveals that as-grown crystal belongs to triclinic system and the cell parameters are, a = 9.3720(3) Aa, b = 11.0500(7) Aa, c = 18.1790(3) Aa, and V = 1,734.90(13) Aa super(3). The structure and the crystallinity of the material were further confirmed by nuclear magnetic resonance spectroscopy and powder X-ray diffraction analysis. Simulated XRD pattern closely resembles the powder XRD profile with lowered intensities. FT-IR and FT-Raman spectral analyses reveal the various modes of vibrations. The crystal is transparent in the visible region having a lower optical cut-off at ~503 nm with band gap energy of 2.55 eV, estimated by the application of Kubelka-Munk algorithm. Theoretical calculations were performed using the Hartree-Fock method at level with 6-31G(d,p) as the basis set for to derive the optimized geometry and first-order molecular hyperpolarizability ( beta ) values. The as-grown specimens were further characterized by dielectric and mechanical studies.

The eyes are a window to the brain' is a maxim that holds true especially in the intensive care setting. Recognising specific eye signs aids rapid decision-making regarding diagnosis or prognosis. Eye signs play a pivotal role in intensive care for the neurologist. Eye signs have long been considered the best clinical clue for assessment of a comatose patient. In critically ill patients, the recognition of brainstem involvement hinges primarily on eye signs. The ability to recognise and interpret these signs goes a long way towards ensuring proper care of neurological illness in intensive care units. In this article we enumerate the various signs to be assessed in the ocular and periocular structures. We look at the various types of nystagmus and abnormal eye movements which help to localise lesions in the brainstem. This will aid better diagnosis and prognostication. We categorise eye signs as Category 1 or 2 according to whether they are periorbital and ocular signs or oculomotor abnormalities. Category 2 signs are further sub-classified into Category 2a - common and Category 2b - uncommon. Clinical anatomical correlation of specific signs such as ocular dipping has yet to be elucidated. Research that looks into specific eye signs may help with better anatomic correlation and localisation of lesions.