Molecules exhibiting a thermotropic liquid-crystalline property have acquired significant importance due to their sensitivity to external stimuli such as temperature, mechanical forces, and electric and magnetic fields. As a result, several novel mesogens have been synthesized by the introduction of various functional groups in the vicinity of the aromatic core as well as in the side chains and their properties have been studied. In the present study, we report three-ring mesogens with hydroxyl groups at one terminal. These mesogens were synthesized by a multistep route, and structural characterization was accomplished by spectral techniques. The mesophase properties were studied by hot-stage optical polarizing microscopy, differential scanning calorimetry, and small-angle X-ray scattering. An enantiotropic nematic phase was noticed for lower homologues, while an additional smectic C phase was found for higher homologues. Solid-state high-resolution natural abundance (13)C NMR studies of a typical mesogen in the solid phase and in the mesophases have been carried out. The (13)C NMR spectrum of the mesogen in the smectic C and nematic phases indicated spontaneous alignment of the molecule in the magnetic field. By utilizing the two-dimensional separated local field (SLF) NMR experiment known as SAMPI4, (13)C-(1)H dipolar couplings have been obtained, which were utilized to determine the orientational order parameters of the mesogen.

The impact of selective rare-earth (RE) additions in ZrO 2 -based ceramics on the resultant crystal structure, mechanical, morphological, optical, magnetic, and imaging contrast features for potential applications in biomedicine is explored. Six different RE, namely, Yb 3+ , Dy 3+ , Tb 3+ , Gd 3+ , Eu 3+ , and Nd 3+ alongside their variations in the dopant concentrations were selected to accomplish a wide range of combinations. The experimental observations affirmed the roles of size and dopant concentration in determining the crystalline phase behavior of ZrO 2 . The significance of tetragonal ZrO 2 (t-ZrO 2 ) → monoclinic ZrO 2 degradation is evident with 10 mol % of RE substitution, while RE contents in the range of 20 and 40 mol % ensured either t-ZrO 2 or cubic ZrO 2 (c-ZrO 2 ) stability until 1500 °C. High RE content in the range of 80−100 mol % still confirmed the structural stability of c-ZrO 2 for lower-sized Yb 3+ , Dy 3+ , and Tb 3+ , while the c-ZrO 2 → RE 2 Zr 2 O 7 phase transition becomes evident for higher-sized Gd 3+ , Eu 3+ , and Nd 3+ . A steady decline in the mechanical properties alongside a quenching effect experienced in the emission phenomena is apparent for high RE concentrations in ZrO 2 . On the one hand, the paramagnetic characteristics of Dy 3+ , Tb 3+ , Gd 3+ , and Nd 3+ fetched excellent contrast features from magnetic resonance imaging analysis. On the other hand, Yb 3+ and Dy 3+ added systems exhibited good Xray absorption coefficient values determined from computed tomography analysis.

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