Four new coordination polymers have been obtained by the reaction of metal [Zn(II), Cd(II)], 1,10-phenanthroline separately with two carboxylic acids, [biphenyl-4,4′-dicarboxylic acid (4,4′-H 2 BDA),and 4,4′-azodibenzoic acid (4,4′-H 2 ADA)]. The crystal structures of the resulting complexes of type {[Zn(4,4′-BDA) (4) have been elucidated using their single-crystal X-ray diffraction analysis. Their thermal stabilities have been investigated using thermogravimetric analysis. Complexes result in a 2D structure with channel formation. SEM studies show a coordinationinduced effect on their morphology. Grain and flowery morphology of uncoordinated ligands 4,4′-H 2 BDA and 4,4′-H 2 ADA, respectively, changes on coordination with metal salts. SEM micrographs of complexes exhibit ridged surface, cracks of 2 μm width, parallelopiped structure, and feathery appearance for 1, 2, 3, and 4, respectively. Complexes show moderate adsorption of CO 2 gas.

Dielectric measurements of Ho2Ti2O7 and Dy2Ti2O7 cubic pyrochlore show two distinctly defined relaxations around 90K and 36K. The nature and possible origin of these relaxations have been determined. The observed value of critical exponent of Curie-Weiss and Lacroix-Bń́ equation confirms these relaxations are diffuse and show Debye-like behavior. The order of activation energy of Ho2Ti2O7 and Dy2Ti2O7 shows that both relaxations are distinctly related with structural distortion at oxygen sites. Temperature-dependent lattice volume shows deviation from Debye-Grüneisen behavior below 70 K, further confirms the structural origin of both relaxations. An underlying crystal field anisotropy induced splitting of multipolar order parameter is the primary cause of both diffuse relaxations in these spin ices. It has been found that dielectric relaxations depend strongly on the crystal field, which provides a tool to fine tune the dielectric properties of these systems.

Biocompatible nanoparticles, with magnetic cores and optically active shells, acting as multifunctional materials with a core size of 6 nm encapsulated in silver shells of varying thickness were synthesized through a novel single phase microemulsion method. Incorporation of silver shells onto the magnetite core enhances the intensity of the highest luminescence peak observed for magnetite by a significant luminescence enhancement factor. A blue photoluminescence peak observed in the visible region of spectrum brightens further with the increase in the thickness of silver shell. The magnetic properties of these core-shell nanomaterials show superparamagnetic behavior at room temperature, which is a mandatory criterion for MRI contrast enhancement agents. The hyperthermic response of synthesized magnetite nanoparticles elevates its temperature to 43 °C in a sharp span of time, which is above the desired temperature for the therapeutic application of these multifunctional nanomaterials. These excellent optical and magnetic properties, of the material having a size range suitable for cellular uptake, make it a potential candidate for both diagnostic and therapeutic uses in biomedical applications.

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