Electrodeposition of aluminium on the copper substrate using two different chloroaluminate ionic liquid electrolytes such as AlCl 3 /1-Butyl-3-methylimidazolium chloride electrolyte (AlCl 3 -BMIC) and AlCl 3 /1-Ethyl-3-methylimidazolium chloride electrolyte (AlCl 3 -EMIC) were studied. Cyclic voltammetry studies reveal the aluminium deposition process follows two steps mechanism in AlCl 3 -EMIC electrolytes and in AlCl 3 -BMIC electrolytes, it follows single-step mechanism. The AlCl 3 -EMIC electrolytes permit wide deposition current density window than the AlCl 3 -BMIC electrolytes for aluminium deposition with good properties. The aluminium deposits obtained from AlCl3-EMIC electrolyte have better surface properties than the deposits obtained from AlCl 3 -BMIC electrolyte. Detailed comparative studies of deposits obtained from these two electrolytes with respect to deposition mechanism, deposition efficiency and deposition current density window were done. The deposit properties such as surface morphology, microstructure and crystal structures were also compared. From this study, we observed the AlCl 3 -EMIC electrolyte gives good quality deposits than AlCl 3 -BMIC electrolyte.

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A photochromic substituted spiropyran (8-methoxy-1,3',3'trimethylspiro[chromene-2,2'indoline]) was successfully synthesized and its structural integrity was ascertained using spectroscopic methods. Owing to the uniquely positioned methoxy and phenolic groups for potential coordination with a metal ion, it was investigated for the recognition of toxic metal ions. The spiropyran derivative responded to the presence of Cu 2 + ions in an aqueous solution by displaying a color change visible to the naked eye (colorless to pink). The color change was witnessed due to the Cu 2 + ion-induced transformation of the closed-form (spiro) of the substituted spiropyran derivative into an open merocyanine (MC) form, which complexes the Cu 2 + ion. The color change was further used for the quantification of Cu 2 + ion concentration in water using a smartphone captured digital images via pixel intensity analysis. The spiropyran derivative displayed 0.24 � 0.01 μM, 0.65 � 0.06 μM (0.61 � 0.06 μM using paper strips) as the LOD for Cu 2 + ions using UV-Visible spectroscopy and digital colorimetry, respectively. The density functional theory (DFT) calculations and Job's plot supported the formation of a 2 : 1 (H: G) complex between the spiropyran derivative and copper ions. The time-dependent DFT (TD-DFT) investigations were also used to understand the color change during the complex formation, which indicated a good correlation between the experimental and theoretical results at the molecular level.

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