A 3D Coordination Network Built from CuCl(HO) Linear Clusters and Tetrapyridyl Tetrahedral Silane Ligands: Reversible Iodine Uptake and Friedel-Crafts Alkylation Reactions.

A novel three-dimensional coordination network 1 in a new 4,5,6-connected topology (4,5,6T115) built from linear CuCl(HO) clusters and tetrahedral tetrakis(3-pyridyl)vinylsilane ligands is reported. Utilizing a similar tetrahedral ligand, tetrakis(3-pyridyl)ethylsilane, a different framework 2 having CuCl(HO) clusters is obtained in tcs topology. The activated sample of 1 shows an excellent and reversible uptake of I in solid as well as in solution phases owing to the presence of uncoordinated chloride ions and electron rich vinylic groups in it. The I uptake studies on the anion-exchanged samples, of bromide, iodide, and nitrate ions, show a progressive decrease in the adsorption capacity with the sample containing uncoordinated Cl ion showing a maximum uptake of 48.5% and the one with the NO ions exhibiting the lowest uptake of 24.0%. These observations suggest that the halide counterions interact better with I in comparison with nitrate ions and the better I uptake in the presence of Cl ions over the other two halides is due to its smaller size that offers a larger surface area for adsorption. Also, both these compounds were shown to be useful catalysts for the solvent-free syntheses of bis(indolyl)methanes via Friedel-Crafts alkylation reaction.