Copper(II) coordination polymers of arylhydrazone of 1H-indene-1,3(2H)-dione linked by 4,4 '-bipyridineor hexamethylenetetramine: Evaluation of catalytic activity in Henry reaction

摘要

The 1D and the 2D copper(II) coordination polymers [{Cu(kappa N,OO'-L)}(2)(mu-1 kappa N:2-kappa N'-bpy)(2)](n) (1) and [(Cu (mu-1-kappa N,OO':2 kappa O"-L)}(2)(mu-1-kappa N:2 kappa N'-hmt)(n) (2), respectively, were synthesized from copper(II) nitrate and sodium 2-(2-(1,3-dioxo-1H-inden-2(3H)-ylidene) hydrazinyl)benzenesulfonate (NaHL), in the presence of 4,4'-bipyridine (4,4'-bpy) (for 1) or hexamethylenetetramine (hmt) (for 2). 1 and 2 are water soluble and are characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray diffraction. Depending on the neutral linkers, the dianionic ligand L2- displays tri-(in 1) or tetradentate (in 2) binding modes. The Cu2+ in I adopts a distorted N3O2 square-pyramid coordination environment, while in 2 it displays a distorted N2O3 trigonal bipyramid geometry. The catalytic activity of 1 and 2 was evaluated in the diastereoselective Henry reaction of nitroethane with a variety of aromatic and aliphatic aldehydes, in water and in organic solvents. B-Hydroxy nitroalkanes were obtained in high yields (up to 92%), and moderate-to-good syn/anti diastereoselectivities (up to 79:21), in water at room temperature. (C) 2017 Elsevier Ltd. All rights reserved.