A new tetra-nuclear sulphate bridged macrocyclic Cu2+ complex (Cu4(SalTCB)4(SO4)2) of salicylaldehyde/dithiocarbazate derived ligand and investigation in colorimetric Cu2+ sensing

A new tetra-nuclear sulphate bridged complex (Cu4(SalTCB)4(SO4)2) was prepared based on benzyl 2-(2-hydroxybenzylidene)-1-methylhydrazine-1-carbodithioate (SalTCB) ligand and characterized by IR, UV–vis spectroscopy, HR ESI-MS, elemental analysis and single crystal X-ray. Solid-state X-ray results revealed that this complex was a sulphate-bridged macrocycle interwoven from four Cu2+ and four ligand molecules. The coordination property of SalTCB to Cu2+ was investigated as selective colorimetric Cu2+ sensor in buffered aqueous-acetonitrile. This sensing property was studied in detail by different spectroscopic analysis. The limit of detection (LOD) for Cu2+ was as low as 0.51 μM. Similarly, ChrDTCB solution based methodology was developed that afforded instant naked eye detection of Cu2+.