Reactivity of a Cadmium–Terpyridine Complex: [Cd(L1)(NO3)2(H2O)] (L1 = (4′‐(4‐bromophenyl)‐2,2′:6′,2″‐terpyridine)

Abstract

A novel pincer‐type ligand L2 (4′‐(4‐(6‐methoxypyridin‐3‐yl)phenyl)‐2,2′:6′,2″‐terpyridine), a terpyridine derivative, was prepared by Suzuki–Miyaura CC coupling. Under heating conditions in ethanol, ligands L1 (4′‐(4‐bromophenyl)‐2,2′:6′,2″‐terpyridine) and L2 reacted with Cd(NO3)2·4H2O to produce [Cd(L1)(NO3)2(H2O)] (1) and [Cd(L2)(NO3)2(H2O)]·(H2O) (2), respectively. In complexes 1 and 2, the seven‐coordinate cadmium metal is coordinated to one terpyridine ligand, two nitrato ligands, and an aqua ligand. Under heating conditions in acetonitrile at 120 °C, complex 1 was converted into a 1:1 mixture (3) of [Cd2L2(NO3‐κ3O,O′,O″)(NO3‐κ2O,O′)3] (3a) and [CdL(NO3‐κ2O,O′)2] (3b). When complex 1 was treated with 4,4′‐bipyridine (bpy) under hydrothermal conditions, a one‐dimensional linear coordination polymer [[Cd(L1)(bpy)(NO3)](NO3)(H2O)2]∞ (4) was produced. Complex 1 reacted with 4‐((E)‐2‐(pyridin‐4‐yl)vinyl)pyridine (bpe) in ethanol under microwave‐heating conditions to produce a dimeric complex [Cd2(L1)2(bpe)(EtOH)2(NO3)2)]·(NO3)2 (5). Solid‐state photoluminescent spectra of all complexes displayed a ligand‐based π–π* emission band.