Coumarin-based luminescent ligand that forms helicates with dicationic metal ions

Abstract

The potentially hexadentate ligand L, which contains two terminal coumarin fluorophores, forms dinuclear double-stranded helicates with dicationic metal ions, giving species of the generic form [M(2)L(2)](4+). In solution the free ligand was fluorescent with emission attributed to the coumarin fluorophores (lambda(em) = 437 nm). The luminescent properties of the corresponding dimetallic helicates complexes were examined and revealed that the Zn(2+) complex demonstrates enhanced emission when compared to the parent ligand, whereas Co(2+), Cu(2+), Cd(2+) and Hg(2+) induce varying degrees of fluorescence quenching. In particular, comparative luminescence measurements at 77 K and room temperature showed that the quenching mechanism for [Cu(2)L(2)](4+) can be attributed to a photoinduced electron transfer. ESI-MS selectivity studies showed that in the presence of a mixture of metal dications no preference for any one metal ion was observed.

Synthesis, spectroscopic studies and inhibitory activity against bactria and fungi of acyclic and macrocyclic transition metal complexes containing a triamine coumarine Schiff base ligand

“…The Schiff base ligands of coumarine and their metal complexes found paramount applications, they are well-known as antioxidants [2], pharmaceutical agents [3] and as luminescent materials [4]. They have pronounced medicinal value as anticoagulants [5], free radical scavengers [6] and as lipoxygenase [7] and cyclooxygenase inhibitors [8].…”

Synthesis of 3-(2-(4-Chlorophenylimino)-3-(4-chlorophenyl)-2,3-dihydrothiazol-4-yl)-2 h-Chromen-2-one via Multicomponent Approach

“…[11,12] The compounds containing the coumarin motif are widely used as additives in food and cosmetic products and known as luminescent materials. [13] They also act as anticoagulants, [14] free radical scavengers, [15] antioxidant, [16] lipoxygenase, [17] and cyclooxygenase inhibitors. [18] Heterocyclic systems having nitrogen and sulfur are very interesting because of their physicochemical properties with relevance to the design of new drugs.…”

A Facile One-Step Multi-Component Approach toward the Synthesis of 3-(2-Amino-4-Thiazolyl)Coumarins by using Trimethylsilyl Isothiocyanate and their Antioxidant and Anti-Inflammatory Activity

“…15,16 The compounds containing the coumarin motif are widely used as luminescent materials. 17 They also act as anticoagulants, 18 free radical scavengers, 19 antioxidant 20 , lipoxygenase, 21 and cyclooxygenase inhibitors. 22 In the literature, numerous methods were reported for the preparation of 4-substituted 2-amino thiazoles based on Hantzsch-type 23 condensation of alpha halo carbonyl compounds with various thioureas.…”