Chalcogenolato-bridged rhenium(I)-based ester functionalized flexible dinuclear metallacrown ethers: Cation binding, molecular recognition and docking studies

Abstract

Chalcogenolato-bridged Re(I)-based dinuclear metallacrown ethers [{(CO)3Re(µ-ER)2Re(CO)3}(µ-L)] (E = S, Se; R = tolyl, benzyl) (1–4) were accomplished in a single-step process by the self-assembly of rudimentary dirhenium decacarbonyl, ditolyl disulfide/dibenzyl diselenide, and flexible ditopic polyether tethered ester functionalized pyridyl ligands [L = 4-pyridine carboxylic acid triethylene glycol diester (pcatrgd) and 4-pyridine carboxylic acid tetraethylene glycol diester (pcatgd)]. A series of chalcogenolato-bridged Re(I)-based dinuclear metallacrown ethers were synthesized via oxidative addition of RE−ER unit to the (CO)5Re−Re(CO)5 bond with simultaneous incorporation of flexible ditopic polyether tethered pyridyl linker in an orthogonal fashion. The dinuclear metallacrown ethers 1–4 were characterized by IR, UV−Vis, NMR, and ESI-Mass spectrometric techniques and elemental analysis. The molecular structural elucidation of 1 was carried out using single-crystal X-ray diffraction analysis. Furthermore, the metallacrown ethers 1–4 were investigated for the cation binding potential with monovalent (lithium, sodium, and potassium) and divalent (magnesium and calcium) cations using UV–vis absorption spectroscopic method. In addition, the molecular recognition studies of the metallacrown ethers 1 and 3 as hosts were performed with aromatic amine and alcohol as guests. Moreover, in silico molecular docking studies were carried out for the compounds 1–4 with KasA protein (PDB ID: 2WGD).