Rhenium I Manganese I based supramolecular cages tubes and acyclic complexes

Abstract

ABSTRACT: Neutral heteroleptic flexible tetranuclear coordination cages possessing flexible newlinemultiple electron deficient Cand#61485;H donors was self-assembled using Re2(CO)10, newlinecarbonyldiimidazole/1,2,4-triazole, and bis(benzimidazol-1-yl)methane via one pot solvothermal newlineapproach. The cages (1-2) were characterized using various analytical and spectroscopic techniques newlinesuch as ATR-IR, NMR spectroscopy, mass spectrometry, single crystal X-ray diffraction analysis, newlineand fluorescence spectroscopy. The molecular structure of the cages reveals that it consists of a newlinebutterfly-like cyclic core capped with two neutral N-donor ligands lying above and below the cycle. newlineThe semi-flexible neutral donor and bridged imidazolate/tetrazolate units imparts flexibility to the newlinecage. The dynamic behavior of the cage was studied using variable temperature 1H-NMR newlinespectroscopy. The ability of cage 1 to interact with anions of different shapes and sizes was further newlineinvestigated using 1H-NMR and fluorescence spectroscopy. The thermally stable, flexible cage 1 newlinetransforms into restricted cage in the presence of spherical and linear anions, and selectively newlinerecognizes fluoride. The extent of association of anions with 1 was determined using fluorescence newlinespectroscopy. The binding constant values were calculated using Benesi-Hildebrand equation for newline1:1 host-guest stoichiometry. newline