Ligimol Louis, D. Suresh Kumar
Abstract: The macrocyclic precursor, 2, 8, 14, 20-tetrakis (4-methoxyphenyl) -4, 6, 10, 12, 16, 18, -22, 24-octahydroxycalix resorcinarene (P1), has been synthesised and characterised using IR, NMR, ESI mass spectroscopy and single crystal X-ray diffraction analysis. P1 crystallizes in the monoclinic crystal system with P21/c space group. Its Hirshfeld surface analysis has been carried out. The other precursor, 2- (pyridin-2-yl) -1H-benzimidazole (P2) and complex precursors, dichlorobis (phenanthroline) ruthenium (II) hydrate (P3) and dichlorobis (2, 2-bipyridine) ruthenium (II) hydrate (P4) are prepared by the modification of reported procedures. The macrocyclic ligand, benzimidazolyl functionalized anisylresorcinarene (L), has been synthesised by the aminomethylation of P1 using P2 and characterised using IR and ESI mass spectrometry. Tetranuclear ruthenium (II) phenanthroline and bipyridine complexes of L have been synthesized and characterized by IR, ESI-MS and electronic absorption spectroscopy. Upon excitation at the excitation maxima the complexes emit from the 3MLCT state at 600 and 624 nm, respectively. The emission band of complexes at 77 K in frozen CH3CN is hypsochromically shifted to 594 and 616 nm, respectively with noticeable increase in the emission intensity and in quantum yields. The complexes show monoexponential decay profile in acetonitrile and have life times of 142 and 200 ns, respectively.
Keywords: Resorcinarene, Ru II complex, 2- pyridin-2-yl -1H-benzimidazole, Hirshfeld surface analysis