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Photophysical and DFT Studies of Cationic Ag(I) Complexes with Thiosemicarbazides Derived from p ‐Toluenesulfohydrazide
Author(s) -
Borges Alice P.,
Gaspari Ana P. S.,
Oliveira Carolina G.,
de Sousa Sinval F.,
da Silva Roberto S.,
Deflon Victor M.,
Machado Antonio E. H.,
Patrocínio Antonio O. T.,
Maia Pedro I. S.
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201800079
Subject(s) - luminescence , denticity , chemistry , cationic polymerization , crystallography , crystal structure , photochemistry , stereochemistry , materials science , polymer chemistry , optoelectronics
Reactions of p ‐toluenesulfohydrazide with R‐isothiocyanates afford new ligands containing both the sulfonamide and thiosemicarbazide moieties ( L R : R=cyclohexyl (Cy) or phenyl (Ph)). L R reacts with AgNO 3 in EtOH in a 2:1 M ratio leading to formation of colourless Ag(I) complexes of general formula [Ag(L R ) 2 ]NO 3 . The crystal structure of a representative complex was determined by crystallographic studies and shows the Ag(I) coordinated by two thiosemicarbazide ligands in a S ‐monodentate coordination mode along with a significant interaction with a nitrate counter‐ion in a bent geometry. Photophysical studies show that both the free ligands and complexes are essentially non‐luminescent at room temperature. At 77 K and glassy media, the silver complexes exhibit a luminescence band in the visible‐light region. Besides, experimental and theoretical analyses suggest the population of the triplet state of these complexes after electronic excitation at around 250 nm. Overall, it was verified that the observed emission of the Ag(I) complexes can be attributed to 3 MLCT radiative decay and that the silver complex with L Ph shows a higher intensity emission than the complex with L Cy .