Page 91 - Book of Abstracts 2020
P. 91
th
8 Biannual Conference on Chemistry - CHEM 08
Molecular Design of Fluorescent Substrates for the
Detection of Metal Ions: A DFT and TD-DFT Investigation
Bashair Abdullah Banaser; Osman I. Osman and Shaaban A. Elroby
Chemistry Department; Faculty of Science, King Abdulaziz University; P.O.Box
80203 Jeddah 21589; SAUDI ARABIA
.
ABSTRACT
The fluorescent behavior of Binuclear Zn(II) complexes with the Schiff
base ligand N,N-bis(2-hydroxybenzilidene)-2,4,6-trimethyl benzene-1,3-
diamine (H2L), as probes for the detection of metal ions (Zn++, Cu++ and
Ag+) has been investigated by Density Functional Theory (DFT) and Time
Dependent Density Functional Theory (TD-DFT) . The eight isomers of the
H2L ligand were optimized using B3LYP/6-311++G** level of theory;
while the H2L-metal complexes were optimized by using B3LYP
functional with LANL2DZ/6-311++G** mixed basis set. The gas-phase and
solvated enol cis isomer (E-CIS) was found to the most stable species with
an energy gap of 4.064 eV. The absorption and emission spectra of E-CIS
isomer and its metal complexes were simulated using B3LYP, CAM-
B3LYP, M062X and ωB97X functionals with a 6-311++G** basis set and
LANL2DZ basis set for metal ions. All levels of theory seem to yield n⟶ ∗
and ⟶ ∗ excitations more or less comparable to the experimental ones.
The absorption spectra of the H2L ligand were redshifted compared to
those of its metal complexes. The fluorescent on-off behavior for the
detection of metal ions was analyzed and supported by Natural Bond
orbital (NBO) technique.
BOOK OF ABSTRACTS CHEM 08 (2020) Page 90
