ao7b02006_si_003.pdf (4.84 MB)
Functional Molecular System of Bis(pyrazolyl)pyridine Derivatives: Photophysics, Spectroscopy, Computation, and Ion Sensing
journal contribution
posted on 2018-03-13, 08:13 authored by Indravath
K. Naik, Ramakrishna Bodapati, Rudraditya Sarkar, Navendu Mondal, Samar K. DasA new
series of conjugated donor−π–acceptor
type of 2,6-bis(pyrazolyl)pyridine derivatives (compounds IK-(3–9)) have been synthesized via Horner–Wadsworth–Emmons
(HWE) reaction, starting from a common phosphonate precursor and diverse
donor aromatic aldehydes and characterized by routine spectral analysis
including elemental analysis. Compound IK-2, one of the
starting precursors, and molecule IK-3, the first member
of the donor−π–acceptor series, are additionally
characterized by single-crystal X-ray structure determination. Compounds IK-2 and IK-3 are crystallized in P1̅ (triclinic) and P21/c (monoclinic) space groups, respectively. The absorption
maxima in the electronic spectra of the title compounds shift mainly
due to intramolecular charge transfer (ICT) between different donor
(dibutyl and cyclic pyrrolidine) groups and the acceptor moiety [2,6-bis(pyrazolyl)
pyridine]. Solution-state emission spectral studies of all these compounds
show large solvent sensitive behavior with significant amounts of
Stokes shifts. The large solvent dependence of the emission indicates
that the excited state is stabilized in more polar solvents due to
the ICT. All chromophores exhibit solid-state fluorescence behavior
except compound IK-7. The role of the position and nature
of the donor functionalities in the conjugated backbone of overall
donor moiety of compounds IK-(3–9), on the electronic
absorption properties of the title chromophores has been demonstrated,
which has further been corroborated by density functional theory (DFT)
and time-dependent DFT (TDDFT) computational studies. The emission
spectral results of compounds IK-3, IK-5, and IK-7 have also been supported by the DFT and TDDFT
calculations. A fluorescence lifetime study on this series also shows
that the excited states are stabilized in more polar solvents. Finally,
one of the chromophores (chromophore IK-4) in the title
series has been shown to act as a selective molecular sensor (turn-off
switch) for the Cu(II) ion.
History
Usage metrics
Categories
Keywords
compounds IK -3title compounds shiftabsorption maximachromophores exhibitCompounds IK -2time-dependent DFTdonor moietyCompound IK -2cyclic pyrrolidinesingle-crystal X-ray structure determinationmolecule IK -3Functional Molecular Systemtitle chromophoresIK -7fluorescence lifetime studychromophore IK -4HWETDDFT calculationsintramolecular charge transfertitle seriesIK -3Stokes shiftsfluorescence behaviorturn-off switchspace groupscompounds showcompound IK -7absorption propertiesdonor functionalitiesICTphosphonate precursor
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC