posted on 2020-03-12, 13:03authored byMadhushree Mitra, Manas Mahapatra, Arnab Dutta, Mousumi Deb, Sayanta Dutta, Pijush Kanti Chattopadhyay, Subhasis Roy, Snehasis Banerjee, Parames C. Sil, Nayan Ranjan Singha
The
nonconventional purely aliphatic scalable and reusable fluorescent
guar gum (GRGM)-grafted-acrylic acid-co-3-(N-isopropylacrylamido)propanoic acid (NIPAPA)-co-N-isopropylacrylamide (GRGM-grafted-1, i.e., 2), was synthesized
via grafting of the optimum amount of GRGM and N–H functionalized in situ protrusion of acrylamido-acid fluorophore-monomer,
i.e., NIPAPA, in multi C–C/N–C/O–C coupled solution
polymerization of two non-emissive monomers in water. The intrinsically
fluorescent noncytotoxic 2 envisaged the excellent potentials
in sensing and removal of Pb(II), security ink, logic function, and
imaging of both cancer and normal cells. The emission intensities
of 2 elevated in concentrated solutions and solid state
because of concentration-enhanced emission and aggregation-induced
enhanced emission (AIEE) characteristics of 2. Additionally,
the emission efficiency of 2 elevated considerably with
increasing GRGM contents and temperatures. The structure of 2, in situ attached fluorophore-monomer, AIEE, cell-imaging
ability, and the superadsorption mechanism were studied employing 1H/13C NMR, X-ray photoelectron spectroscopy, Fourier
transform infrared spectroscopy, ultraviolet–visible spectroscopy,
atomic absorption spectroscopy, thermogravimetric analysis, differential
scanning calorimetry, X-ray diffraction, dynamic light scattering,
high-resolution transmission electron microscopy, fluorescence imaging,
and fluorescence lifetime, along with measuring isotherms, kinetics,
and thermodynamic parameters. The location, geometries, and electronic-structures
of fluorophore, along with absorption and emission properties, of 2 were explored via density functional theory (DFT), time-dependent
DFT, and natural transition orbital analyses. In solution, cyan light-emitting 2 envisaged an average 1.22 ns lifetime in CHCl3. The limit of detection and the maximum adsorption capacity were
2.94 × 10–7 M and 1100.25 mg g–1 at pH 7.0, 303 K, and 1000 ppm, respectively.