An efficient naphthalimide based receptor for selective detection of Hg2+and Pb2+ions

Naphthalimide based receptor 1 with N-substituted benzothiazole and pyrrolidine subunit is designed, synthesized, and characterized using FT-IR,1H and 13C NMR spectroscopy and mass spectrometry techniques. The receptor 1 exhibits prominent optical response for Hg2+and Pb2+ions allowing the detection of these ions in acetonitrile (ACN). The formation of the receptor 1:cation complexes have been investigated using UV-Vis and fluorescence emission titration. Further, the selectivity of the receptor 1towards Hg2+and Pb2+ ions on the presence of various interfering cations such as Mg2+, Ba2+, Ni2+, Co2+, Cu2+, Ag2+, Fe2+, Fe3+and Cr3+ has been confirmed by UV-Vis and fluorescence spectroscopy. The binding constant between receptor 1 and Hg2+ and Pb2+ was estimated by Benesi-Hildebrand plot and equations. The binding constants have been found to be Ka= 3.43286 ´ 10−6 and Ka= 2.84079 ´ 10−6 M for Hg2+ and Pb2+, respectively. The limit of detection (LOD) for Hg2+and Pb2+by receptor 1are down to 7.44 ´ 10−10 M and 1.26 ´ 10−9 M, respectively. In addition, Job’s plot analysis reveals 1:2 binding stoichiometry between the receptor 1 and Pb2+ and Hg2+ cations.

A Naphthalimide-Benzothiazole Conjugate as Colorimetric and Fluorescent Sensor for Selective Trinitrophenol Detection

Although chemical structural modification of naphthalimides is widely employed for the purpose of sensing explosives, the effects of such modification have been little explored. Herein, we report the design and synthesis of a new naphthalimide-benzothiazole conjugate (1) and its ability to sense various nitrophenols by means of its colorimetric and fluorescent characteristics. Under long-range UV light (365 nm), 1 displayed a color change of its solution from bluish to colorless only upon addition of 2,4,6-trinitrophenol (TNP). Photoluminescence spectroscopy showed quantitative fluorescence quenching by TNP of the emission peaks of 1 at 398 nm and 418 nm due to donor–acceptor electron transfer. The interaction of 1 with TNP was via a cooperative, non-covalent hydrogen-bonding interaction. Receptor 1 exhibited high sensitivity and selectivity towards TNP over various aromatic nitro analytes. The binding constant (K) and Stern–Volmer constant (Ksv) between 1 and TNP were found to be 5.332 × 10−5 M and 2.271 × 106 M−1, respectively. Furthermore, the limit of detection was calculated and found to be as low as 1.613 × 10−10 M

NDI-based small molecules as electron transporting layers in solution-processed planar perovskite solar cells

High-temperature preparation of metal oxide-based electron transporting materials is considered to be a potential obstacle toward the commercialization of perovskite solar cells. Inverted perovskite solar cells can overcome this problem by employing metal-oxide free, low-temperature-fabricated, and solution-processed electron transporting materials. However, the conventionally-used electron transporting materials (e.g. phenyl-C61-butyric acid methyl ester (PCBM)) has several drawbacks including poor morphology control and high cost, which make its application impractical. Thus, scientists are actively searching novel organic small molecules to replace PCBM because these small compounds have tunable frontier molecular orbitals as well as good film morphology control. More importantly, these molecules can be prepared through inexpensive synthesis routes. Herein, we report the synthesis of two novel naphthalenediimide (NDI)-based electron transporting materials (4,4′-(piperazine-1,4-diyl)bis(2,7-dioctylbenzo[lmn]-[3,8]phenanthroline-1,3,6,8(2 H,7 H)-tetraone) (PDPT) and 9,9′-(piperazine-1,4-diyl) bis(4-(4-methylpiperidin-1-yl)-2,7 dioctylbenzo [lmn]-[3,8]phenanthroline-1,3,6,8(2 H,7 H)-tetraone) (PMDPT)), and found that the inverted perovskite solar cells with PMDPT as an electron transporting layer can reach a power conversion efficiency up to 9.2% while the efficiency of PSCs based on PDPT can only approach 7.6%. We believe that this improvement in the efficiency of PMDPT-based PSCs ascribes to the increased number of nitrogen atoms in the framework of PMDPT, which passivates the electron trap centers on the surface of the perovskite layer. This passivation results in less charge recombination, therefore delivering a higher Voc and PCE.MOE (Min. of Education, S’pore

An efficient naphthalimide based receptor for selective detection of Hg²⁺and Pb²⁺ions ^#

1353-1361Naphthalimide based receptor 1 with N-substituted benzothiazole and pyrrolidine subunit is designed, synthesized, and characterized using FT-IR,1H and 13C NMR spectroscopy and mass spectrometry techniques. The receptor 1 exhibits prominent optical response for Hg2+and Pb2+ions allowing the detection of these ions in acetonitrile (ACN). The formation of the receptor 1:cation complexes have been investigated using UV-Vis and fluorescence emission titration. Further, the selectivity of the receptor 1towards Hg2+and Pb2+ ions on the presence of various interfering cations such as Mg2+, Ba2+, Ni2+, Co2+, Cu2+, Ag2+, Fe2+, Fe3+and Cr3+ has been confirmed by UV-Vis and fluorescence spectroscopy. The binding constant between receptor 1 and Hg2+ and Pb2+ was estimated by Benesi-Hildebrand plot and equations. The binding constants have been found to be Ka= 3.43286 10−6 and Ka= 2.84079 10−6 M for Hg2+ and Pb2+, respectively. The limit of detection (LOD) for Hg2+and Pb2+by receptor 1are down to 7.44 10−10 M and 1.26 10−9 M, respectively. In addition, Job’s plot analysis reveals 1:2 binding stoichiometry between the receptor 1 and Pb2+ and Hg2+ cations