Synthesis, X-ray Structure, Spectroscopic Properties and DFT Studies of a Novel Schiff Base

Chen, Kew‐Yu; Tsai, Hsing-Yang

doi:10.3390/ijms151018706

Cited by 23 publications

(9 citation statements)

References 85 publications

(89 reference statements)

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“…From E (K*) to E* (K), one can see that the intramolecular hydrogen bond length decreases from 1.89 (1.72) Å to 1.81 (1.65) Å, whereas the other bond lengths do not significantly change. The results clearly provide evidence for the strengthening of the intramolecular hydrogen bond from S 0 → S 1 (S 1 → S 0 ), which is consistent with previous studies [ 51 , 52 , 53 ]. Therefore, there is no question that the decreases of intramolecular hydrogen bond lengths from E (K*) to E* (K) is a very significant positive factor for the ESIPT (GSIPT: ground state intramolecular proton transfer) reaction.…”

Section: Resultssupporting

confidence: 92%

Synthesis, X-ray Structure, Optical, and Electrochemical Properties of a White-Light-Emitting Molecule

Tsai

et al. 2016

Materials

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A new white-light-emitting molecule (1) was synthesized and characterized by NMR spectroscopy, high resolution mass spectrometry, and single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic space group Pnma, with a = 12.6814(6), b = 7.0824(4), c = 17.4628(9) Å, α = 90°, β = 90°, γ = 90°. In the crystal, molecules are linked by weak intermolecular C-H···O hydrogen bonds, forming an infinite chain along [100], generating a C(10) motif. Compound 1 possesses an intramolecular six-membered-ring hydrogen bond, from which excited-state intramolecular proton transfer (ESIPT) takes place from the phenolic proton to the carbonyl oxygen, resulting in a tautomer that is in equilibrium with the normal species, exhibiting a dual emission that covers almost all of the visible spectrum and consequently generates white light. It exhibits one irreversible one-electron oxidation and two irreversible one-electron reductions in dichloromethane at modest potentials. Furthermore, the geometric structures, frontier molecular orbitals (MOs), and the potential energy curves (PECs) for 1 in the ground and the first singlet excited state were fully rationalized by density functional theory (DFT) and time-dependent DFT calculations. The results demonstrate that the forward and backward ESIPT may happen on a similar timescale, enabling the excited-state equilibrium to be established.

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Section: Resultssupporting

confidence: 92%

Synthesis, X-ray Structure, Optical, and Electrochemical Properties of a White-Light-Emitting Molecule

Tsai

et al. 2016

Materials

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“…Vibrational frequencies were calculated via the harmonic approximation to ensure that all optimised structured corresponded to local minima of the potential energy surface. The electronic stabilities of the optimised geometries were computed using the time-dependent density functional theory (TD-DFT) formalism [ 91 , 92 ] and included solvation effects (DMSO) via the polarisable continuum method (PCM) [ 93 , 94 , 95 ], using the same basis set.…”

Section: Methodsmentioning

confidence: 99%

o-Vanillin Derived Schiff Bases and Their Organotin(IV) Compounds: Synthesis, Structural Characterisation, In-Silico Studies and Cytotoxicity

Yusof

Latif

Tahir

et al. 2019

IJMS

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Six new organotin(IV) compounds of Schiff bases derived from S-R-dithiocarbazate [R = benzyl (B), 2- or 4-methylbenzyl (2M and 4M, respectively)] condensed with 2-hydroxy-3-methoxybenzaldehyde (oVa) were synthesised and characterised by elemental analysis, various spectroscopic techniques including infrared, UV-vis, multinuclear (1H, 13C, 119Sn) NMR and mass spectrometry, and single crystal X-ray diffraction. The organotin(IV) compounds were synthesised from the reaction of Ph2SnCl2 or Me2SnCl2 with the Schiff bases (S2MoVaH/S4MoVaH/SBoVaH) to form a total of six new organotin(IV) compounds that had a general formula of [R2Sn(L)] (where L = Schiff base; R = Ph or Me). The molecular geometries of Me2Sn(S2MoVa), Me2Sn(S4MoVa) and Me2Sn(SBoVa) were established by X-ray crystallography and verified using density functional theory calculations. Interestingly, each experimental structure contained two independent but chemically similar molecules in the crystallographic asymmetric unit. The coordination geometry for each molecule was defined by thiolate-sulphur, phenoxide-oxygen and imine-nitrogen atoms derived from a dinegative, tridentate dithiocarbazate ligand with the remaining positions occupied by the methyl-carbon atoms of the organo groups. In each case, the resulting five-coordinate C2NOS geometry was almost exactly intermediate between ideal trigonal-bipyramidal and square-pyramidal geometries. The cytotoxic activities of the Schiff bases and organotin(IV) compounds were investigated against EJ-28 and RT-112 (bladder), HT29 (colon), U87 and SJ-G2 (glioblastoma), MCF-7 (breast) A2780 (ovarian), H460 (lung), A431 (skin), DU145 (prostate), BE2-C (neuroblastoma) and MIA (pancreatic) cancer cell lines and one normal breast cell line (MCF-10A). Diphenyltin(IV) compounds exhibited greater potency than either the Schiff bases or the respective dimethyltin(IV) compounds. Mechanistic studies on the action of these compounds against bladder cancer cells revealed that they induced the production of reactive oxygen species (ROS). The bladder cancer cells were apoptotic after 24 h post-treatment with the diphenyltin(IV) compounds. The interactions of the organotin(IV) compounds with calf thymus DNA (CT-DNA) were experimentally explored using UV-vis absorption spectroscopy. This study revealed that the organotin(IV) compounds have strong DNA binding affinity, verified via molecular docking simulations, which suggests that these organotin(IV) compounds interact with DNA via groove-binding interactions.

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“…Two different synthetic procedures successfully led to the precursors of the desired thiazoles. The resulting thiazoles showed dual‐emissions not only in cyclohexane but also in a solid state with large Stokes shifts, which is one of characteristic features of ESIPT . Further studies on 5‐amino‐1,3‐thiazole‐based fluorophores and their applications as chemo‐ and biosensors are in progress.…”

Section: Figurementioning

confidence: 99%

2‐(2‐Hydroxyphenyl)‐5‐aminothiazoles: Synthesis and Properties Involving Dual Emissions

et al. 2019

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2-(2-Hydroxyphenyl)-5-aminothiazoles were prepared by two different methods to elucidate their photophysical properties. The first synthetic method involved the addition of thioamide dianions derived from secondary thioamides and nBuLi to thioforamides. Alternatively, Pdcatalyzed sequential addition of aromatic groups and diarylamines to commercially available thiazoles led to the precursors of the desired thiazoles. The molecular structures of the resulting thiazoles were determined by X-ray analyses. The thiazoles showed dual-emission in cyclohexane and in the solid state.[a] Prof.

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Synthesis, X-ray Structure, Spectroscopic Properties and DFT Studies of a Novel Schiff Base

Cited by 23 publications

References 85 publications

Synthesis, X-ray Structure, Optical, and Electrochemical Properties of a White-Light-Emitting Molecule

Synthesis, X-ray Structure, Optical, and Electrochemical Properties of a White-Light-Emitting Molecule

o-Vanillin Derived Schiff Bases and Their Organotin(IV) Compounds: Synthesis, Structural Characterisation, In-Silico Studies and Cytotoxicity

2‐(2‐Hydroxyphenyl)‐5‐aminothiazoles: Synthesis and Properties Involving Dual Emissions

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