HongRu Li

Name: 李红茹; HongRu Li

Organization: Chongqing University

Department: College of Chemistry and Chemical Engineering

Title: Associate Researcher/Professor

Chemicals
References

Synthesis of New Benzotriazole Derivatives Containing Carbon Chains as the Corrosion Inhibitors for Copper in Sodium Chloride Solution

Co-reporter:Yulong Gong;Zhenqiang Wang;Shengtao Zhang;Fang Gao

Industrial & Engineering Chemistry Research December 16, 2015 Volume 54(Issue 49) pp:12242-12253

Publication Date(Web):2017-2-22

DOI:10.1021/acs.iecr.5b02988

In this study, a series of benzotriazole derivatives with various carbon chains (n = 1, 3, 4, 6, 7, 9, 10, 12, 16) were synthesized for the corrosion inhibition of copper in 3.5 wt % (wt %) NaCl solution. The corrosion inhibition efficiencies of these inhibitors in 3.5 wt % NaCl solution for copper were measured by various measurements including the polarization curves, the electrochemical impendence spectroscopy as well as the weight loss method. The inhibition mechanism of these new target molecules were analyzed by the plots of Tafel, Nyquist, and Bode. The corrosion inhibition effect was also evaluated by scanning the copper surface with an electron microscope. The results show that the corrosion of copper in chloride aqueous solution is efficiently inhibited by these new organic inhibitors. Furthermore, the corrosion inhibition efficiencies of the target inhibitors are shown to have much dependence on the carbon chain length attached to the molecular backbone. The inhibitor carrying a 7-carbon chain displays the greatest inhibition efficiency as large as ∼98% at 0.15 mM, while even the poorest inhibitor containing a 2-carbon chain shows ∼60% inhibition efficiency. The adsorption of these new inhibitors on copper was further revealed by analysis of Langmuir isotherms and quantum chemical calculations.

Conjugated dyes carrying N, N-dialkylamino and ketone groups: One-component visible light Norrish type II photoinitiators

Co-reporter:Ge Ding, Chuan Jing, Xiaozhuan Qin, Yulong Gong, Xueping Zhang, Shengtao Zhang, Ziping Luo, Hongru Li, Fang Gao

Dyes and Pigments 2017 Volume 137() pp:456-467

Publication Date(Web):February 2017

DOI:10.1016/j.dyepig.2016.10.034

•Synthesis of new conjugated dyes carrying dialkylamino and ketone groups through multi-step routes.•Visible light photoinitiating properties of these dyes using as one-component photoinitiators studied by photo-DSC.•Efficient visible light photoinitiating polymerization of methyl methacrylate by one-component photoinitiators.•Greater visible light photoinitiating efficiencies of one-component photoinitiators than two-component ones.This work presents new conjugated dyes carrying N, N-dialkylamino and ketone groups for using as one-component Norrish type II visible light photoinitiators. The novel dyes without ketone group were also synthesized to compose two-component visible light photoinitiators for comparisons. The target dyes show the remarkable absorption in visible light region. Photo-differential scanning calorimetry was employed to study visible light photoinitiating polymerization kinetics of methyl methacrylate by new one-component photoinitiators and two-component photoinitiators respectively. The results suggest that the one-component photoinitiators showed much more efficient photoinitiating polymerization of methyl methacrylate than the two-component photoinitiating systems under visible light irradiation. The molecular weight of visible light photopolymer produced by the new photoinitiators was determined. The visible light photoinitiating mechanism of the one-component photoinitiators was studied by absorption and emission spectra, electron spin resonance spectra and cyclic voltammograms analysis.

Aggregation and ESIPT together inspired naked-eye fluorescence color switching of new π-conjugated dyes carrying double proton transfer segments

Co-reporter:Ge Ding, Jihong Su, Xiaozhuan Qin, Yao Lu, Li Ma, Hongru Li, Lingyun Chen, Ziping Luo, Fang Gao

Materials Letters 2017 Volume 186() pp:301-304

Publication Date(Web):1 January 2017

DOI:10.1016/j.matlet.2016.10.030

•Synthesis of new conjugated chromophores carrying double proton transfer segments.•Formation of nano organic aggregation particles in THF/H2O mixed solution.•Naked-eye fluorescence color switching of the aggregates under UV irradiation.•Strong potential application in developing multicolor organic aggregates.New conjugated dye C1 (2, 2′-((5-(2-(4-methoxyphenyl)ethenyl)-benzene-1, 3-diyl)-bis-(nitrilomethylylidene))-diphenol) carrying double proton transfer segments and its reference C2 (N, N′-(5-(2-(4-methoxyphenyl)-ethenyl)-benzene-1, 3-diyl)-bis-(1-phenylmethanimine)) were synthesized. The SEM and TEM images showed that cubic-shaped aggregates of C1 were formed with sizes of 300–500 nm in THF/H2O mixed solution at 12 h. The spectral properties of aggregation states of the molecules in different ratios of THF/H2O were further investigated. The fluorescence emission spectra under different aggregation time intervals indicated that C1 exhibited remarkable aggregation induced emission enhancement. The keto emission of C1 showed an increase firstly and then a decrease with increasing aggregation time. Hence, the enhanced fluorescence color switching from bright yellow to pure blue under UV lamp was observed by our naked eyes. In contrast, C2 could not show obvious AIEE properties under identical experimental conditions. This is the first successful attempt to achieve naked-eye fluorescence chromism of new organic chromophores inspired by aggregation and ESIPT together.

Understanding difficulties of irregular number-membered ring transition states for intramolecular proton transfer in excited state

Co-reporter:Xiaozhuan Qin, Ge Ding, Zhenqiang Wang, Yulong Gong, Fang Gao, Shengtao Zhang, Ziping Luo, Hongru Li

Tetrahedron 2017 Volume 73(Issue 4) pp:403-410

Publication Date(Web):26 January 2017

DOI:10.1016/j.tet.2016.12.026

This study presents a variety of organic dyes with similar molecular structures that could undergo intramolecular proton transfer in excited states via five-, six- and seven-number-membered ring transition states, respectively. In addition, the dyes without proton transfer segments are also synthesized to use as references. X-ray single crystal diffraction, NMR spectra as well as UV/visible spectra suggests the presence of internal hydrogen bond with different strength in the target dyes. The steady and transient fluorescence measurements demonstrate occurrence of excited state intramolecular proton transfer via a six number-membered ring transition state. In contrast, it cannot be processed through five- and seven-number-membered ring transition states of the studied dyes. The molecular geometry optimization of the studied dyes reveals fundamental factors for the difficulties of intramolecular proton transfer in excited states via five- and seven-number-membered ring transition states.

Two intensified fluorescence colors’ switching achieved by branched dye nanoaggregates

Co-reporter:Ge Ding;Yao Lu;Jihong Su;Xiaozhuan Qin;Ziping Luo;Fang Gao;Lingyun Chen

Nanoscale (2009-Present) 2017 vol. 9(Issue 31) pp:11158-11169

Publication Date(Web):2017/08/10

DOI:10.1039/C7NR02169K

In this study, a variety of branched target dyes containing double internal proton transfer segments were synthesized. For comparison, some linear analogs including a single internal proton transfer part were synthesized. The corresponding reference molecules lacking proton transfer segments were also prepared. The properties and aggregation modes of these dye aggregates were investigated on the basis of scanning electron microscopy images, transmission electron microscopy images, dynamic light scattering, X-ray diffraction, UV/visible absorption spectra and fluorescence emission spectra. The results showed that molecular aggregates with the morphologies of nano-scaled rounded or cubic particles of the target branched dyes could be yielded in mixed organic solvent/H2O solution. A remarkable emission enhancement and fluorescence switching process (from bright yellow to luminous pure blue) under 365 nm lamp irradiation was observed for these target branched dye nanoaggregates. However, no aggregates of the reference branched dyes free of hydroxyl groups were formed and no obvious spectral variations were found. In contrast, all the studied linear dyes yielded molecular nanoaggregates in mixed organic solvent/H2O solution, and only intensified single normal blue fluorescence emission was presented. This study provided real examples of some branched organic dye aggregates which were capable of displaying naked-eye enhanced fluorescence color switching under an UV lamp.

Water soluble corrosion inhibitors for copper in 3.5 wt% sodium chloride solution

Co-reporter:Haijun Huang, Zhenqiang Wang, Yulong Gong, Fang Gao, Ziping Luo, Shengtao Zhang, Hongru Li

Corrosion Science 2017 Volume 123(Volume 123) pp:

Publication Date(Web):15 July 2017

DOI:10.1016/j.corsci.2017.05.009

•Synthesis of water soluble corrosion inhibitors for copper in NaCl solution.•Efficient corrosion inhibition nature of the studied inhibitors for copper.•Analyses of adsorption mechanism of the inhibitors on copper surface.In this study, synthesis of water soluble and efficient corrosion inhibitors PBTB carrying single benzotriazole part and PDBTB containing double benzotriazole segments for copper in 3.5 wt% sodium chloride solution was proposed. PDBTB showed greater corrosion inhibition effect than PBTB basing on survey results of polarization curves, impedance spectroscopy and scanning electron microscopy. Adsorption mechanism of the studied inhibitors on copper surface was studied by FT-IR spectra, X-ray photoelectron spectroscopy, X-ray diffraction spectra as well as adsorption isotherm.Download high-res image (106KB)Download full-size image

New AB2 type two-photon absorption dyes for well-separated dual-emission: molecular preorganization based approach to photophysical properties

Co-reporter:Ge Ding, Yao Lu, Yulong Gong, Li Ma, Ziping Luo, Shengtao Zhang, Fang Gao, Hongru Li

Tetrahedron 2016 Volume 72(Issue 22) pp:3040-3056

Publication Date(Web):2 June 2016

DOI:10.1016/j.tet.2016.04.024

A variety of AB2 type new target dyes containing two proton transfer segments (o-hydroxy-phenyl-imino) are presented in this study. Furthermore, the corresponding reference molecules absent of hydroxy or imino groups are provided as well. Dual intramolecular hydrogen bonds in the target dyes are demonstrated by 1H NMR spectra, X-ray single crystal analysis as well as one-photon absorption spectra. Linear emission properties (static and transient emission nature) and two-photon absorption optical properties of these target and reference dyes are determined in various media such as organic solvents, solid phase state as well as PMMA substrate. The results show that the new AB2 type target dyes can efficiently undergo internal proton transfer in the excited states under one-photon irradiation and near-infrared femtosecond laser two-photon irradiation, respectively, and thus they exhibit well-separated dual-emission. The molecular geometry optimization is performed for the analysis of the occurrence of internal proton transfer in the excited states of the target AB2 chromophores.

Efficient enhancement of internal proton transfer of branched π-extended organic chromophore under one-photon and near-infrared two-photon irradiation

Co-reporter:Yulong Gong, Yao Lu, Huiying Ma, Ge Ding, Shengtao Zhang, Ziping Luo, Hongru Li, Fang Gao

Chemical Physics Letters 2015 Volume 619() pp:201-207

Publication Date(Web):5 January 2015

DOI:10.1016/j.cplett.2014.12.005

Highlights

The new branched chromophores bearing with proton transfer segments were synthesized.

Internal H-bonding effect in the ground state of new chromophores is demonstrated.

ESIPT of new chromophores is increased by branched structure under near-IR laser irradiation.

4-Formyl-2-(2H-benzotriazol-2-yl)-phenol: an ESIPT chromophore

Co-reporter:Yao Lu;Yulong Gong;Huiying Ma;Zhenqiang Wang;Haili Li

Science Bulletin 2014 Volume 59( Issue 34) pp:4741-4751

Publication Date(Web):2014 December

DOI:10.1007/s11434-014-0562-5

In the present work, excited state intramolecular proton transfer (ESIPT) emission properties of a new benzotriazole derivative 4-formyl-2-(2H-benzotriazol-2-yl)-phenol (C1) were studied. 4-Formyl-2-(2H-benzotriazol-2-yl)-methoxy-benzene (C2), 4-formyl-2-(2H-benzotriazol-2-yl)-phenyl acetate (C3) and 4-methyl-2-(2H-benzotriazol-2-yl)-phenol (C4) were used as the reference molecules. 1H NMR chemical shift of hydroxy group in C1 was located at more down field than that of C4 or p-hydroxy-benzaldehyde (C5), respectively. C1 showed two absorption bands in the range of 260–400 nm zones in various solvents, while C2 and C3 exhibited single absorption band. The equal molar mixtures of C2/C5 or C3/C5 showed single absorption band. C2 and C3 displayed single fluorescence emission band in various solvents, while C1 exhibited dual emission bands in some strong polar solvents. Furthermore, the second emission band in these strong polar solvents showed the large Stokes shift. The results show that the second emission band of C1 was produced by ESIPT. C2 and C3 could not undergo ESIPT due to no hydroxy group. The geometry optimization calculation of enol and keto forms in the ground and excited states of C1 provided tough theoretical evidences of ESIPT.

New two-photon absorption organic chromophores containing imino and hydroxyl groups: synthesis, ESIPT and chemosensors

Co-reporter:Fang Gao, Xinchao Wang, Hongru Li, Xiaojuan Ye

Tetrahedron 2013 69(26) pp: 5355-5366

Publication Date(Web):

DOI:10.1016/j.tet.2013.04.121

Evidence for Two-Photon Absorption-Induced ESIPT of Chromophores Containing Hydroxyl and Imino Groups

Co-reporter: Dr. Fang Gao;Xiaojuan Ye; Dr. Hongru Li;Xiaolin Zhong ;Qi Wang

ChemPhysChem 2012 Volume 13( Issue 5) pp:1313-1324

Publication Date(Web):

DOI:10.1002/cphc.201100885

Abstract

This paper presents experimental and theoretical investigations into excited-state intramolecular proton transfer (ESIPT) in new chromophores with hydroxyl and imino groups under one- and two-photon excitation. The results show that internal hydrogen bonding exhibits a remarkable influence on the maximum absorption wavelength of 2-[(4′-N,N-diethylaminodiphenylethylene-4-ylimino)methyl]phenol (C1) and 2-[(4′-methoxyl-diphenylethylene-4-ylimino)methyl]phenol (C3). Compounds C1 and C3 exhibit well-separated dual fluorescence emission bands under one- and two-photon excitation. The second fluorescence peaks of C1 and C3 are characterized by much larger Stokes shift than the first normal peaks (ca. 140 vs. 30 nm). 4-[(4′-N,N-Diethylaminodiphenylethylene-4-ylimino)methyl]phenol (C2) and 4-[(4′-methoxyldiphenylethylene-4-ylimino)methyl]phenol (C4) display single emission bands with small Stokes shifts (ca. 30 nm) in various solvents under one- and two-photon excitation. Furthermore, the first emission maxima of C1 and C3 are almost identical to the maximum fluorescence emission wavelengths of C2 and C4, respectively. These results show that C1 and C3 can undergo ESIPT via a reasonable six-membered ring, while there is no ESIPT in C2 and C4 under one- and two-photon excitation. Compounds C1 and C2 have larger two-photon absorption cross-sections under various near-infrared laser frequencies tuned from 700 to 880 nm. Molecular geometry optimization of the phototautomers (enol and keto) was performed to analyze the experimental results. The possibility of using these chromophores for metal ions as chemosensors of was thoroughly investigated. In DMF C3 exhibits excellent sensing responses to Zn²⁺ and Fe³⁺ ions through a greatly increased greatly and a largely reduced emission, respectively. In methanol disappearance of ESIPT emission with added Zn²⁺ ions confirms its existence. The binding constants of C3 with Zn²⁺ and Fe³⁺ ions in DMF are also estimated.

Significant effects of branches and bromine substitution of near-infrared two-photon photosensitizers on the generation of singlet oxygen

Co-reporter:HongRu Li;XiaoJuan Ye;Meng Liu;Fang Gao;XiaoJiao Liu

Science Bulletin 2012 Volume 57( Issue 30) pp:3850-3854

Publication Date(Web):2012 October

DOI:10.1007/s11434-012-5388-4

This letter reports the influence of branches and bromine substitution of the photosensitizers on one- and two-photon absorption generation of singlet oxygen. Near-infrared femtosecond Ti:squassier laser was utilized to determine two-photon properties of the photosensitizers tuning wavelength from 700 to 880 nm at intervals of 20 nm. One- and two-photon optical and photophysical properties of the photosensitizers show significant dependence on the branches and substituted bromine atoms.

Synthesis and Spectroscopy of Novel Branched Fluorescent Dyes Containing Benzophenone Parts and the Possibility as Fluorescence Probes

Co-reporter:Fang Gao;Lanying Niu;Nvdan Hu;Jianchao Wang

Journal of Fluorescence 2011 Volume 21( Issue 1) pp:149-159

Publication Date(Web):2011/01/01

DOI:10.1007/s10895-010-0699-9

This paper describes a new fluorescent family of branched dyes containing benzophenone unit including 4-N, N-diphenylamino-4′-phenacyl-stilbene (C1), 4,4′-di(4-benzoylphenylethylene)yl-triphenylamine (C2) and 4,4′,4″-tri(4-benzoylphenylethylene)yl-triphenylamine (C3). Benzophenone part is coupled with core through C–C double bond. The chemical structures of the derivatives are characterized with 1H and 13C nuclear magnetic resonance and elemental analysis. Strong π–π stacking interactions are discovered with the analysis of the X-ray crystallographic data of C1. The absorption maxima and emission maxima of the derivatives exhibit gradual bathochromic shift from C1 to C3. The optical density of C1, C2 and C3 are shown to be related to the number of branches. The changes of dipole moments between the excited and ground states for C1, C2 and C3 were estimated to be 4.356, 8.091 and 8.479 Derby, respectively by Lippert equation, confirming that the internal charge transfer (ICT) dominates the process of excited singlet state. The possibility as fluorescence probes of the derivatives on the estimation of what region of micelles interacting with samples was evaluated.