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Lama B, Sarma M. Ultrafast Hot Exciton Nonadiabatic Excited-State Dynamics in Green Fluorescent Protein Chromophore Analogue. J Phys Chem B 2024; 128:6786-6796. [PMID: 38959128 DOI: 10.1021/acs.jpcb.4c02733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The ultrafast high-energy nonadiabatic excited-state dynamics of the benzylidenedimethylimidazolinone chromophore dimer has been investigated using an electronic structure method coupled with on-the-fly quantitative wave function analysis to gain insight into the photophysics of hot excitons in biological systems. The dynamical simulation provides a rationalization of the behavior of the exciton in a dimer after the photoabsorption of light to higher-energy states. The results suggest that hot exciton localization within the manifold of excited states is caused by the hindrance of torsional rotation due to imidazolinone (I) or phenolate (P) bonds i.e., ΦI- or ΦP-dihedral rotation, in the monomeric units of a dimer. This hindrance arises due to weak π-π stacking interaction in the dimer, resulting in an energetically uphill excited-state barrier for ΦI- and ΦP-twisted rotation, impeding the isomerization process in the chromophore. Thus, this study highlights the potential impact of the weak π-π interaction in regulating the photodynamics of the green fluorescent protein chromophore derivatives.
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Affiliation(s)
- Bittu Lama
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam 781039, India
| | - Manabendra Sarma
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam 781039, India
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Gan Q, Xu G, Deng X, Liu M, Deng Y, Lu W, Ruan Y, Fu C, Yu Y. Self-assembly solid-state enhanced fluorescence emission of GFP chromophore analogues: Formation of microsheets and microtubes oriented by molecular skeleton. J Colloid Interface Sci 2024; 654:698-708. [PMID: 37866042 DOI: 10.1016/j.jcis.2023.10.079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/05/2023] [Accepted: 10/16/2023] [Indexed: 10/24/2023]
Abstract
The p-, m- and o-N,N-dimethylamino analogs of the green fluorescent protein (GFP) chromophore (denoted as p-DBHI, m-DBHI and o-DBHI) were synthesized by 2,3-cycloaddition. These three compounds were structurally characterized by NMR, HRMS and single crystal X-ray diffraction and were shown to be in the Z-form in both the solid phase and solution. Their fluorescence properties and self-assembly behaviors were investigated by UV-Vis, photoluminescence spectroscopy, fluorescence microscopy and scanning electron microscopy. They exhibited low fluorescence quantum yields in both protic and aprotic solvents, which was consistent with the reported results, and strong emissions in the solid state, thus exhibiting aggregation-induced emission (AIE) behaviors. By a solvent exchange method, the p-DBHI and o-DBHI were assembled into microsheets, while the m-DBHI was assembled into microtubule-like structures. The photoluminescence properties of the assemblies were compared with those of the pristine microcrystalline powders obtained by evaporation from organic solvents. The fluorescence quantum yields of the microcrystals obtained by self-assembly were recorded to 9.86 %, 3.37 % and 31.65 %, respectively, which were much higher than those of the corresponding pristine powders (4.71 %, 2.51 % and 17.03 %). This indicated that the fluorescence properties in the solid state depended on the morphologies of the particles.
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Affiliation(s)
- Quan Gan
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Institute for Interdisciplinary Research, Jianghan University, Wuhan 430056, China
| | - Gongnv Xu
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Institute for Interdisciplinary Research, Jianghan University, Wuhan 430056, China
| | - Xuankai Deng
- Institute of Wuhan Studies, Jianghan University, Wuhan 430056, China
| | - Min Liu
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Institute for Interdisciplinary Research, Jianghan University, Wuhan 430056, China
| | - Yun Deng
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Institute for Interdisciplinary Research, Jianghan University, Wuhan 430056, China
| | - Wangting Lu
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Institute for Interdisciplinary Research, Jianghan University, Wuhan 430056, China
| | - Yibin Ruan
- Technology Center of China Tobacco Guizhou Industrial Co. Ltd., Guiyang 550003, China
| | - Cheng Fu
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Institute for Interdisciplinary Research, Jianghan University, Wuhan 430056, China.
| | - Yanhua Yu
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Institute for Interdisciplinary Research, Jianghan University, Wuhan 430056, China.
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Ke HW, Sung K. 7-membered-ring effect on fluorescence quantum yield: does metal-complexation-induced twisting-inhibition of an amino GFP chromophore derivative enhance fluorescence? Phys Chem Chem Phys 2023; 25:14627-14634. [PMID: 37194347 DOI: 10.1039/d3cp00467h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
To investigate two aspects, namely, (1) the 7-membered-ring effect on fluorescence quantum yield and (2) whether metal-complexation-induced twisting-inhibition of an amino green fluorescent protein (GFP) chromophore derivative is bound to enhance fluorescence, a novel GFP-chromophore-based triamine ligand, (Z)-o-PABDI, is designed and synthesized. Before complexation with metal ions, the S1 excited state of (Z)-o-PABDI undergoes τ-torsion relaxation (Z/E photoisomerization) with a Z/E photoisomerization quantum yield of 0.28, forming both ground-state (Z)- and (E)-o-PABDI isomers. Since (E)-o-PABDI is less stable than (Z)-o-PABDI, it is thermo-isomerized back to (Z)-o-PABDI at room temperature in acetonitrile with a first-order rate constant of (1.366 ± 0.082) × 10-6 s-1. After complexation with a Zn2+ ion, (Z)-o-PABDI as a tridentate ligand forms a 1 : 1 complex with the Zn2+ ion in acetonitrile and in the solid state, resulting in complete inhibition of the φ-torsion and τ-torsion relaxations, which does not enhance fluorescence but causes fluorescence quenching. (Z)-o-PABDI also forms complexes with other first-row transition metal ions Mn2+, Fe3+, Co2+, Ni2+ and Cu2+, generating almost the same fluorescence quenching effect. By comparison with the 2/Zn2+ complex, in which a 6-membered ring of Zn2+-complexation enhances fluorescence significantly (a positive 6-membered-ring effect on fluorescence quantum yield), we find that the flexible 7-membered rings of the (Z)-o-PABDI/Mn+ complexes trigger their S1 excited states to relax through internal conversion at a rate much faster than fluorescence (a negative 7-membered-ring effect on fluorescence quantum yield), leading to fluorescence quenching regardless of the type of transition metal that complexes with (Z)-o-PABDI.
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Affiliation(s)
- Hao-Wei Ke
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
| | - Kuangsen Sung
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
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Lama B, Sarma M. Unraveling the Mechanistic Pathway for the Dual Fluorescence in Green Fluorescent Protein (GFP) Chromophore Analogue: A Detailed Theoretical Investigation. J Phys Chem B 2022; 126:9930-9944. [PMID: 36354358 DOI: 10.1021/acs.jpcb.2c03842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The photophysical properties of the para-sulfonamide (p-TsABDI) analogue of the green fluorescent protein (GFP) chromophore with both proton donating and accepting sites have been exploited in polar solvents to understand the origin of the unusual dual fluorescence nature of the chromophore. In the polar solvents, the compound undergoes structural rearrangement upon photoexcitation, leading to the ultrafast excited-state intermolecular proton transfer (ESIPT) phenomenon at the S1 surface. In this work, we employed both the static electronic structure calculations and on-the-fly molecular dynamics simulation to unravel the underlying reason for this peculiar behavior of the p-TsABDI analogue in polar solvents. To represent this adequately and provide extensive information on the ESIPT mechanism mediated by the solvent molecules, we considered explicit solvent molecules using the integral equation formalism variant of polarizable continuum (IEFPCM) model. From the static calculation analysis, we can conclude that the dual emissive behavior of the compound is ascribed to the proton transfer (PT) phenomena in the excited-state. However, based on the static calculation exclusively, it is hard to ascertain the mechanistic pathway of the PT phenomena. Hence, to investigate the dynamics and reaction mechanism for the ESIPT process, we performed the on-the-fly dynamics simulation for p-TsABDI in solvent clusters. Dynamics simulation results reveal that, based on the time lag between all the proton transfer processes, the ESIPT mechanism occurs in a stepwise manner from the benzylidene moiety of the chromophore to its imidazolinone moiety. However, the nonexistence of crossings between the S1- and S0-states confirms the PT characteristics of the reactions.
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Affiliation(s)
- Bittu Lama
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam781039, India
| | - Manabendra Sarma
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam781039, India
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Liao JW, Sung R, Sung K. Against the NEER principle: the third type of photochromism for GFP chromophore derivatives. Phys Chem Chem Phys 2021; 24:295-304. [PMID: 34889318 DOI: 10.1039/d1cp03581a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photochromism is the heart of photochromic fluorescent proteins. Excited-state proton transfer (ESPT) is the major cause of photochromism for the green fluorescent protein (GFP) and Z-E photoisomerization through τ-torsion is the major cause of photochromism for Dronpa (a GFP mutant). In this article, s-E-1 opens a third type of photochromism for GFP chromophore derivatives, which involves light-driven φ-torsion with no τ-torsion, followed by excited-state intramolecular proton transfer (ESIPT), and is gated by environmental polarity. Since s-E-1 does not follow Z-E photoisomerization through τ-torsion but undergoes light-driven φ-torsion, which involves equilibration of the excited-state rotamers, it is clearly against the NEER (Non-Equilibration of Excited-state Rotamers) principle.
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Affiliation(s)
- Jun-Wei Liao
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
| | - Robert Sung
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
| | - Kuangsen Sung
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
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Liu X, Zhou Z, Wang T, Deng P, Yan Y. Visual monitoring of trace water in organic solvents based on ecofriendly b/r-CDs ratiometric fluorescence test paper. Talanta 2020; 216:120958. [PMID: 32456929 DOI: 10.1016/j.talanta.2020.120958] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 11/16/2022]
Abstract
Developing a green, non-toxic and easy to synthesize of fluorescence probe for fast and visual detecting trace water in various organic solvents was an important task. Here, a novel dual-emission fluorescence probe (b/r-CDs) was designed based on the red CDs (r-CDs) and blue CDs (b-CDs) to detect the trace water and enhance the visualization for naked-eye observation in different organic solvents. Among, the red fluorescence carbon dots (CDs) was found to have the capability to monitor trace amounts of water, which synthesized with green tea by facile ultrasonic method. Further, Such a dual-emission probe could fast monitor trace water in various organic solvents with high stability and fast response. Importantly, a synergistic mechanism of the dynamic process (b-CDs) and static quenching (r-CDs) was proved for the study of water detection. Moreover, the test paper was made for detecting trace water in different organic solvents, achieving convenient and effective detection.
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Affiliation(s)
- Xiqing Liu
- School of Material Science and Engineering, Jiangsu University, 212013, Zhenjiang, PR China
| | - Zhiping Zhou
- School of Material Science and Engineering, Jiangsu University, 212013, Zhenjiang, PR China
| | - Tao Wang
- School of Chemistry and Chemical Engineering, Jiangsu University, 212013, Zhenjiang, PR China
| | - Pengyin Deng
- College of Chemistry, Jilin Normal University, 13600, Siping, PR China
| | - Yongsheng Yan
- School of Material Science and Engineering, Jiangsu University, 212013, Zhenjiang, PR China; Institute of Green Chemistry and Chemical Technology, Jiangsu University, 212013, Zhenjiang, PR China.
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Chen YH, Sung R, Sung K. Dramatic changes in the excited-state behaviour of the green fluorescent protein chromophore by a strong π-donating group through significantly lowering the excited-state potential energy surface with photoinduced intramolecular charge transfer. Phys Chem Chem Phys 2020; 22:2424-2428. [PMID: 31939956 DOI: 10.1039/c9cp06231a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A strong π-donating group like p-NMe2 dramatically changes the excited-state behavior of the green fluorescent protein (GFP) chromophore, such as realizing charge-transfer absorption and executing significant photoinduced intramolecular charge transfer (ICT), which makes a planar first singlet (S1) excited-state minimum disappear and significantly lowers the S1 excited-state potential energy surface (PES), leading to barrierless τ-torsion and φ-torsion excited-state relaxation and eliciting the φ-torsion S1 excited-state minimum. This finding is critical since a strong π-donating group like p-NMe2 may do the same things to other fluorophores.
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Affiliation(s)
- Yi-Hui Chen
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, Republic of China.
| | - Robert Sung
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, Republic of China.
| | - Kuangsen Sung
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, Republic of China.
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