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Suwannakham P, Panajapo P, Promma P, Khrootkaew T, Kamkaew A, Sagarik K. Photoluminescence mechanisms of BF 2-formazanate dye sensitizers: a theoretical study. RSC Adv 2024; 14:20081-20092. [PMID: 38915335 PMCID: PMC11195527 DOI: 10.1039/d4ra02240h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Accepted: 06/02/2024] [Indexed: 06/26/2024] Open
Abstract
Photodynamic therapy (PDT) is an alternative, minimally invasive treatment for human diseases such as cancer. PDT uses a photosensitizer to transfer photon energy directly to cellular 3O2 to generate 1O2 (Type II), the toxicity of which leads to cancer cell death. In this work, the photoluminescence mechanisms of a BF2-formazanate dye sensitizer (BF2-FORM) and its iodinated derivative (BF2-FORM-D) were studied using complementary theoretical approaches; the photoluminescence pathways in the S1 and T1 states were studied using density functional theory (DFT) and time-dependent (TD)-DFT methods, the kinetic and thermodynamic properties of the pathways using the transition state theory (TST), and the time evolution and dynamics of key processes using non-adiabatic microcanonical molecular dynamics simulations with surface-hopping dynamics (NVE-MDSH). Evaluation of the potential energy surfaces (PESs) in terms of the rotations of the phenyl rings suggested a pathway for the S1 → S0 transition for the perpendicular structure, whereas two pathways were anticipated for the T1 → S0 transition, namely, [T1 → S0]1 occurring immediately after the S1/T1 intersystem crossing (ISC) and [T1 → S0]2 occurring after the S1/T1 ISC and T1 equilibrium structure relaxation, with the T1 → S0 energy gap being comparable to the energy required for 3O2 → 1O2. The PESs also showed that because of the heavy-atom effect, BF2-FORM-D possessed a significantly smaller S1/T1 energy gap than BF2-FORM. The TST results revealed that at room temperature, BF2-FORM-D was thermodynamically more favorable than the parent molecule. Analysis of the NVE-MDSH results suggested that the librational motions of the phenyl rings play an important role in the internal conversion (IC) and ISC, and the S1/T1 ISC and T1 → S0 transitions could be enhanced by varying the irradiation wavelength and controlling the temperature. These findings can be used as guidelines to improve and/or design photosensitizers for PDT.
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Affiliation(s)
- Parichart Suwannakham
- School of Chemistry, Institute of Science, Suranaree University of Technology Nakhon Ratchasima 30000 Thailand +66 81 8783994 +66 81 8783994
| | - Pannipa Panajapo
- School of Chemistry, Institute of Science, Suranaree University of Technology Nakhon Ratchasima 30000 Thailand +66 81 8783994 +66 81 8783994
| | - Phorntep Promma
- School of Chemistry, Institute of Science, Suranaree University of Technology Nakhon Ratchasima 30000 Thailand +66 81 8783994 +66 81 8783994
| | - Tunyawat Khrootkaew
- School of Chemistry, Institute of Science, Suranaree University of Technology Nakhon Ratchasima 30000 Thailand +66 81 8783994 +66 81 8783994
| | - Anyanee Kamkaew
- School of Chemistry, Institute of Science, Suranaree University of Technology Nakhon Ratchasima 30000 Thailand +66 81 8783994 +66 81 8783994
| | - Kritsana Sagarik
- School of Chemistry, Institute of Science, Suranaree University of Technology Nakhon Ratchasima 30000 Thailand +66 81 8783994 +66 81 8783994
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El Guesmi N. Synthesis, Optical and Electrochemical Properties of Novel Formazan Analogs Incorporated Fluorene Moiety. ChemistrySelect 2023. [DOI: 10.1002/slct.202203963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Nizar El Guesmi
- Department of Chemistry Faculty of Applied Sciences Umm Al-Qura University Makkah 21955 Saudi Arabia
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Protasenko NA, Baranov EV, Yakushev IA, Bogomyakov AS, Cherkasov VK. Cobalt(III) Bis-o-semiquinone Complexes with p-Tolyl-Substituted Formazan Ligands: Synthesis, Structure, and Magnetic Properties. RUSS J COORD CHEM+ 2022. [DOI: 10.1134/s1070328422700129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Wortmann S, Kutta RJ, Nuernberger P. Monitoring the photochemistry of a formazan over 15 orders of magnitude in time. Front Chem 2022; 10:983342. [PMID: 36247663 PMCID: PMC9554553 DOI: 10.3389/fchem.2022.983342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/23/2022] [Indexed: 11/13/2022] Open
Abstract
2,3,5-triphenyltetrazolium chloride (TTC) may convert into phenyl-benzo[c]tetrazolocinnolium chloride (PTC) and 1,3,5-triphenylformazan (TPF) under irradiation with light. The latter reaction, albeit enzymatically rather than photochemically, is used in so-called TTC assays indicating cellular respiration and cell growth. In this paper, we address the photochemistry of TPF with time-resolved spectroscopy on various time scales. TPF is stabilized by an intramolecular hydrogen bond and switches photochemically via an E-Z isomerization around an N=N double bond into another TPF-stereoisomer, from which further isomerizations around the C=N double bond of the phenylhydrazone group are possible. We investigate the underlying processes by time-resolved spectroscopy in dependence on excitation wavelength and solvent environment, resolving several intermediates over a temporal range spanning 15 orders of magnitude (hundreds of femtoseconds to hundreds of seconds) along the reaction path. In a quantum-chemical analysis, we identify 16 stable ground-state isomers and discuss which ones are identified in the experimental data. We derive a detailed scheme how these species are thermally and photochemically interconnected and conclude that proton transfer processes are involved.
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Jin D, Sun X, Hinz A, Roesky PW. Rare-earth metal complexes with redox-active formazanate ligands. Dalton Trans 2022; 51:5218-5226. [PMID: 35275153 DOI: 10.1039/d2dt00456a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis and characterisation of rare-earth metal complexes with redox-active formazanate ligands are described. Deprotonation of the neutral formazan ligand L1H (L1 = PhNNC(Ph)NNPh) with [Ln{N(SiMe3)2}3] (Ln = Y, Sm, Dy) resulted in homoleptic tris(formazanate) complexes with the general formula [(L1)3Ln] (Ln = Y (1), Sm (2), Dy (3)), in which the central metal atom is coordinated by six N atoms, revealing a propeller-type structure. To generate heteroleptic complexes, a novel formazan ligand L2H (L2 = {PhNNC(4-tBuPh)NNPh}) was employed. Salt metathesis by using the trivalent precursors [SmCp*2(μ-Cl)2K(thf)] (Cp* = η5-C5Me5) or [LnCp2Cl]2 (Cp = η5-C5H5, Ln = Dy, Yb) and [L2K(thf)] formed mono(formazanate) complexes, [L2SmCp*2] (4) and [L2LnCp2] (Ln = Dy (5), Yb (6)), respectively. Unexpectedly, a redox reaction occurred between [L2K(thf)] and the divalent ytterbium precursor, [YbI2(thf)2], generating the trivalent ytterbium complex [(L2)3Yb] (7). When the neutral formazan ligand (L2H) reacted with [SmCp*2(thf)2], the oxidised samarium complex 4 was formed. These novel compounds were fully characterised and their electrochemical properties were explored by cyclic voltammetry.
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Affiliation(s)
- Da Jin
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, Geb. 30.45, 76131 Karlsruhe, Germany.
| | - Xiaofei Sun
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, Geb. 30.45, 76131 Karlsruhe, Germany.
| | - Alexander Hinz
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, Geb. 30.45, 76131 Karlsruhe, Germany.
| | - Peter W Roesky
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, Geb. 30.45, 76131 Karlsruhe, Germany.
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Singh V, Kundu A, SINGH KIRTI, Adhikari D. Redox noninnocence of formazanate ligand applied to catalytic formation of α-ketoamides. Chem Commun (Camb) 2022; 58:6630-6633. [DOI: 10.1039/d2cc02089k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The formazan ligands have been investigated as redox noninnocent backbone for a long time. Despite its well-established behaviour as redox reservoir, demonstration of catalytic efficiency governed by redox noninnocence remains...
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Near-infrared-emissive π-conjugated polymers based on five-coordinated silicon formazanate complexes. POLYMER 2022. [DOI: 10.1016/j.polymer.2021.124463] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Wortmann S, Schloeglmann S, Nuernberger P. Sensitivity of Isomerization Kinetics of 1,3,5-Triphenylformazan on Cosolvents Added to Toluene. J Org Chem 2021; 87:1745-1755. [PMID: 34843237 DOI: 10.1021/acs.joc.1c01928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Formazan molecules exhibit photochromism because isomerization processes following excitation may occur in both the azo group and the hydrazone group; thus, each formazan may be present in various forms with different colors. The ratio of these forms depends on the illumination conditions and the environment of the formazan with a most incisive sensibility of the thermal anti-syn relaxation of the C═N toward slight traces of impurities in toluene solutions, as reported most prominently for 1,3,5-triphenylformazan. Here, we study the latter compound with transient absorption spectroscopy to investigate the role of these traces by adding small amounts of both protic and aprotic cosolvents. Whereas the activation barrier decreases if the binary solvent mixture has a higher polarity, the role of hydrogen bonding can have a reverse impact on the thermal isomerization rate. Both the addition of an aprotic cosolvent and the addition of a protic cosolvent can slow the reaction due to their hydrogen-bond accepting and hydrogen-bond donating properties, respectively. In the case of methanol as a cosolvent, this effect outweighed that of the polarity increase for small concentrations, which was not observed for the fluorinated alcohol hexafluoroisopropanol. The results are explained in the context of a competition between solute-cosolvent and cosolvent-cosolvent hydrogen bonding.
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Affiliation(s)
- Svenja Wortmann
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
| | - Sylvia Schloeglmann
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
| | - Patrick Nuernberger
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
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Tikhonov SA, Sidorin AE, Samoilov IS, Borisenko AV, Vovna VI. Photoelectron spectra and electronic structure of boron diacetate formazanates. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 238:118441. [PMID: 32403076 DOI: 10.1016/j.saa.2020.118441] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 04/30/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
The electronic structure and cationic states of two 1,5-diphenylformazanes and two boron diacetate (B(OAc)2) formazanates were modeled using the outer valence Green's function (OVGF) and density functional theory (DFT) methods. Comparison of data of the OVGF and ultraviolet photoelectron spectroscopy (UPS) methods made it possible to determine an effect of functional groups and complexing agents on energies of cationic states. Addition of NO2-group at the γ-position of the chelate cycle causes stabilization of levels the five upper occupied molecular orbitals (MO) and destabilization of the bonding orbital π3Ph + π3 level. The levels of MOs π3Ph-π3 and n- are stabilized due to influence of the complexing agent B(OAc)2, with a difference in the shift of 0.67 eV. The ionization energies (In) changes for the π-orbitals of benzene rings are within the error of the OVGF method. Under methylation of phenyl groups, the differences between the calculated In, corresponding to the π-orbitals of aromatic substituents, are in good agreement with the experimental In shifts at transition from benzene to toluene. According to the OVGF method, in all the studied complexes the lowest unoccupied molecular orbital (LUMO) is localized mainly on the chelate cycle and has a strong acceptor character, which should contribute the low-lying charge-transfer electronic excitations. Moreover, an application of the DFT analog of the Koopmans' theorem with the BHHLYP and B2PLYP functionals made it possible to determine qualitatively a sequence of cationic states and energy intervals between them in the spectral range up to 10 eV. The DFT/wB97x/cc-pVTZ method data on the energy gap between the highest occupied molecular orbital (HOMO) and LUMO levels correlate with the OVGF/cc-pVTZ calculation results.
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Affiliation(s)
- Sergey A Tikhonov
- Far Eastern Federal University, School of Natural Sciences, Vladivostok 690950, Russian Federation.
| | - Andrey E Sidorin
- Far Eastern Federal University, School of Natural Sciences, Vladivostok 690950, Russian Federation
| | - Ilya S Samoilov
- Saint Petersburg State University, Department of Photonics, St. Petersburg 199034, Russian Federation
| | - Aleksandr V Borisenko
- Vladivostok Branch of Russian Customs Academy, Vladivostok 690034, Russian Federation
| | - Vitaliy I Vovna
- Far Eastern Federal University, School of Natural Sciences, Vladivostok 690950, Russian Federation
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10
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Gilroy JB, Otten E. Formazanate coordination compounds: synthesis, reactivity, and applications. Chem Soc Rev 2020; 49:85-113. [DOI: 10.1039/c9cs00676a] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Inorganic complexes of an emerging class of chelating N-donor ligands, formazanates, offer a unique combination of structurally tunable coordination modes, redox activity, and optoelectronic properties.
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Affiliation(s)
- Joe B. Gilroy
- Department of Chemistry and The Centre for Advanced Materials and Biomaterials Research (CAMBR), The University of Western Ontario
- London
- Canada
| | - Edwin Otten
- Stratingh Institute for Chemistry
- University of Groningen
- 9747 AG Groningen
- The Netherlands
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