- A lysosome-targeted ruthenium(II) polypyridyl complex as photodynamic anticancer agent
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Polypyridyl ruthenium complexes as novel photosensitizers had drawn attention due to its high selectivity towards cancer cells and low toxicity to normal cells. Herein, we synthesized a lysosome-targeted polypyridyl ruthenium complex Rhein-Ru(bpy)3 (bpy = 2,2′-bipyridine, rhein = 4,5-dihydroxy-9,10-dioxoanthracene-2-carboxylic acid), tethering with the Chinese medicine herb rhein. Rhein-Ru(bpy)3 exhibited high phototoxicity with short time of irradiation against tumor cell lines with the IC50 value of 2.4– 8.7 μM, and higher cytotoxicity against cisplatin-resistant A2780 cell lines, suggesting that Rhein-Ru(bpy)3 could overcome the cisplatin resistance. Moreover, Rhein-Ru(bpy)3 displayed low cytotoxicity towards cell lines in dark incubation, which was beneficial to reduce the toxic side effects towards normal cell lines. Besides, the confocal imaging and western blotting assay results suggested that Rhein-Ru(bpy)3 could induce cancer cell death through the autophagy pathway. These results inspired us that lysosome-targeted photosensitizers based on ruthenium complexes showed great potential for photodynamic therapy (PDT) application in cancer treatment.
- Chen, Jun,Liu, Hong-Ke,Qian, Yong,Su, Zhi,Tao, Qin,Wang, Mengmeng,Wang, Yan,Wu, Jian,Xue, Xuling,Yu, Tao
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- Light-Activated Electron Transfer and Turnover in Ru-Modified Aldehyde Deformylating Oxygenases
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Conversion of biological molecules into fuels or other useful chemicals is an ongoing chemical challenge. One class of enzymes that has received attention for such applications is aldehyde deformylating oxygenase (ADO) enzymes. These enzymes convert aliphatic aldehydes to the alkanes and formate. In this work, we prepared and investigated ADO enzymes modified with RuII(tris-diimine) photosensitizers as a starting point for probing intramolecular electron transfer events. Three variants were prepared, with RuII-modification at the wild type (WT) residue C70, at the R62C site in one mutant ADO, and at both C62 and C70 in a second mutant ADO protein. The single-site modification of WT ADO at C70 using a cysteine-reactive label is an important observation and opens a way forward for new studies of electron flow, mechanism, and redox catalysis in ADO. These Ru-ADO constructs can perform the ADO catalytic cycle in the presence of light and a sacrificial reductant. In this work, the Ru photosensitizer serves as a tethered, artificial reductase that promotes turnover of aldehyde substrates with different carbon chain lengths. Peroxide side products were detected for shorter chain aldehydes, concomitant with less productive turnover. Analysis using semiclassical electron transfer theory supports proposals for hopping pathway for electron flow in WT ADO and in our new Ru-ADO proteins.
- Bains, Rajneesh K.,Miller, Jessica J.,Van Der Roest, Hannah K.,Qu, Sheng,Lute, Brad,Warren, Jeffrey J.
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- Multinuclear ruthenium(II) complexes as anticancer agents
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A series of dinuclear ruthenium(ii) complexes that contain labile chlorido ligands, [{Ru(tpy)Cl}2{μ-bbn}]2+ {designated Cl-Rubbn; tpy = 2,2′:6′,2′′-terpyridine, bbn = bis[4(4′-methyl-2,2′-bipyridyl)]-1,n-alkane (n = 7, 10, 12, 14 or 16)} and derivatives containing nitro substituents on the tpy ligand and/or secondary amines within the bbn linking chain have been synthesised and their potential as anticancer agents examined. Some of the Cl-Rubbn species showed good anticancer activity against MCF-7 and MDA-MB-231 breast cancer cell lines, with the Cl-Rubb12 complex being four-times more active than cisplatin. Inclusion of nitro substituents on the tpy ligands of Cl-Rubb12 resulted in significantly decreased anticancer activity. The incorporation of amine groups into the linking ligand did not increase the anticancer activity of the Cl-Rubbn complexes. The Cl-Rubbn complexes and those containing amine groups in the linking chain aquated at approximately the same rate, with 50% aquation within 120 minutes. By comparison, the complexes containing nitro substituents on the tpy ligand aquated extremely slowly, with 60% of the chlorido complex remaining 24 hours after they were dissolved in water. Cyclic voltammetry with the model mononuclear complex [Ru{(NO2)3tpy}(Me2bpy)Cl] + {(NO2)3tpy = 4,4′,4′′- trinitro-2,2′:6′,2′′-terpyridine} showed that the nitro substituents exerted a strong effect on the ruthenium centre, with the anodic peak corresponding to the Ru(iii/ii) couple shifted positively by 300 mV compared to that from the non-nitrated parent complex [Ru(tpy)(Me 2bpy)Cl]+. 1H NMR studies of the reaction of the Cl-Rubbn complexes with GMP indicated that the ruthenium complexes covalently bound the nucleotide slowly, with 33% bound in 24 hours. However, the results of this study suggest that the cytotoxicity of the dinuclear ruthenium complexes is a combination of covalent and reversible binding with DNA. the Partner Organisations 2014.
- Gorle, Anil K.,Ammit, Alaina J.,Wallace, Lynne,Keene, F. Richard,Collins, J. Grant
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- Low-Energy and Long-Lived Emission from Polypyridyl Ruthenium(II) Complexes Having A Stable-Radical Substituent
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Novel polypyridyl ruthenium(II) complexes having a 2,2′-bipyridine (bpy) derivative which possesses a 1,5-dimethyl-6-oxoverdazyl radical (OV) group as a stable-radical substituent were designed and synthesized. The radical-ruthenium(II) complexes showed low-energy/intense MLCT absorption and low-energy/long-lived MLCT emission, and these characteristics of the complexes were explained by the electron-withdrawing nature of the OV group. Furthermore, the radical-substituent effects were enhanced by the presence of the electron-donating methyl groups at the 4- and 4′-positions of bpy in the ancillary ligands. The detailed electrochemical, spectroscopic, and photophysical properties of the complexes were discussed in terms of the systematic modification of the second coordination sphere in the main and ancillary ligands.
- Ito, Akitaka,Kobayashi, Nozomi,Teki, Yoshio
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- Molecular recognition and reactivity of ruthenium(II) bipyridine barbituric acid guests in the presence of complementary hosts: Ruthenium(II) promoted enolization of barbituric acids in guest-host complexes
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The binding of the host H1 (N,N'-bis(6-pivalamidopyrid-2-yl)-3,5- pyridinedicarboxamide) to three different ruthenium polypyridine complexes with an attached barbituric acid and barbital moieties (RuG1, RuG2, RuG3) (where G1 = 5-[4-(4'-methyl)-2,2'-bipyridylidene]-2,4,6-(1H,3H,5H)- pyrimidinetrione, G2 = 5-[4-(4'-methyl)-2,2'-bipyridyl]methyl-2,4,6- (1H,3H,5H)-pyrimidinetrione, and G3 = 5-ethyl, 5-[4-(4'-methyl)-2,2'- bipyridyl]methyl-2,4,6-(1H,3H,5H)-pyrimidinetrione) and Ru = (4,4'-di-tert- butyl-bpy)2Ru (bpy = 2,2'-bipyridine) has been studied in chlorinated solvents by NMR and fluorescence titrations. Significant binding was only observed between H1 and the RuG2 series, while steric hindrance significantly diminished binding between H1 and RuG1 or RUG3. The high binding constant for RuG2 was related to the presence of the enolate form of the barbituric acid guest which forms strong H-bonds with the complementary host H1. For the organic barbituric acid and barbital guests, the keto and enol bind only weakly to H1 (K ~ 102 M-1); binding is further increased in the presence of base to generate the enolate. In contrast, formation of the RuG2 enolate occurs upon binding to H1 without any additional base. The ruthenium polypyridine cation (compared to the organic barbituric acid derivatives) facilitates ionization of the enol to enolate thus producing a better complementary H-bonding site between the guest and host. Molecular mechanics calculations confirmed the experimental observations that the enolate has the highest binding constant to the Host H1, while the corresponding enol form has the weakest binding.
- Chin, Teen,Gao, Zhinong,Lelouche, Isabelle,Shin, Yeung-Gyo K.,Purandare, Ashok,Knapp, Spencer,Isied, Stephan S.
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- Super-Resolution Tracking of Mitochondrial Dynamics with An Iridium(III) Luminophore
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Combining luminescent transition metal complex with super-resolution microscopy is an excellent strategy for the long-term visualization of the dynamics of subcellular structures in living cells. However, it remains unclear whether iridium(III) complexes are applicable for a particular type of super-resolution technique, structured illumination microscopy (SIM), to image subcellular structures. Herein, an iridium(III) dye, to track mitochondrial dynamics in living cells under SIM is described. The dye demonstrates excellent specificity and photostability and satisfactory cell permeability. While using SIM to image mitochondria, an ≈80 nm resolution is achieved that allows the clear observation of the structure of mitochondrial cristae. The dye is used to monitor and quantify mitochondrial dynamics relative to lysosomes, including fusion involved in mitophagy, and newly discovered mitochondria–lysosome contact (MLC) under different conditions. The MLC remains intact and fusion vanishes when five receptors, p62, NDP52, OPTN, NBR1, and TAX1BP1, are knocked out, suggesting that these two processes are independent.
- Chen, Qixin,Jin, Chengzhi,Shao, Xintian,Guan, Ruilin,Tian, Zhiqi,Wang, Chenran,Liu, Fei,Ling, Peixue,Guan, Jun-Lin,Ji, Liangnian,Wang, Fengshan,Chao, Hui,Diao, Jiajie
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- Atom transfer radical polymerization preparation and photophysical properties of polypyridylruthenium derivatized polystyrenes
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A ruthenium containing polymer featuring a short carbonyl-amino-methylene linker has been prepared by atom transfer radical polymerization (ATRP). The polymer was derived from ATRP of the N-hydroxysuccinimide (NHS) derivative of p-vinylbenzoic acid, followed by an amide coupling reaction of the NHS-polystyrene with Ru(II) complexes derivatized with aminomethyl groups (i.e., [Ru(bpy)2(CH3-bpy-CH2NH2)] 2+ where bpy is 2,2′-bipyridine, and CH3-bpy-CH 2NH2 is 4-methyl-4′-aminomethyl-2,2′- bipyridine). The Ru-functionalized polymer structure was confirmed by using nuclear magnetic resonance and infrared spectroscopy, and the results suggest that a high loading ratio of polypyridylruthenium chromophores on the polystyrene backbone was achieved. The photophysical properties of the polymer were characterized in solution and in rigid ethylene glycol glasses. In solution, emission quantum yield and lifetime studies reveal that the polymer's metal-to-ligand charge transfer (MLCT) excited states are quenched relative to a model Ru complex chromophore. In rigid media, the MLCT-ground state band gap and lifetime are both increased relative to solution with time-resolved emission measurements revealing fast energy transfer hopping within the polymer. Molecular dynamics studies of the polymer synthesized here as well as similar model systems with various spatial arrangements of the pendant Ru complex chromophores suggest that the carbonyl-amino-methylene linker probed in our target polymer provides shorter Ru-Ru nearest-neighbor distances leading to an increased Ru*-Ru energy hopping rate, compared to those with longer linkers in counterpart polymers.
- Fang, Zhen,Ito, Akitaka,Keinan, Shahar,Chen, Zuofeng,Watson, Zoe,Rochette, Jason,Kanai, Yosuke,Taylor, Darlene,Schanze, Kirk S.,Meyer, Thomas J.
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- Stabilising the lowest energy charge-separated state in a {metal chromophore-fullerene} assembly: A tuneable panchromatic absorbing donor-acceptor triad
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Photoreduction of fullerene and the consequent stabilisation of a charge-separated state in a donor-acceptor assembly have been achieved, overcoming the common problem of a fullerene-based triplet state being an energy sink that prevents charge-separation. A route to incorporate a C60-fullerene electron acceptor moiety into a catecholate-Pt(ii)-diimine photoactive dyad, which contains an unusually strong electron donor, 3,5-di-tert-butylcatecholate, has been developed. The synthetic methodology is based on the formation of the aldehyde functionalised bipyridine-Pt(ii)-3,5-di-tert-butylcatechol dyad which is then added to the fullerene cage via a Prato cycloaddition reaction. The resultant product is the first example of a fullerene-diimine-Pt-catecholate donor-acceptor triad, C60bpy-Pt-cat. The triad exhibits an intense solvatochromic absorption band in the visible region due to catechol-to-diimine charge-transfer, which, together with fullerene-based transitions, provides efficient and tuneable light harvesting of the majority of the UV/visible spectral range. Cyclic voltammetry, EPR and UV/vis/IR spectroelectrochemistry reveal redox behaviour with a wealth of reversible reduction and oxidation processes forming multiply charged species and storing multiple redox equivalents. Ultrafast transient absorption and time resolved infrared spectroscopy, supported by molecular modelling, reveal the formation of a charge-separated state [C60-bpy-Pt-cat+] with a lifetime of ～890 ps. The formation of cat+ in the excited state is evidenced directly by characteristic absorption bands in the 400-500 nm region, while the formation of C60- was confirmed directly by time-resolved infrared spectroscopy, TRIR. An IR-spectroelectrochemical study of the mono-reduced building block (C60-bpy)PtCl2, revealed a characteristic C60- vibrational feature at 1530 cm-1, which was also detected in the TRIR spectra. This combination of experiments offers the first direct IR-identification of C60- species in solution, and paves the way towards the application of transient infrared spectroscopy to the study of light-induced charge-separation in C60-containing assemblies, as well as fullerene films and fullerene/polymer blends in various OPV devices. Identification of the unique vibrational signature of a C60-anion provides a new way to follow photoinduced processes in fullerene-containing assemblies by means of time-resolved vibrational spectroscopy, as demonstrated for the fullerene-transition metal chromophore assembly with the lowest energy charge-separated excited state.
- Lebedeva, Maria A.,Chamberlain, Thomas W.,Scattergood, Paul A.,Delor, Milan,Sazanovich, Igor V.,Davies, E. Stephen,Suyetin, Mikhail,Besley, Elena,Schr?der, Martin,Weinstein, Julia A.,Khlobystov, Andrei N.
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- Telechelic poly(ε-caprolactones) with tethered mixed ligand ruthenium(II) chromophores
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Well-characterized templates of polymer-forming ligands and their ruthenium tris(αα′-diimine) initiators were utilized to divergently ring open an ε-caprolactone monomer. The same polymers were also obtained through the synthesis of quinoline and bipyridine diimine ligands incorporating poly(ε-caprolactone) (PCL) chains. These polymers contain vacant molecular recognition sites, enabling subsequent chelation of these macroligands to metal precursors. Both methods provided telechelic (ε-caprolactone) ruthenium(II)-centered polyesters of various hierarchy. Solution properties and thermal behaviour of such polyesters are described.
- Farah, Abdiaziz A.,Pietro, William J.
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- Cyclometalated Iridium(III) Bipyridine–Phenylboronic Acid Complexes as Bioimaging Reagents and Luminescent Probes for Sialic Acids
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Sialic acids play important roles in mammalian development, cell–cell attachment, and signaling. As cancer cells utilize their overexpressed sialylated antigens to propagate metastases, the development of probes for sialic acids is of high importance. Herein, we report three luminescent cyclometalated iridium(III) bipyridine complexes bearing a phenylboronic acid (PBA) moiety. Spectrophotometric titrations revealed that the PBA complexes displayed higher binding affinity for the most common sialic acid N-acetylneuraminic acid (Neu5Ac) compared with simple sugars that are commonly found on glycoproteins. Notably, cellular imaging and uptake experiments showed that the PBA complexes were able to recognize cellular sialic acid residues, resulting in more efficient uptake than the boronic acid-free analogs. Additionally, one of the PBA complexes was shown to discriminate between cancerous and noncancerous cells.
- Liu, Hua-Wei,Law, Wendell Ho-Tin,Lee, Lawrence Cho-Cheung,Lau, Jonathan Chun-Wai,Lo, Kenneth Kam-Wing
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- Highly efficient and selective photocatalytic oxidation of sulfide by a chromophore-catalyst dyad of ruthenium-based complexes
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Electronic coupling across a bridging ligand between a chromophore and a catalyst center has an important influence on biological and synthetic photocatalytic processes. Structural and associated electronic modifications of ligands may improve the efficiency of photocatalytic transformations of organic substrates. Two ruthenium-based supramolecular assemblies based on a chromophore-catalyst dyad containing a Ru-aqua complex and its chloro form as the catalytic components were synthesized and structurally characterized, and their spectroscopic and electrochemical properties were investigated. Under visible light irradiation and in the presence of [Co(NH3)5Cl]Cl2 as a sacrificial electron acceptor, both complexes exhibited good photocatalytic activity toward oxidation of sulfide into the corresponding sulfoxide with high efficiency and >99% product selectivity in neutral aqueous solution. The Ru-aqua complex assembly was more efficient than the chloro complex. Isotopic labeling experiments using 18O-labeled water demonstrated the oxygen atom transfer from the water to the organic substrate, likely through the formation of an active intermediate, Ru(IV)=O.
- Li, Ting-Ting,Li, Fu-Min,Zhao, Wei-Liang,Tian, Yong-Hua,Chen, Yong,Cai, Rong,Fu, Wen-Fu
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- Synthesis of C3-cyclotriveratrylene ligands for iron(II) and iron(III) coordination
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The design and synthesis of a new family of siderophores based on cyclotriveratrylene is described. The ligands consist of a C3-cyclotriveratrylene unit provided with three arms (spacers) ending with hydroxamate, catecholate, bipyridine, or iminopyridine units suitable for the octahedral coordination of transition metals and particularly for the complexation of iron(II) and iron(III).
- Veriot, Gilles,Dutasta, Jean-Pierre,Matouzenko, Galina,Collet, Andre
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- Synthesis and Luminescence Properties of Di- and Tri-methylene Linked Tris(2,2'-bipyridine)ruthenium(II) Complex Dimers. Ground-Excited State Interaction
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Di- and tri-methylene-linked Ru(bpy)3(2+) complexes 2 were synthesized.The luminescence properties of 2 were compared with those of its component monomer.In the excited 2 systems, the intermolecular interaction leading to the enhanced quenching or the formation of a new triplet excimer was not observed.
- Furue, Masaoki,Kuroda, Noritaka,Nozakura, Shun-ichi
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- A CN- specific turn-on phosphorescent probe with probable application for enzymatic assay and as an imaging reagent
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A new "turn-on" luminescence probe for imaging the uptake of 0.2 ppm inorganic CN- in live HeLa cells as well as for probing the CN- generation through an enzymatic process in a virtual aqueous medium at appropriate pH. This journal is
- Reddy G., Upendar,Das, Priyadip,Saha, Sukdeb,Baidya, Mithu,Ghosh, Sudip K.,Das, Amitava
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- Bipyridine carbaldehydes as electrophiles in the Morita-Baylis-Hillman reaction: synthesis of highly functionalized bipyridyl ligands and a macrocycle
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A simple and efficient Morita-Baylis-Hillman (MBH) reaction of bipyridine carbaldehydes and unexplored activated alkenes afforded highly functionalized bipyridyl ligands. Particularly, one-pot MBH reaction of 2,2′-bipyridine-4,4′-dicarbaldehyde and 2,2′-bipyridine-4-methyl-4′-carbaldehyde with 1,6-hexanediol diacrylate afforded a twenty membered bipyridyl macrocycle and bis MBH adducts, respectively. Synthetic transformations of mono and bis MBH adducts thus obtained have been demonstrated by preparing bipyridyl N-oxide and [3+2]-cycloadduct of azomethine ylide derived from isatin and proline.
- Gouthaman, Siddan,Periyaraja, Somasundharam,Shanmugam, Ponnusamy
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- Functionalization of 2,2'-bipyridines in their 4 and 5 positions. Synthesis of 5-Ethynyl-2,2'-Bipyridine
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The synthesis of 5-ethynyl-2,2'-bipyridine (9) from 5methyl-2.2'- bipyridine (5) is reported. The conversion of the methyl derivative, which is the most common starting material to further substitution, involves the preparation of 2,2'-bipyridine-5-carbaldehyde (6). Corey-Fuchs olefination and subsequent hydrolysis yields the target compound 9. The multistep synthesis is discussed with respect to alternative routes and compared with those of related 4-substituted 2,2'-bipyridines.
- Polin, Johann,Schmohel, Erich,Balzani, Vincenzo
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- Synthesis, photophysical properties and spectroelectrochemical characterization of 10-(4-methyl-bipyridyl)-5,15-(pentafluorophenyl)corrole
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The new bipyridyl-corrole dye 10-(4-methyl-bipyridyl)-5,15-(pentafluorophenyl)corrole, encompassing a coordenative methyl-bipyridine moiety (corrole 2), was prepared starting from 5-(pentafluorophenyl)dipyrromethane and reacting it with methyl-bipyridyl-carboxaldehyde by Grykós methodology. It was further characterized by spectroscopic and electrochemical methods. In addition, we investigated experimental photophysical properties, photostability, reactive oxygen species generation (ROS) and aggregation phenomena, which are relevant when selecting photosensitizers used in photodynamic therapy and many other applications. Photophysical properties have demonstrated that the corrole 2 dissolved in dichloromethane has a triplet quantum yield formation of about 51%. Fluorescence and internal conversion quantum yields of 4% and 45%, respectively, have also been determined in order to evaluate which could be was the main pathway of the excited state relaxation. Triplet state formation was also confirmed by measuring indirectly 1O2 generation. Additionally, quantum chemistry calculations indicated that the most probable intersystem-crossing pathway takes place through S1-T1, corroborating our rate equation model.
- Pivetta, Rhannanda C.,Auras, Bruna L.,Souza, Bernardo de,Neves, Ademir,Nunes, Fábio S.,Cocca, Leandro H.Z.,Boni, Leonardo De,Iglesias, Bernardo A.
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- Covalent bonding photosensitizer–catalyst dyads of ruthenium-based complexes designed for enhanced visible-light-driven water oxidation performance
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Abstract: We have successfully prepared two ruthenium-based covalent bonding photosensitizer–catalyst dyads through a simple procedure. 1H NMR spectra of both dyads show that only a single stereoisomer was formed for each dyad. The spectroscopic and electrochemical properties and photocatalytic water oxidation activities of both dyads were investigated in detail. The results indicate that there is negligible electron communication between the photosensitizer and catalyst centers, and each component maintains the desired photophysical and electrochemical properties, which would diminish excited-state electron recombination by facilitating the intramolecular electron transfer. In the presence of excess sacrificial electron acceptor, the dyad with iodide ligand shows a 5.5-fold increase in catalytic performance as compared to its chloro analogue, indicating that the iodide ligand plays an important role during the catalytic cycle. Moreover, compared with the multi-component system, the dyad with iodide ligand exhibits a fourfold increase in catalytic turnover number. Graphical abstract: [Figure not available: see fulltext.].
- Chen, Qihang,Zhou, Qianqian,Li, Ting-Ting,Liu, Runze,Li, Hongwei,Guo, Fenya,Zheng, Yue-Qing
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- Electron transfer from photoexcited naphthalene-1,4:5,8-bis(dicarboximide) radical anion to Mn(bpy)(CO)3X and Re(bpy)(CO)3X CO2 reduction catalysts linked via a saturated methylene bridge
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Supramolecular systems that connect a naphthalene-1,4:5,8-bis(dicarboximide) (NDI) radical anion donor to Mn(bpy)(CO)3Br or Re(bpy)(CO)3Cl CO2 reduction catalysts via a methylene bridge have been synthesized and studied by femtosecond transient visible, near-infrared and mid-infrared spectroscopy. The use of the methylene bridge to link NDI to the complexes does not affect the reduction potentials of the metal complexes. Selective photoexcitation of NDI?? to 2*NDI?? results in ultrafast reduction of the bipyridine (bpy) ligands on both the Mn and Re complexes to form Mn(I)(bpy??)(CO)3X and Re(I)(bpy??)(CO)3X in near unity quantum yield, respectively. The initial formation of Mn(I)(bpy??)(CO)3X is unexpected based on previous electrochemical data that indicates the Mn(I) center is reduced at a more positive potential than the bpy ligand. Moreover, the rate of forward electron transfer in the Mn complex was found to be faster than in the Re complex, while the rate of the back electron transfer in the Re complex was faster than in the Mn complex.
- Martinez, Jose F.,La Porte, Nathan T.,Wasielewski, Michael R.
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- Iridium motif linked porphyrins for efficient light-driven hydrogen evolution via triplet state stabilization of porphyrin
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Two new iridium motif linked porphyrins, MBPyZnP-Ir and TBPyZnP-Ir are developed for photocatalytic hydrogen evolution (PHE). The tetra-iridium linked one, TBPyZnP-Ir, displayed the highest H2 production rate (ηH2) of 16.12 mmol g-1 h-1 within 5 h of irradiation, which is over 2.73-fold higher than MBPyZnP-Ir (5.90 mmol g-1 h-1) and much higher than their precursors TBPyZnP (0.12 mmol g-1 h-1) and MBPyZnP (0.06 mmol g-1 h-1) without iridium. The superior ηH2 of TBPyZnP-Ir could be explained by the iridium motifs linked to the porphyrin, stabilizing the triplet states of the porphyrin through intramolecular energy transfer; thus enhancing electron transfer from the triplet photo-excited porphyrin moiety to the cobaloxime co-catalyst and consequently proton reduction.
- Bodedla, Govardhana Babu,Kwan, Chak-Shing,Leung, Ken Cham-Fai,Tang, Geliang,Tritton, Daniel Nnaemaka,Wong, Wai-Yeung,Zhao, Jianzhang,Zhu, Xunjin
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- Bioorthogonal oxime ligation of a Mo(CO)4(N-N) CO-releasing molecule (CORM) to a TGF β-binding peptide
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Carbon monoxide is now well-established as an endogenously produced gasotransmitter in humans. To utilizes its spectrum of biological activity for therapeutic purposes, solid storage forms such as metal carbonyl complexes have to be used for easy handling and targeted delivery to the body. Thus, in the present work, a [Mo(CO)4(bpyCH3,CHO)] complex with an aldehyde group in a peripheral position on the 2,2′-bipyridine (bpy) ligand was coupled to a bioactive transforming growth factor (TGF) β-targeting peptide N-terminally functionalized with aminoxy acetic acid using the bioorthogonal and catalyst-free oxime ligation. CO release studies with the myoglobin assay as well as UV/Vis and IR spectroscopy showed the molybdenum tetracarbonyl moiety to slowly liberate carbon monoxide upon incubation in buffer in the dark. In addition, photoactivation at 468 nm with a LED array resulted in a significantly accelerated release of carbon monoxide, thus establishing this peptide bioconjugate as a new photoactivatable CO-releasing molecule (PhotoCORM) with a red-shifted excitation wavelength for better tissue penetration.
- Pfeiffer, Hendrik,Sowik, Thomas,Schatzschneider, Ulrich
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- Proton-Coupled Electron-Transfer Processes in Ultrafast Time Domain: Evidence for Effects of Hydrogen-Bond Stabilization on Photoinduced Electron Transfer
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The proton-coupled electron-transfer (PCET) reaction is investigated for a newly synthesized imidazole-anthraquinone biomimetic model with a photoactive RuII-polypyridyl moiety that is covalently coupled to the imidazole fragment. Intramolecular H-bonding interactions between imidazole and anthraquinone moieties favor the PCET process; this can be correlated to an appreciable positive shift in the one-electron reduction potential of the coordinated anthraquinone moiety functionalized with the imidazole fragment. This can also be attributed to the low luminescence quantum yield of the RuII-polypyridyl complex used. The dynamics of the intramolecular electron-transfer (ET) and PCET processes are studied by using femtosecond transient absorption spectroscopy. The steady-state spectroscopic studies and the results of the time-resolved absorption studies confirm that H-bonded water molecules play a major role in both ET and PCET dynamics as a proton relay in the excited state. The electron-transfer process is followed by a change in the H-bonding equilibrium between AQ and imidazole in acetonitrile solvent, and protonation of AQ.? by water leads to PCET in the presence of water. A slower forward and backward electron-transfer rate is observed in the presence of D2O compared with that in H2O. These results provide further experimental support for a detailed understanding of the PCET process.
- Dey, Ananta,Dana, Jayanta,Aute, Sunil,Maity, Partha,Das, Amitava,Ghosh, Hirendra N.
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- Iron(iii)-bipyridine incorporated metal-organic frameworks for photocatalytic reduction of CO2with improved performance
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Metal-organic frameworks (MOFs) represent an emerging class of platforms to assemble single site photocatalysts for artificial photosynthesis. In this work, we report a new CO2 reduction photocatalyst (UiO-68-Fe-bpy) based on a robust Zr(iv)-MOF platform with incorporated Fe(bpy)Cl3 (bpy refers to the 4′-methyl-[2,2′-bipyridine] moiety) via amine-aldehyde condensation. We show that this hybrid catalyst can reduce CO2 to form CO under visible light illumination with excellent selectivity and enhanced activity with respect to its parent MOF and corresponding homogeneous counterpart. Using steady state and transient absorption (TA) spectroscopy, we show that the enhanced photocatalytic activity of UiO-68-Fe-bpy is attributed to the elongated excited state lifetime of Fe(bpy)Cl3 after being incorporated to the UiO-68-NH2 platform. This work demonstrates the great potential of MOFs as a next generation platform for solar fuel conversion.
- Wei, Yuan-Ping,Yang, Sizhuo,Wang, Peng,Guo, Jin-Han,Huang, Jier,Sun, Wei-Yin
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- A Boron Dipyrromethene (BODIPY)-Based CuII-Bipyridine Complex for Highly Selective NO Detection
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A BODIPY-containing CuII-bipyridine complex for the simple selective fluorogenic detection of NO in air and in live cells is reported. The detection mechanism is based on NO-promoted CuII to CuI reduction, followed by demetallation of the complex, which results in the clearly enhanced emission of the boron dipyrromethene (BODIPY) unit.
- Juárez, L. Alberto,Barba-Bon, Andrea,Costero, Ana M.,Martínez-Má?ez, Ram?n,Sancen?n, Félix,Parra, Margarita,Gavi?a, Pablo,Terencio, M. Carmen,Alcaraz, M. José
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- A2B corrole with a meso-[PtII(bipy)Cl2]-substituent: Synthesis, electronic structure and highly efficient electrocatalyzed hydrogen evolutions
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Synthesis and electronic structure of meso-2,2′-bipyridine substituted H3corrole and its Pt(II) complex were described. This study demonstrates that A2B type corrole contianing meso-[PtII(bipy)Cl2] substituents are highly efficient catalysts for hydrogen evolutions with low overpotential (50 mV vs RHE), low Tafel slope (59 mV/dec) and robust catalytic behaviors. The efficient catalytic properties can be readily enhanced by charge transfer between bridging conjugated aromatic ring (corrole) and meso-[PtII(bipy)Cl2] catalytic center.
- Guo, Yingxin,Gu, Tingting,Li, Pengfei,Fu, Bo,Sun, Lei,Zhu, Weihua,Xu, Haijun,Liang, Xu
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- Rational design of a lysosome-targeting and near-infrared absorbing Ru(ii)-BODIPY conjugate for photodynamic therapy
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A Ru(ii)-BODIPY conjugate has been rationally designed and exhibits an intense absorption in the NIR region to boost lysosome-targeted PDTin vitroandin vivo. The advantages of Ru(ii) and BODIPY were successfully instilled into the conjugate to yield highly effective PDT efficacy against malignant melanoma A375 cells (PI = 3448) and A375 mice xenografts.
- Qiao, Liping,Liu, Jiangping,Han, Yunhong,Wei, Fangmian,Liao, Xinxing,Zhang, Cheng,Xie, Lina,Ji, Liangnian,Chao, Hui
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- Phosphonate-Mediated Immobilization of Rhodium/Bipyridine Hydrogenation Catalysts
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RhL2 complexes of phosphonate-derivatized 2,2′-bipyridine (bpy) ligands L were immobilized on titanium oxide particles generated in situ. Depending on the structure of the bipy ligand—number of tethers (1 or 2) to which the phosphonate end groups are attached and their location on the 2,2′-bipyridine backbone (4,4′-, 5,5′-, or 6,6′-positions)—the resulting supported catalysts showed comparable chemoselectivity but different kinetics for the hydrogenation of 6-methyl-5-hepten-2-one under hydrogen pressure. Characterization of the six supported catalysts suggested that the intrinsic geometry of each of the phosphonate-derivatized 2,2′-bipyridines leads to supported catalysts with different microstructures and different arrangements of the RhL2 species at the surface of the solid, which thereby affect their reactivity.
- Forato, Florian,Belhboub, Anouar,Monot, Julien,Petit, Marc,Benoit, Roland,Sarou-Kanian, Vincent,Fayon, Franck,Jacquemin, Denis,Queffelec, Clémence,Bujoli, Bruno
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- Functionalized core-shell Ag@TiO2 nanoparticles for enhanced Raman spectroscopy: A sensitive detection method for Cu(II) ions
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This paper demonstrates the use of surface plasmon resonance of core-shell Ag@TiO2 particles in SHINERS experiments. A copper(ii) complex grafted onto Ag@TiO2 surface was probed by Raman spectroscopy using resonance excitation profiles vs. Excitation wavelengths (514, 633 and 785 nm) to tune the Raman signals. Enhancement factors of the SHINERS assembly have been estimated and compared to the SERS effect of unmodified silver NPs colloidal dispersions. Finally, the grafting of the copper(ii) complex onto Ag@TiO2 was advantageously compared to the grafting onto Ag@SiO2 shell.
- Forato, Florian,Talebzadeh, Somayeh,Rousseau, Nicolas,Mevellec, Jean-Yves,Bujoli, Bruno,Knight, D. Andrew,Queffélec, Clémence,Humbert, Bernard
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- Novel Ru(II)/Os(II)-Exchange Homo- and Heterometallic Polypyridyl Complexes with Effective Energy Transfer
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Two novel homometallic Ru?Ru and heterometallic Ru?Os dimers and trimers, [MII(bpy)2(4-tpy-4′-methyl-2,2′-bipyridine)MII(tpy)]4+ and [MII(bpy)2](4-tpy-4′-tpy-2,2′-bipyridine)(MII(tpy))2]6+, have been first prepared and characterized. Electrochemical properties of the metal-based reversible oxidation and ligand-based reduction are measured. Spectroscopic analysis of these complexes exhibits for every Ru- or Os-based subunit an individual intense absorption spectrum extended over the entire UV and visible region. The heteronuclear complexes [RuII(bpy)2(4-tpy-4′-methyl-2,2′-bipyridine)OsII(tpy)]4+, [RuII(bpy)2](4-tpy-4′-tpy-2,2′-bipyridine)(OsII(tpy))2]6+, and [OsII(bpy)2](4-tpy-4′-tpy-2,2′-bipyridine)(RuII(tpy))2]6+ display a weak emission spectrum in the near-infrared region (NIR). The luminescence of the polynuclear assemblies is quantitatively quenched, by intramolecular energy transfer to the lower-lying metal-to-ligand charge transfer (3MLCT) and metal-centered (3MC) state of the Os(II)-based center or Ru(II)-terpyridine moiety at room temperature.
- Liu, Zi Ning,He, Chi Xian,Yin, Hong Ju,Yu, Shi Wen,Xu, Jian Bin,Dong, Jian Wei,Liu, Yan,Xia, Shu Biao,Cheng, Fei Xiang
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- Photocatalytic conversion of CO2 to CO using rhenium bipyridine platforms containing ancillary phenyl or BODIPY moieties
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Harnessing of solar energy to drive the reduction of carbon dioxide to fuels requires the development of efficient catalysts that absorb sunlight. In this work, we detail the synthesis, electrochemistry, and photophysical properties of a set of homologous fac-ReI(CO)3 complexes containing either an ancillary phenyl (8) or BODIPY (12) substituent. These studies demonstrate that both the electronic properties of the rhenium center and BODIPY chromophore are maintained for these complexes. Photolysis studies demonstrate that both assemblies 8 and 12 are competent catalysts for the photochemical reduction of CO2 to CO in dimethylformamide (DMF) using triethanolamine (TEOA) as a sacrificial reductant. Both compounds 8 and 12 display turnover frequencies (TOFs) for photocatalytic CO production upon irradiation with light (λex ≥ 400 nm) of ～5 h -1 with turnover number (TON) values of approximately 20. Although structural and photophysical measurements demonstrate that electronic coupling between the BODIPY and fac-ReI(CO)3 units is limited for complex 12, this work clearly shows that the photoactive BODIPY moiety is tolerated during catalysis and does not interfere with the observed photochemistry. When taken together, these results provide a clear roadmap for the development of advanced rhenium bipyridine complexes bearing ancillary BODIPY groups for the efficient photocatalytic reduction of CO2 using visible light.
- Andrade, Gabriel A.,Pistner, Allen J.,Yap, Glenn P. A.,Lutterman, Daniel A.,Rosenthal, Joel
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- Influence of PNIPAm on log Kf of a copolymerized 2,2′-bipyridine: Revised bifunctional ligand design for ratiometric metal-ion sensing
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Here we describe the synthesis of a model compound (1) based upon a previously reported bifunctional 2,2′-bipyridine (2). Ligand pKa and thermodynamic stability constants were investigated by potentiometric titrations for 1 in order to assess the metal-binding capabilities of 2 following subsequent incorporation within a temperature-responsive polymer that functions as a fluorescent metal-ion indicator. While the logKCu1 measured here was found to be 8.86 ± 0.05 at 25 °C, this value was previously seen to fall 2.8 orders of magnitude following copolymerization of 2 with poly(N-isopropylacrylamide) (PNIPAm). This drop in affinity was attributed to stabilization of the neutral ligand by the polymer environment and elevated temperatures at which metal-binding experiments were performed. ΔH (-54.4 kJ mol-1) and ΔS (-12.8 J K-1 mol-1) were therefore determined through variable temperature titrations in order to establish the temperature dependence of logKCu1. Doing so enabled elucidation of the overall effect that the polymer environment exerts on thermodynamic stability of copolymerized 2. Specifically, the polymer indicator was found to decrease the thermodynamic stability by 2.2 orders of magnitude, whereas elevated temperatures account for the additional 0.6 order of magnitude drop observed. This finding has implications regarding the design of future bifunctional ligands for ratiometric sensing within our temperature-responsive polymer indicator.
- Massing, Justin O.,Planalp, Roy P.
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- Layered γ-zirconium phosphate intercalated with Ru(bpy)3-viologen dyads as unusual materials for dye-sensitised solar cells: Improving efficiency by double sensitisation
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The intercalation materials prepared from the laminar salt α-zirconium phosphate and various dyads formed from Ru (bpy)3 and viologens were tested as photoactive components in dye-sensitised solar cells. The efficiencies significantly increased, up to 0.2 %, when the materials were treated with the panchromatic N535 dye. A mechanism for this double sensitisation process is proposed, which should enable further improvement of these α-ZrP-based materials as a reasonable alternative to the usual Ti-based dye-sensitised solar cells. CSIRO 2014.
- De Victoria-Rodriguez, Maria,Atienzar, Pedro,Juanes, Olga,Rodriguez-Ubis, Juan Carlos,Brunet, Ernesto,Garcia, Hermenegildo
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- Synthesis, characterization and photophysical properties of a new Cu2+ selective phosphorescent sensor
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A new Cu(II) selective phosphorescent sensor based on a cationic iridium(III) complex was synthesized and characterized. Compared with other commonly coexisting metal ions, the Ir(III) complex displayed significant phosphorescence quenching for detecting Cu2+ with a 1:1 stoichiometry in MeOH/H2O (1:1, v/v) solution. Upon addition of Cu2+, the rapid quenching of emission intensity provided a sensitive method for detection of Cu2+. The corresponding detection limit was determined to be 7.6 × 10?8 M and the association constant between the Ir(III) complex and Cu2+ was calculated to be 0.31 × 105 M?1. Luminescence imaging experiments demonstrated that this Ir(III) complex was cell permeable and suitable for monitoring intracellular Cu2+ in living Hela cells by confocal microscopy.
- Yu, Tianzhi,Yang, Qianguang,Zhu, Zeyang,Zhao, Yuling,Liu, Xiaoxiao,Wei, Chengjin,Zhang, Hui
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- A heterotrinuclear bioinspired coordination complex capable of binding to DNA and emulation of nuclease activity
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The investigation of compounds capable of strongly and selectively interacting with DNA comprises a field of research in constant development. In this work, we demonstrate that a trinuclear coordination complex based on a dinuclear Fe(III)Zn(II) core designed for biomimicry of the hydrolytic enzyme kidney bean purple acid phosphatase, containing an additional pendant arm coordinating a Pd(II) ion, has the ability to interact with DNA and to promote its hydrolytic cleavage. These results were found through analysis of plasmid DNA interaction and cleavage by the trinuclear complex 1 and its derivatives 2 and 3, in addition to the analysis of alteration in the DNA structure in the presence of the complexes through circular dichroism and DNA footprinting techniques. The suggested covalent interaction of the palladium-containing complex with DNA was analysed using an electrophoretic mobility assay, circular dichroism, high resolution gel separation techniques and kinetic analysis. This is a new and promising metal complex targeted to nucleic acids and acting in two separate ways: strong DNA interaction and hydrolytic cleavage.
- Gabriel, Philipe,Maranha, Filipy Gobbo,Nordlander, Ebbe,Neves, Ademir,Terenzi, Hernán
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- Polynuclear heteroleptic ruthenium(II) photoredox catalysts: Evaluation in blue-light-mediated, regioselective thiol-ene reactions
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Polynuclear heteroleptic ruthenium(II) photosensitisers combining either imine or amine-functionalised bipyridyl ligands were synthesised (via Schiff-base condensation/reductive amination reactions), characterised and investigated for their photoreactivity in the hydrothiolation reaction. Furthermore, electrochemical, electronic absorption and emission studies of the complexes were conducted. All the ligand-modified, heteroleptic complexes show red-shifted emission spectra (614–633 nm) relative to the canonical [Ru(bpy)3](PF6)2 complex (609 nm), attributed to the transition from the triplet MLCT excited state (3MLCT) to the ground state. The complexes were evaluated as visible-light photoredox catalysts in the radical hydrothiolation reaction of olefins (thiol-ene coupling) to afford thioethers. Control reactions performed in the absence of the photocatalyst resulted in either significantly lower yields (6%) or no product formation, demonstrating the role of the complexes as photoredox catalysts. The reactions carried out using trinuclear complexes (Ered (Ru2+*/+) = +0.300 V vs Ag/Ag+) resulted in increased yields in comparison with their respective mononuclear congeners and greater than those reported for [Ru(bpy)3](PF6)2, demonstrating the benefits of using polynuclear photocatalysts for photoinitiated redox catalysis reactions.
- Motimani, Nozuko M.,Ngubane, Siyabonga,Smith, Gregory S.
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supporting information
(2021/12/17)
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- Nitrogen-containing ligand iridium complex as well as preparation method and application thereof
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The invention provides a nitrogen-containing ligand iridium complex as well as a preparation method and application thereof. Belong to inorganic material synthesis and application technical field. After the iridium complex, 4, 4 '- dimethyl -2 and 2' - bipyridyl are oxidized to bipyridine formaldehyde by using iridium trichloride, and then hydroxylamine hydrochloride is added to form a novel nitrogen-containing ligand iridium complex after the third ligand is reacted with the benzoquinoline iridium dimer. The complex is simple in synthesis process. The prepared hypochlorite ion fluorescent probe is high in sensitivity, good in selectivity, good in anti-interference performance, wide in concentration detection range and low in detection limit.
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Paragraph 0031; 0048; 0050; 0053; 0055; 0058; 0060; ...
(2021/11/14)
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- Release of CO and Production of1O2from a Mn-BODIPY Photoactivated CO Releasing Molecule with Visible Light
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Carbon monoxide (CO) is shown to enhance the sensitivity of cancer cells to generate reactive oxygen species such as singlet oxygen (1O2) from chemotherapeutics and reduce the drug resistance. Herein, we introduced two Mn-based photoactivated CO releasing molecules conjugated with an emissive BODIPY (BDP) moiety with a general formula of Mn(CO)3(bpy-R-BDP)Br (R = H or I), labeled as Mn-bpy-H-BDP and Mn-bpy-I-BDP. While both complexes release CO with visible light, Mn-bpy-I-BDP releases CO and produces1O2from a single molecule. In addition to1O2generation, iodination of BDP red shifts the absorption of Mn-bpy-I-BDP further into the visible region and significantly increases the dark stability of the complex. Cyclic voltammetry and density functional theory (DFT) calculations suggest a Mn-based highest occupied molecular orbital (HOMO) and a BDP-based lowest unoccupied molecular orbital (LUMO) in these complexes. However, time-dependent DFT calculations suggest that the HOMO - 2(πBDP) → LUMO(πBDP*) is the main optical transition upon excitation with visible light in both complexes. The presence of a phosphorescence peak from the triplet excited state of bpy-I-BDP in both the free ligand and its Mn complex at 77 K was used as additional evidence for1O2production. We also probed formation of photo-intermediates and products during photolysis with Fourier-transform infrared,1H NMR, emission, and absorption experiments and DFT calculations.
- Pickens, Rachael N.,Pordel, Shabnam,White, Jessica K.
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p. 2983 - 2994
(2021/09/13)
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- Tuning the organelle specificity and cytotoxicity of iridium(iii) photosensitisers for enhanced phototheranostic applications
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Luminescent cyclometallated iridium(iii) complexes with a polyhedral oligomeric silsesquioxane (POSS) unit were designed as efficient theranostic agents that displayed tuneable organelle-targeting properties, minimal dark cytotoxicity and substantial photocytotoxicity even under hypoxic conditions. This journal is
- Lee, Lawrence Cho-Cheung,Lo, Kenneth Kam-Wing,Shum, Justin,Xu, Guang-Xi,Zhu, Jing-Hui
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supporting information
p. 12008 - 12011
(2021/12/01)
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- Multi-stimuli Photo and Redox-active Nanostructured Mesoporous Silica Films on Transparent Electrodes
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Silica matrices hosting transition metal guest complexes may offer remarkable platforms for the development of advanced functional devices. We report here the elaboration of ordered and vertically oriented mesoporous silica thin films containing covalently attached tris(bipyridine)iron derivatives using a combination of electrochemically assisted self-assembly (EASA) method and Huisgen cycloaddition reaction. Such a versatile approach is primarily used to bind nitrogen-based chelating ligands such as (4-[(2-propyn-1-yloxy)]4’-methyl-2,2’-bypiridine, bpy’) inside the nanochannels. Further derivatization of the bpy’-functionalized silica thin films is then achieved via a subsequent in-situ complexation step to generate [Fe(bpy)2(bpy’)]2+ inside the mesopore channels. After giving spectroscopic evidences for the presence of such complexes in the functionalized film, electrochemistry is used to transform the confined diamagnetic (S=0) (Formula presented.) species to paramagnetic (S=1/2) oxidized (Formula presented.) species in a reversible way, while blue light irradiation (λ=470 nm) enables populating the short-lived paramagnetic (S=2) (Formula presented.) excited state. [Fe(bpy)2(bpy’)]2+-functionalized ordered films are therefore both electro- and photo-active through the manipulation of the oxidation state and spin state of the confined complexes, paving the way for their integration in optoelectronic devices.
- Ahoulou, Samuel,Vilà, Neus,Pillet, Sébastien,Carteret, Cédric,Schaniel, Dominik,Walcarius, Alain
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p. 2464 - 2477
(2021/10/30)
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- Adjusting the lipid-water distribution coefficient of iridium(iii) complexes to enhance the cellular penetration and treatment efficacy to antagonize cisplatin resistance in cervical cancer
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The effective design of metal complexes to manipulate their lipid-water distribution coefficient is an appealing strategy for improving their cellular penetration and treatment efficacy. Here, we conveniently synthesized three iridium (Ir) complexes with red fluorescence via the simple non-conjugate modification of the side arm of the ligand. Bio-evaluation revealed that upon adding non-conjugate selenium (Se) arene derivatives, the lipid-water distribution coefficient of Ir-Se was found to be suitable, not only decreasing the toxic side effects of complexes to normal cells, but also effectively improving their anticancer activity via enhancing their penetration into tumor cells. Moreover, mechanistic investigations demonstrated that Ir-Se entered R-HeLa cells through endocytosis, and triggered apoptosis via the down-regulation of the mitochondrial membrane potential and excessive production of singlet oxygen, thereby possessing a highly effective cytotoxicity to antagonize cisplatin resistance. Therefore, we developed a convenient strategy to derive functional metal complexes and revealed that the introduction of Se on the side arm of the ligand provided the complexes with the capacity to reverse multidrug resistance.
- Chen, Tianfeng,Chen, Zhen,Feng, Pengju,Hou, Liyuan,Huang, Wei,Li, Yiqun
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supporting information
p. 11556 - 11564
(2020/09/07)
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- Shallow Distance Dependence for Proton-Coupled Tyrosine Oxidation in Oligoproline Peptides
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We have explored the kinetic effect of increasing electron transfer (ET) distance in a biomimetic, proton-coupled electron-transfer (PCET) system. Biological ET often occurs simultaneously with proton transfer (PT) in order to avoid the high-energy, charged intermediates resulting from the stepwise transfer of protons and electrons. These concerted proton-electron-transfer (CPET) reactions are implicated in numerous biological ET pathways. In many cases, PT is coupled to long-range ET. While many studies have shown that the rate of ET is sensitive to the distance between the electron donor and acceptor, extensions to biological CPET reactions are sparse. The possibility of a unique ET distance dependence for CPET reactions deserves further exploration, as this could have implications for how we understand biological ET. We therefore explored the ET distance dependence for the CPET oxidation of tyrosine in a model system. We prepared a series of metallopeptides with a tyrosine separated from a Ru(bpy)32+ complex by an oligoproline bridge of increasing length. Rate constants for intramolecular tyrosine oxidation were measured using the flash-quench transient absorption technique in aqueous solutions. The rate constants for tyrosine oxidation decreased by 125-fold with three added proline residues between tyrosine and the oxidant. By comparison, related intramolecular ET rate constants in very similar constructs were reported to decrease by 4-5 orders of magnitude over the same number of prolines. The observed shallow distance dependence for tyrosine oxidation is proposed to originate in part from the requirement for stronger oxidants, leading to a smaller hole-transfer effective tunneling barrier height. The shallow distance dependence observed here and extensions to distance-dependent CPET reactions have potential implications for long-range charge transfers.
- Koronkiewicz, Brian,Swierk, John,Regan, Kevin,Mayer, James M.
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supporting information
p. 12106 - 12118
(2020/08/06)
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- Intracellular Reactions Promoted by Bis(histidine) Miniproteins Stapled Using Palladium(II) Complexes
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The generation of catalytically active metalloproteins inside living mammalian cells is a major research challenge at the interface between catalysis and cell biology. Herein we demonstrate that basic domains of bZIP transcription factors, mutated to include two histidine residues at i and i+4 positions, react with palladium(II) sources to generate catalytically active, stapled pallado-miniproteins. The resulting constrained peptides are efficiently internalized into living mammalian cells, where they perform palladium-promoted depropargylation reactions without cellular fixation. Control experiments confirm the requirement of the peptide scaffolding and the palladium staple for attaining the intracellular reactivity.
- Gutiérrez-González, Alejandro,Learte-Aymamí, Soraya,Mascare?as, José L.,Vidal, Cristian
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supporting information
p. 9149 - 9154
(2020/04/15)
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- RHODAMINE TRIPLET STATE COMPLEX AND PREPARATION AND PHOTODYNAMIC THERAPY (PDT) STUDY THEREOF
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Through the use of a rhodamine appended chelate, a versatile strategy has been demonstrated to generate mitochondria-targeting photosensitizers via the incorporation of variety of luminescent transition metal systems. The generation of triplet excited state of rhodamine moiety endows the complexes with mitochondria-targeting photosensitizing ability to form singlet oxygen ( 1O 2) for use as photodynamic therapy (PDT) agent. The combination of rhodamine organic dye and luminescent transition metal centers in such hybrid systems exhibits the synergistic merits, including low dark cytotoxicity, selective tumor cell uptake, high molar absorptivity for low-energy excitation in the visible region, and high photostability.
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Page/Page column 17
(2020/03/05)
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- Bioorthogonal "labeling after Recognition" Affording an FRET-Based Luminescent Probe for Detecting and Imaging Caspase-3 via Photoluminescence Lifetime Imaging
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Bis-labeling with a luminescent energy donor/acceptor pair onto biological substrates affords probes which give FRET readouts for the detection of interaction partners. However, the covalently bound luminophores bring about steric hindrance and nonspecific interaction, which probably perturb the biological recognition. Herein, we designed a highly sensitive and specific "labeling after recognition" sensing approach, where luminophore labeling occurred after the biological recognition. Taking the cutting enzyme caspase-3 as an example, we demonstrated the detection of its catalytic activity in solution and apoptotic cells using the tetrapeptide motif Asp-Glu-Val-Asp (DEVD) as the cleavable substrate, and an iridium(III) complex and a rhodamine derivative as the energy donor/acceptor pair. The DEVD tetrapeptide was modified with an azide and a GK-norbornylene groups at the amino and carboxyl terminuses, respectively, which allowed donor/acceptor bis-labeling via two independent catalysis-free bioorthogonal reactions. The phosphorescence lifetime of the iridium(III) complex was quenched upon bis-labeling owing to the intracellular FRET to the rhodamine derivative, and significantly elongated upon the peptide being catalytically cleaved by caspase-3. Interestingly, the sensitivity and efficiency of the lifetime responses were much higher in the "labeling after recognition" sensing approach. Molecular docking analysis showed that the steric hindrance and nonspecific interactions partially inhibited the biological recognition of the DEVD substrate by caspase-3. The imaging of the catalytic activity of caspase-3 in apoptotic cells was demonstrated via photoluminescence lifetime imaging microscopy. Lifetime analysis not only confirmed the occurrence of intracellular bioorthogonal bis-labeling and catalytic cleavage, but also showed the extent to which the two dynamic processes occurred.
- Dai, Peiling,Huang, Wei,Liu, Shujuan,Song, Linna,Wang, Ling,Wang, Yun,Wu, Qi,Zhang, Kenneth Yin,Zhao, Qiang,Zhu, Hengyu
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supporting information
p. 1057 - 1064
(2020/02/20)
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- Double-phosphorescence emission probe and preparation method thereof
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The invention discloses a double-phosphorescence emission probe and a preparation method thereof; the double-phosphorescence emission probe capable of detecting oxygen and metal ions is constructed byutilizing the response of a bis(2-pyridylmethyl)amine structure to metal ions and the response of a double-phosphorescence emission iridium complex to oxygen. Compared with a single-phosphorescence emission iridium complex probe disclosed in the prior art, the double-phosphorescence emission probe provides a new idea for simultaneous detection of multiple detection targets by a single probe; thepreparation process of the double-phosphorescence emission iridium complex is simple, reaction conditions are mild, and operability is high.
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Paragraph 0036; 0040; 0042; 0043
(2020/06/16)
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- Preparation method of ruthenium complex and acquired immune deficiency syndrome virus reverse transcriptase inhibition application of ruthenium complex
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The invention belongs to the field of researches and development of acquired immune deficiency syndrome virus inhibitors and discloses a preparation method of a ruthenium complex and acquired immune deficiency syndrome virus reverse transcriptase inhibition application of the ruthenium complex. The invention designs a novel synthesis method of a polypyridine ruthenium complex; the complex has highpurity and high yield and has good water solubility and excellent light spectrum property. The polypyridine ruthenium complex provided by the invention has a capability of selectively combining a TARregion on acquired immune deficiency syndrome virus RNA (Ribonucleic Acid), and can be used for blocking a reverse transcription process of the reverse transcriptase on the virus RNA to inhibit the copying of the virus RNA. The polypyridine ruthenium complex provided by the invention is an acquired immune deficiency syndrome virus RNA selective binding reagent with high affinity and an acquired immune deficiency syndrome virus reverse transcriptase inhibitor with high activity, and is an acquired immune deficiency syndrome virus medicine with extremely good application potential.
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Paragraph 0019
(2019/02/06)
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- Phosphorescence iridium complex with singlet oxygen detection effect and preparation method and applications thereof
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The invention provides a phosphorescence iridium complex with a singlet oxygen detection effect and a preparation method and applications thereof. The complex is composed of a cyclo-metal ligand, a metal center, and an auxiliary ligand of a singlet oxygen detection functional group. The structural formula of the complex is represented in the description. The provided complex can be combined with singlet oxygen under the light radiation and can be used to detect singlet oxygen; after the complex is combined with singlet oxygen, the complex can be deeply co-dyed with a commercial mitochondrion dye, thus the complex can be used to target mitochondria; and moreover, the complex can be applied to biological imaging and can be used to detect the change of singlet oxygen in live cells. The provided phosphorescence iridium complex has an important application prospect in the fields of bio-imaging and singlet oxygen detection.
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Paragraph 0058-0061
(2019/01/08)
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- Ionic type iridium complex with double phosphorescence emission properties as well as preparation method and application of ionic type iridium complex
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The invention belongs to the technical field of organic photoelectric functional materials, and particularly relates to an ionic type iridium complex with double phosphorescence emission properties as well as a preparation method and an application of the ionic type iridium complex. The complex comprises a metal center and cyclometalated ligands. The preparation method comprises steps as follows: dichloro bridge is prepared from a phenylpyridine derivative and iridium(III) chloride trihydrate through a coordination reaction, and the ionic type iridium complex with the double phosphorescence emission properties is prepared from dichloro bridge and a dipyridyl derivative or sodium carbonate through coordination reaction. The ionic type iridium complex with the double phosphorescence emission properties can be applied to the fields of biological detection and biological imaging for hypoxic oxygen-enriched conditions; a diagnosis and treatment integrated multifunctional probe based on the ionic type iridium complex with the double phosphorescence emission properties has great potential in further biomedicine application.
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Paragraph 0036-0039
(2018/01/11)
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- Influence of Proton Acceptors on the Proton-Coupled Electron Transfer Reaction Kinetics of a Ruthenium-Tyrosine Complex
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A polypyridyl ruthenium complex with fluorinated bipyridine ligands and a covalently bound tyrosine moiety was synthesized, and its photo-induced proton-coupled electron transfer (PCET) reactivity in acetonitrile was investigated with transient absorption spectroscopy. Using flash-quench methodology with methyl viologen as an oxidative quencher, a Ru3+ species is generated that is capable of initiating the intramolecular PCET oxidation of the tyrosine moiety. Using a series of substituted pyridine bases, the reaction kinetics were found to vary as a function of proton acceptor concentration and identity, with no significant H/D kinetic isotope effect. Through analysis of the kinetics traces and comparison to a control complex without the tyrosine moiety, PCET reactivity was found to proceed through an equilibrium electron transfer followed by proton transfer (ET-PT) pathway in which irreversible deprotonation of the tyrosine radical cation shifts the ET equilibrium, conferring a base dependence on the reaction. Comprehensive kinetics modeling allowed for deconvolution of complex kinetics and determination of rate constants for each elementary step. Across the five pyridine bases explored, spanning a range of 4.2 pKa units, a linear free-energy relationship was found for the proton transfer rate constant with a slope of 0.32. These findings highlight the influence that proton transfer driving force exerts on PCET reaction kinetics.
- Lennox, J. Christian,Dempsey, Jillian L.
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p. 10530 - 10542
(2017/12/01)
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- COLLAGEN PEPTIDE CONJUGATES AND USES THEREFOR
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Described herein are conjugates of collagen peptides and metal binding agents and compositions resulting therefrom, useful in various tissue engineering and regeneration applications, in cell culture, cell adhesion, cosmetic surgery, construction of artificial skin substitutes, management of severe burns and burn surgery, reconstruction of bone and a wide variety of dental, orthopedic and surgical purposes, as drug delivery vehicles and in delivering populations of cells to a site of disease or injury.
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Paragraph 0120
(2016/08/23)
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- Membrane staining dyes containing phosphorescent transition metal polypyridine complexes
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The present invention is concerned with a staining dye for staining a biological cell, comprising dye molecules with a positively charged polar head group for attraction to cell membrane of the cell and for refraining the dye molecules from entering the cytoplasm, and one or more hydrophobic groups for interaction with phospholipids of the cell membrane. The dye molecules are phosphorescent transition metal polypyridine complexes having a metal center and ligands which are non-organic fluorophores.
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Page/Page column 4; 5; 9
(2016/09/28)
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- DYE SENSITIZED SOLAR CELL COMPRISING NOVEL BIPYRIDINE RUTHEMIUM BASED DYE
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The present invention provides a dye-sensitized solar cell comprising: a first electrode; an optical absorbing layer formed on one surface of the first electrode, and including at least one of bipyridine ruthenium-based compounds represented by the chemical formula (1), chemical formula (2), and chemical formula (3) as a bipyridine ruthenium-based dye; a second electrode disposed to face the first electrode having the optical absorbing layer formed thereon; and an electrolyte layer formed between the first electrode and the second electrode.COPYRIGHT KIPO 2016
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Paragraph 0053-0056
(2016/10/17)
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- Synthesis and electrocatalytic water oxidation by electrode-bound helical peptide chromophore-catalyst assemblies
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Artificial photosynthesis based on dye-sensitized photoelectrosynthesis cells requires the assembly of a chromophore and catalyst in close proximity on the surface of a transparent, high band gap oxide semiconductor for integrated light absorption and catalysis. While there are a number of approaches to assemble mixtures of chromophores and catalysts on a surface for use in artificial photosynthesis based on dye-sensitized photoelectrosynthesis cells, the synthesis of discrete surface-bound chromophore-catalyst conjugates is a challenging task with few examples to date. Herein, a versatile synthetic approach and electrochemical characterization of a series of oligoproline-based light-harvesting chromophore-water-oxidation catalyst assemblies is described. This approach combines solid-phase peptide synthesis for systematic variation of the backbone, copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) as an orthogonal approach to install the chromophore, and assembly of the water-oxidation catalyst in the final step. Importantly, the catalyst was found to be incompatible with the conditions both for amide bond formation and for the CuAAC reaction. The modular nature of the synthesis with late-stage assembly of the catalyst allows for systematic variation in the spatial arrangement of light-harvesting chromophore and water-oxidation catalyst and the role of intrastrand distance on chromophore-catalyst assembly properties. Controlled potential electrolysis experiments verified that the surface-bound assemblies function as water-oxidation electrocatalysts, and electrochemical kinetics data demonstrate that the assemblies exhibit greater than 10-fold rate enhancements compared to the homogeneous catalyst alone.
- Ryan, Derek M.,Coggins, Michael K.,Concepcion, Javier J.,Ashford, Dennis L.,Fang, Zhen,Alibabaei, Leila,Ma, Da,Meyer, Thomas J.,Waters, Marcey L.
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supporting information
p. 8120 - 8128
(2014/08/18)
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- Design and synthesis of bipyridine platinum(II) bisalkynyl fullerene donor-chromophore-acceptor triads with ultrafast charge separation
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Donor-chromophore-acceptor triads, (PTZ)2-Pt(bpy)-C60 and (tBuPTZ)2-Pt(bpy)-C60, along with their model compound, (Ph)2-Pt(bpy)-C60, have been synthesized and characterized; their photophysical and electrochemical properties have been studied, and the origin of the absorption and emission properties has been supported by computational studies. The photoinduced electron transfer reactions have been investigated using the femtosecond and nanosecond transient absorption spectroscopy. In dichloromethane, (Ph)2-Pt(bpy)-C 60 shows ultrafast triplet-triplet energy transfer from the 3MLCT/LLCT excited state within 4 ps to give the 3C 60* state, while in (PTZ)2-Pt(bpy)-C60 and (tBuPTZ)2-Pt(bpy)-C60, charge-separated state forms within 400 fs from the 3MLCT/LLCT excited state with efficiency of over 0.90, and the total efficiency with the contribution of 3C60* is estimated to be 0.99. Although the forward electron transfer reactions are very rapid, the charge-separated state recombines to the singlet ground state at a time of hundreds of nanoseconds because of the difference in spin multiplicity between the charge-separated state and the ground state.
- Lee, Sai-Ho,Chan, Chris Tsz-Leung,Wong, Keith Man-Chung,Lam, Wai Han,Kwok, Wai-Ming,Yam, Vivian Wing-Wah
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p. 10041 - 10052
(2014/08/05)
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- Synthesis and photoinduced electron transfer in platinum(ii) bis(N-(4-ethynylphenyl)carbazole)bipyridine fullerene complexes
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Platinum(ii) bis(N-(4-ethynylphenyl)carbazole)bipyridine fullerene complexes, (Cbz)2-Pt(bpy)-C60 and (tBuCbz)2-Pt(bpy)-C60, were synthesized. Their photophysical properties were studied by electronic absorption and emission spectroscopy and the origin of the transitions was supported by computational studies. The electrochemical properties were also studied and the free energies for charge-separation and charge-recombination processes were evaluated. The photoinduced electron transfer reactions in the triads were investigated by femtosecond and nanosecond transient absorption spectroscopy. In dichloromethane, both triads undergo ultrafast charge separation from the 3MLCT/LLCT excited state within 300 fs to yield their respective triplet charge-separated (CS) states, namely (Cbz)2+-Pt(bpy)-C60- and (tBuCbz)2+-Pt(bpy)-C60-, and the CS states would undergo charge recombination to give the 3C60 state, which subsequently decays to the ground state in 22-28 μs. This journal is
- Lee, Sai-Ho,Chan, Chris Tsz-Leung,Wong, Keith Man-Chung,Lam, Wai Han,Kwok, Wai-Ming,Yam, Vivian Wing-Wah
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p. 17624 - 17634
(2015/02/02)
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- Bifunctional mesoporous silica nanoparticles as cooperative catalysts for the Tsuji-Trost reaction-tuning the reactivity of silica nanoparticles
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Bifunctional mesoporous silica nanoparticles (MSNs) bearing Pd-complexes and additional basic sites were prepared and tested as cooperative active catalysts in the Tsuji-Trost allylation of ethyl acetoacetate. Functionalization of the MSNs was realized by postmodification using click-chemistry. The selectivity of mono versus double allylation was achieved by control of reaction temperature and the nature of the catalyst.
- Dickschat, Arne T.,Behrends, Frederik,Surmiak, Sabrina,Wei?, Mark,Eckert, Hellmut,Studer, Armido
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supporting information
p. 2195 - 2197
(2013/03/29)
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