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A New Unnatural Amino Acid Derived from the Modification of 4′-(p-tolyl)-2,2′:6′,2″-terpyridine and Its Mixed-Ligand Complexes with Ruthenium: Synthesis, Characterization, and Photophysical Properties. CHEMISTRY 2023. [DOI: 10.3390/chemistry5010012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The modification of the methyl group of 4′-(p-tolyl)-2,2′:6′,2″-terpyridine produced the novel unnatural amino acid 3-(4-([2,2′:6′,2″-terpyridin]-4′-yl)phenyl)-2-aminopropanoic acid (phet). Mononuclear heteroleptic ruthenium complexes of the general formulae [Ru(L1)(L2)](PF6)2 (L1 = 2-acetylamino-2-(4-[2,2′:6′,2″]terpyridine-4′-yl-benzyl)-malonic acid diethyl ester, (phem), 3-(4-([2,2′:6′,2″-terpyridin]-4′-yl)phenyl)-2-aminopropanoic acid, (phet), and L2 = 2,2′:6′,2″-terpyridine (tpy), 4′-phenyl-2,2′:6′,2″-terpyridine (ptpy), 4′-(p-tolyl)-2,2′:6′,2″-terpyridine (mptpy)), as well as the homoleptic [Ru(phem)2](PF6)2 and [Ru(phet)2](PF6)2, were synthesized and characterized by means of NMR spectroscopic techniques, elemental analysis, and high-resolution mass spectrometry. The photophysical properties of the synthesized complexes were also studied.
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Krivdin LB. Computational 1 H and 13 C NMR in structural and stereochemical studies. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:733-828. [PMID: 35182410 DOI: 10.1002/mrc.5260] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
Present review outlines the advances and perspectives of computational 1 H and 13 C NMR applied to the stereochemical studies of inorganic, organic, and bioorganic compounds, involving in particular natural products, carbohydrates, and carbonium ions. The first part of the review briefly outlines theoretical background of the modern computational methods applied to the calculation of chemical shifts and spin-spin coupling constants at the DFT and the non-empirical levels. The second part of the review deals with the achievements of the computational 1 H and 13 C NMR in the stereochemical investigation of a variety of inorganic, organic, and bioorganic compounds, providing in an abridged form the material partly discussed by the author in a series of parent reviews. Major attention is focused herewith on the publications of the recent years, which were not reviewed elsewhere.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
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Lifshits LM, Roque JA, Cole HD, Thummel RP, Cameron CG, McFarland SA. NIR-Absorbing Ru II Complexes Containing α-Oligothiophenes for Applications in Photodynamic Therapy. Chembiochem 2020; 21:3594-3607. [PMID: 32761725 PMCID: PMC7736147 DOI: 10.1002/cbic.202000419] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/03/2020] [Indexed: 12/12/2022]
Abstract
The design of near-infrared (NIR)-active photosensitizers (PSs) for light-based cancer treatments such as photodynamic therapy (PDT) has been a challenge. While several NIR-RuII scaffolds have been reported, this approach has not been proven in cells. This is the first report of NIR-RuII PSs that are phototoxic to cancer cells, including highly pigmented B16F10 melanoma cells. The PS family incorporated a bis(1,8-naphthyridine)-based ligand (tpbn), a bidentate thiophene-based ligand (nT; n=0-4), and a monodentate 4-picoline ligand (4-pic). All compounds absorbed light >800 nm with maxima near 730 nm. Transient absorption (TA) measurements indicated that n=4 thiophene rings (4T) positioned the PDT-active triplet intraligand charge transfer (3 ILCT) excited state in energetic proximity to the lowest-lying triplet metal-to-ligand charge transfer (3 MLCT). 4T had low-micromolar phototoxicity with PIvis and PI733nm values as large as 90 and 12, respectively. Spectroscopic studies suggested that the longer-lived (τTA =3-6 μs) 3 ILCT state was accessible from the 3 MLCT state, but energetically uphill in the overall photophysics. The study highlights that phototoxic effects can be achieved with NIR-absorbing RuII PSs as long as the reactive 3 ILCT states are energetically accessible from the low-energy 3 MLCT states. It also demonstrates that tissue-penetrating NIR light can be used to activate the PSs in highly pigmented cells where melanin attenuates shorter wavelengths of light.
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Affiliation(s)
- Liubov M. Lifshits
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
| | - John A. Roque
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, USA
| | - Houston D. Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
| | - Randolph P. Thummel
- Department of Chemistry, University of Houston, 112 Fleming Building, Houston, Texas, 77204-5003, USA
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
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Krivdin LB. Computational 1 H NMR: Part 2. Chemical applications. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:5-14. [PMID: 31125992 DOI: 10.1002/mrc.4896] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 05/12/2019] [Accepted: 05/18/2019] [Indexed: 06/09/2023]
Abstract
This is the second one of three closely interrelated reviews dealing with computation of 1 H NMR chemical shifts and 1 H-1 H spin-spin coupling constants prepared for Magnetic Resonance in Chemistry. Presented in this review are some basic notes and illustrative examples of how modern computational 1 H NMR could be used for structural elucidation and stereoelectronic studies of the medium-sized organic molecules involving saturated, unsaturated, aromatic, and heteroaromatic compounds together with their functional derivatives and coordination complexes to get deeper insight into their stereochemical structure and stereodynamic behavior.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033, Irkutsk, Russia
- Chair of Chemistry, Angarsk State Technical University, Tchaikovsky St. 60, 665835, Angarsk, Russia
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Krivdin LB. Computational protocols for calculating 13C NMR chemical shifts. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 112-113:103-156. [PMID: 31481156 DOI: 10.1016/j.pnmrs.2019.05.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 05/19/2019] [Accepted: 05/20/2019] [Indexed: 06/10/2023]
Abstract
The most recent results dealing with the computation of 13C NMR chemical shifts in chemistry (small molecules, saturated, unsaturated and aromatic compounds, heterocycles, functional derivatives, coordination complexes, carbocations, and natural products) are reviewed, paying special attention to theoretical background and accuracy, the latter involving solvent effects, vibrational corrections, and relativistic effects.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033 Irkutsk, Russia.
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Krivdin LB. Calculation of 15N NMR chemical shifts: Recent advances and perspectives. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2017; 102-103:98-119. [PMID: 29157495 DOI: 10.1016/j.pnmrs.2017.08.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 08/21/2017] [Accepted: 08/21/2017] [Indexed: 06/07/2023]
Abstract
Recent advances in computation of 15N NMR chemical shifts are reviewed, concentrating mainly on practical aspects of computational protocols and accuracy factors. The review includes the discussion of the level of theory, the choice of density functionals and basis sets together with taking into account solvent effects, rovibrational corrections and relativistic effects. Computational aspects of 15N NMR are illustrated for the series of neutral and protonated open-chain nitrogen-containing compounds and nitrogen heterocycles, coordination and intermolecular complexes.
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Affiliation(s)
- Leonid B Krivdin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Favorsky St. 1, 664033 Irkutsk, Russia.
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Zare D, Doistau B, Nozary H, Besnard C, Guénée L, Suffren Y, Pelé AL, Hauser A, Piguet C. CrIII as an alternative to RuII in metallo-supramolecular chemistry. Dalton Trans 2017; 46:8992-9009. [DOI: 10.1039/c7dt01747b] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Semi-labile [Cr(tpy)(CF3SO3)3] precursors can be exploited for building rod-like dinuclear dyads, in which paramagnetic and luminescent trivalent CrIII replace diamagnetic RuII for unravelling intermetallic communication in supramolecular architectures.
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Affiliation(s)
- Davood Zare
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Benjamin Doistau
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Homayoun Nozary
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Céline Besnard
- Laboratory of Crystallography
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Laure Guénée
- Laboratory of Crystallography
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Yan Suffren
- Department of Physical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Anne-Laure Pelé
- Department of Physical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Andreas Hauser
- Department of Physical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Claude Piguet
- Department of Inorganic and Analytical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
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Wang R, Both SK, Geven M, Calucci L, Forte C, Dijkstra PJ, Karperien M. Kinetically stable metal ligand charge transfer complexes as crosslinks in nanogels/hydrogels: Physical properties and cytotoxicity. Acta Biomater 2015; 26:136-44. [PMID: 26292264 DOI: 10.1016/j.actbio.2015.08.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 07/23/2015] [Accepted: 08/16/2015] [Indexed: 11/19/2022]
Abstract
A terpyridine end-functionalized 8-arm poly(ethylene glycol) was prepared using the reaction of a 4'-aminopentanoxy substituted terpyridine with a p-nitrophenyl chloroformate activated PEG-(OH)8. Supramolecular complexation of the polymer terpyridine moieties by Fe(2+) ions was investigated using NMR, UV-Vis and dynamic light scattering experiments. At low concentrations addition of Fe(2+) ions to an aqueous solution of the polymer conjugate afforded nanogels with a single size distribution around 250 nm. At concentrations above 3 wt%, and at a 1:2 metal to ligand molar ratio, hydrogels were formed with increasing mechanical properties at increasing polymer concentrations. Using bovine chondrocytes, the biocompatibility and potential cytotoxicity of the polymer conjugate, nanogels and hydrogels were studied. The polymer conjugate with free ligands was toxic to the cells likely due to depletion of essential metal ions. When the terpyridine groups were complexed with Fe(2+) ions, both nanogel suspensions and hydrogels showed no cytotoxicity in direct contact with chondrocytes. Indirect contact of gels with chondrocytes using transwells revealed the absence of toxic components by leaching. A Live-Dead assay on chondrocytes encapsulated in the hydrogels indicated that the hydrogels are cytocompatible, revealing the potential use of these materials for biomedical and pharmaceutical applications. STATEMENT OF SIGNIFICANCE The binding between transition metal ions and ligands with multiple binding sites can be almost as strong as covalent bonds. This metal-ligand charge transfer (MLCT) complexation was used to crosslink water soluble polymers into hydrogels. This approach to novel materials may find applications in the biomedical and pharmaceutical fields. Transition metal ions are essential trace elements present in tissue but up to now no cytotoxicity data of free ligands are available. Data presented show that free ligands are toxic to cells likely by depletion of trace metal ions, whereas kinetically stable complexes are not cytotoxic even when embedded in hydrogels. These results provide fundamental issues to be considered in the design of hydrogels crosslinked through metal ligand complexation.
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Affiliation(s)
- Rong Wang
- MIRA - Institute for Biomedical Technology and Technical Medicine and Department of Developmental Bioengineering, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | - Sanne K Both
- MIRA - Institute for Biomedical Technology and Technical Medicine and Department of Developmental Bioengineering, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Mike Geven
- MIRA - Institute for Biomedical Technology and Technical Medicine and Department of Developmental Bioengineering, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Lucia Calucci
- Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle Ricerche - CNR, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Claudia Forte
- Istituto di Chimica dei Composti OrganoMetallici, Consiglio Nazionale delle Ricerche - CNR, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Pieter J Dijkstra
- MIRA - Institute for Biomedical Technology and Technical Medicine and Department of Developmental Bioengineering, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Marcel Karperien
- MIRA - Institute for Biomedical Technology and Technical Medicine and Department of Developmental Bioengineering, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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Battistin F, Balducci G, Demitri N, Iengo E, Milani B, Alessio E. (15)N NMR spectroscopy unambiguously establishes the coordination mode of the diimine linker 2-(2'-pyridyl)pyrimidine-4-carboxylic acid (cppH) in Ru(ii) complexes. Dalton Trans 2015; 44:15671-82. [PMID: 26251967 DOI: 10.1039/c5dt02361k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigated the reactivity of three Ru(ii) precursors -trans,cis,cis-[RuCl2(CO)2(dmso-O)2], cis,fac-[RuCl2(dmso-O)(dmso-S)3], and trans-[RuCl2(dmso-S)4] - towards the diimine linker 2-(2'-pyridyl)pyrimidine-4-carboxylic acid (cppH) or its parent compound 4-methyl-2-(2'-pyridyl)pyrimidine ligand (mpp), in which a methyl group replaces the carboxylic group on the pyrimidine ring. In principle, both cppH and mpp can originate linkage isomers, depending on how the pyrimidine ring binds to ruthenium through the nitrogen atom ortho (N(o)) or para (N(p)) to the group in position 4. The principal aim of this work was to establish a spectroscopic fingerprint for distinguishing the coordination mode of cppH/mpp also in the absence of an X-ray structural characterization. By virtue of the new complexes described here, together with the others previously reported by us, we successfully recorded {(1)H,(15)N}-HMBC NMR spectra at natural abundance of the (15)N isotope on a consistent number of fully characterized Ru(ii)-cppH/mpp compounds, most of them being stereoisomers and/or linkage isomers. Thus, we found that (15)N NMR chemical shifts unambiguously establish the binding mode of cppH and mpp - either through N(o) or N(p)- and can be conveniently applied also in the absence of the X-ray structure. In fact, coordination of cppH to Ru(ii) induces a marked upfield shift for the resonance of the N atoms directly bound to the metal, with coordination induced shifts (CIS) ranging from ca.-45 to -75 ppm, depending on the complex, whereas the unbound N atom resonates at a frequency similar to that of the free ligand. Similar results were found for the complexes of mpp. This work confirmed our previous finding that cppH has no binding preference, whereas mpp binds exclusively through N(p). Interestingly, the two cppH linkage isomers trans,cis-[RuCl2(CO)2(cppH-κN(p))] (5) and trans,cis-[RuCl2(CO)2(cppH-κN(o))] (6) were easily obtained in pure form by exploiting their different solubility properties.
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Affiliation(s)
- Federica Battistin
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy.
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Benson CR, Hui AK, Parimal K, Cook BJ, Chen CH, Lord RL, Flood AH, Caulton KG. Multiplying the electron storage capacity of a bis-tetrazine pincer ligand. Dalton Trans 2014; 43:6513-24. [PMID: 24623103 DOI: 10.1039/c4dt00341a] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An unexpected doubling in redox storage emerging from a new pincer ligand upon bis-ligation of iron(ii) is described. When tetrazine arms are present at the two ortho positions of pyridine, the resulting bis-tetrazinyl pyridine (btzp) pincer ligand displays a single one-electron reduction at ca. -0.85 V vs. Ag/AgCl. Complexation to iron, giving the cation Fe(btzp)2(2+), shows no oxidation but four reduction waves in cyclic voltammetry instead of the two expected for the two constituent ligands. Mossbauer, X-ray diffraction and NMR studies show the iron species to contain low spin Fe(ii), but with evidence of back donation from iron to the pincer ligands. CV and UV-Vis spectroelectrochemistry, as well as titration studies as monitored by CV, electronic spectra and EPR reveal the chemical reversibility of forming the reduced species. DFT and EPR studies show varying degrees of delocalization of unpaired spin in different species, including that of a btzp(-1) radical anion, partnered with various cations.
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Affiliation(s)
- Christopher R Benson
- Indiana University, Department of Chemistry, 800 East Kirkwood Avenue, Bloomington, IN, USA.
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TERAMOTO K, NISHIDE T, OKUMURA S, TAKAO K, IKEDA Y. Studies on Metal Complexes as Active Materials in Redox-flow Battery Using Ionic Liquids as Electrolyte: Electrochemical Properties of [Fe(L)x][Tf2N]2 (L: Multidentate Ligands, x = 2 or 3) in 1-Butyl-3-methylimidazolium Bis(Trifluoromethylsulfonyl)Imide, [BMI][Tf2N]. ELECTROCHEMISTRY 2014. [DOI: 10.5796/electrochemistry.82.566] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Scanu R, Manca P, Zucca A, Sanna G, Spano N, Seeber R, Zanardi C, Pilo MI. Homoleptic Ru(II) complex with terpyridine ligands appended with terthiophene moieties: Synthesis, characterization and electropolymerization. Polyhedron 2013. [DOI: 10.1016/j.poly.2012.09.056] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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