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Springer CS, Pike MM, Barbara TM. A Futile Cycle?: Tissue Homeostatic Trans-Membrane Water Co-Transport: Kinetics, Thermodynamics, Metabolic Consequences. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.17.589812. [PMID: 38659823 PMCID: PMC11042311 DOI: 10.1101/2024.04.17.589812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The phenomenon of active trans-membrane water cycling (AWC) has emerged in little over a decade. Here, we consider H2O transport across cell membranes from the origins of its study. Historically, trans-membrane water transport processes were classified into: A) compensating bidirectional fluxes ("exchange"), and B) unidirectional flux ("net flow") categories. Recent literature molecular structure determinations and molecular dynamic (MD) simulations indicate probably all the many different hydrophilic substrate membrane co-transporters have membrane-spanning hydrophilic pathways and co-transport water along with their substrates, and that they individually catalyze category A and/or B water flux processes, although usually not simultaneously. The AWC name signifies that, integrated over the all the cell's co-transporters, the rate of homeostatic, bidirectional trans-cytolemmal water exchange (category A) is synchronized with the metabolic rate of the crucial Na+,K+-ATPase (NKA) enzyme. A literature survey indicates the stoichiometric (category B) water/substrate ratios of individual co-transporters are often very large. The MD simulations also suggest how different co-transporter reactions can be kinetically coupled molecularly. Is this (Na+,K+-ATPase rate-synchronized) cycling futile, or is it consequential? Conservatively representative literature metabolomic and proteinomic results enable comprehensive free energy analyses of the many transport reactions with known water stoichiometries. Free energy calculations, using literature intracellular pressure (Pi) values reveals there is an outward trans-membrane H2O barochemical gradient of magnitude comparable to that of the well-known inward Na+ electrochemical gradient. For most co-influxers, these gradients are finely balanced to maintain intracellular metabolite concentration values near their consuming enzyme Michaelis constants. The thermodynamic analyses include glucose, glutamate-, gamma-aminobutyric acid (GABA), and lactate- transporters. 2%-4% Pi alterations can lead to disastrous concentration levels. For the neurotransmitters glutamate- and GABA, very small astrocytic Pi changes can allow/disallow synaptic transmission. Unlike the Na+ and K+ electrochemical steady-states, the H2O barochemical steady-state is in (or near) chemical equilibrium. The analyses show why the presence of aquaporins (AQPs) does not dissipate the trans-membrane pressure gradient. A feedback loop inherent in the opposing Na+ electrochemical and H2O barochemical gradients regulates AQP-catalyzed water flux as an integral AWC aspect. These results also require a re-consideration of the underlying nature of Pi. Active trans-membrane water cycling is not futile, but is inherent to the cell's "NKA system" - a new, fundamental aspect of biology.
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Affiliation(s)
- Charles S Springer
- Advanced Imaging Research Center
- Department of Chemical Physiology and Biochemistry
- Department of Biomedical Engineering
- Brenden-Colson Center for Pancreatic Care
- Knight Cancer Institute, Oregon Health & Science University; Portland, Oregon
| | - Martin M Pike
- Advanced Imaging Research Center
- Department of Biomedical Engineering
- Knight Cancer Institute, Oregon Health & Science University; Portland, Oregon
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2
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Migliore R, Biver T, Barone G, Sgarlata C. Quantitative Analysis of the Interactions of Metal Complexes and Amphiphilic Systems: Calorimetric, Spectroscopic and Theoretical Aspects. Biomolecules 2022; 12:biom12030408. [PMID: 35327600 PMCID: PMC8946196 DOI: 10.3390/biom12030408] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 01/27/2023] Open
Abstract
Metals and metal-based compounds have many implications in biological systems. They are involved in cellular functions, employed in the formation of metal-based drugs and present as pollutants in aqueous systems, with toxic effects for living organisms. Amphiphilic molecules also play important roles in the above bio-related fields as models of membranes, nanocarriers for drug delivery and bioremediating agents. Despite the interest in complex systems involving both metal species and surfactant aggregates, there is still insufficient knowledge regarding the quantitative aspects at the basis of their binding interactions, which are crucial for extensive comprehension of their behavior in solution. Only a few papers have reported quantitative analyses of the thermodynamic, kinetic, speciation and binding features of metal-based compounds and amphiphilic aggregates, and no literature review has yet addressed the quantitative study of these complexes. Here, we summarize and critically discuss the recent contributions to the quantitative investigation of the interactions of metal-based systems with assemblies made of amphiphilic molecules by calorimetric, spectrophotometric and computational techniques, emphasizing the unique picture and parameters that such an analytical approach may provide, to support a deep understanding and beneficial use of these systems for several applications.
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Affiliation(s)
- Rossella Migliore
- Institute of Biomolecular Chemistry, National Research Council, Via Paolo Gaifami 18, 95126 Catania, Italy;
| | - Tarita Biver
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy;
| | - Giampaolo Barone
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, Viale delle Scienze, Edificio 17, 90128 Palermo, Italy;
| | - Carmelo Sgarlata
- Department of Chemical Sciences, University of Catania, Viale Andrea Doria 6, 95125 Catania, Italy
- Correspondence:
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Orzeł Ł, Oszajca M, Polaczek J, Porębska D, van Eldik R, Stochel G. High-Pressure Mechanistic Insight into Bioinorganic NO Chemistry. Molecules 2021; 26:molecules26164947. [PMID: 34443535 PMCID: PMC8401417 DOI: 10.3390/molecules26164947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/06/2021] [Accepted: 08/12/2021] [Indexed: 11/23/2022] Open
Abstract
Pressure is one of the most important parameters controlling the kinetics of chemical reactions. The ability to combine high-pressure techniques with time-resolved spectroscopy has provided a powerful tool in the study of reaction mechanisms. This review is focused on the supporting role of high-pressure kinetic and spectroscopic methods in the exploration of nitric oxide bioinorganic chemistry. Nitric oxide and other reactive nitrogen species (RNS) are important biological mediators involved in both physiological and pathological processes. Understanding molecular mechanisms of their interactions with redox-active metal/non-metal centers in biological targets, such as cofactors, prosthetic groups, and proteins, is crucial for the improved therapy of various diseases. The present review is an attempt to demonstrate how the application of high-pressure kinetic and spectroscopic methods can add additional information, thus enabling the mechanistic interpretation of various NO bioinorganic reactions.
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Affiliation(s)
- Łukasz Orzeł
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland; (Ł.O.); (M.O.); (J.P.); (D.P.)
| | - Maria Oszajca
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland; (Ł.O.); (M.O.); (J.P.); (D.P.)
| | - Justyna Polaczek
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland; (Ł.O.); (M.O.); (J.P.); (D.P.)
| | - Dominika Porębska
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland; (Ł.O.); (M.O.); (J.P.); (D.P.)
| | - Rudi van Eldik
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland; (Ł.O.); (M.O.); (J.P.); (D.P.)
- Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Egerlandstr 1, 91058 Erlangen, Germany
- Correspondence: (R.v.E.); (G.S.); Tel.: +48-66-777-2932 (R.v.E.); +48-12-686-2502 (G.S.)
| | - Grażyna Stochel
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland; (Ł.O.); (M.O.); (J.P.); (D.P.)
- Correspondence: (R.v.E.); (G.S.); Tel.: +48-66-777-2932 (R.v.E.); +48-12-686-2502 (G.S.)
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4
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Kálmán FK, Nagy V, Uzal-Varela R, Pérez-Lourido P, Esteban-Gómez D, Garda Z, Pota K, Mezei R, Pallier A, Tóth É, Platas-Iglesias C, Tircsó G. Expanding the Ligand Classes Used for Mn(II) Complexation: Oxa-aza Macrocycles Make the Difference. Molecules 2021; 26:molecules26061524. [PMID: 33802241 PMCID: PMC7998310 DOI: 10.3390/molecules26061524] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 02/27/2021] [Accepted: 02/28/2021] [Indexed: 12/16/2022] Open
Abstract
We report two macrocyclic ligands based on a 1,7-diaza-12-crown-4 platform functionalized with acetate (tO2DO2A2−) or piperidineacetamide (tO2DO2AMPip) pendant arms and a detailed characterization of the corresponding Mn(II) complexes. The X−ray structure of [Mn(tO2DO2A)(H2O)]·2H2O shows that the metal ion is coordinated by six donor atoms of the macrocyclic ligand and one water molecule, to result in seven-coordination. The Cu(II) analogue presents a distorted octahedral coordination environment. The protonation constants of the ligands and the stability constants of the complexes formed with Mn(II) and other biologically relevant metal ions (Mg(II), Ca(II), Cu(II) and Zn(II)) were determined using potentiometric titrations (I = 0.15 M NaCl, T = 25 °C). The conditional stabilities of Mn(II) complexes at pH 7.4 are comparable to those reported for the cyclen-based tDO2A2− ligand. The dissociation of the Mn(II) chelates were investigated by evaluating the rate constants of metal exchange reactions with Cu(II) under acidic conditions (I = 0.15 M NaCl, T = 25 °C). Dissociation of the [Mn(tO2DO2A)(H2O)] complex occurs through both proton− and metal−assisted pathways, while the [Mn(tO2DO2AMPip)(H2O)] analogue dissociates through spontaneous and proton-assisted mechanisms. The Mn(II) complex of tO2DO2A2− is remarkably inert with respect to its dissociation, while the amide analogue is significantly more labile. The presence of a water molecule coordinated to Mn(II) imparts relatively high relaxivities to the complexes. The parameters determining this key property were investigated using 17O NMR (Nuclear Magnetic Resonance) transverse relaxation rates and 1H nuclear magnetic relaxation dispersion (NMRD) profiles.
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Affiliation(s)
- Ferenc K. Kálmán
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary; (F.K.K.); (V.N.); (Z.G.); (R.M.)
| | - Viktória Nagy
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary; (F.K.K.); (V.N.); (Z.G.); (R.M.)
| | - Rocío Uzal-Varela
- Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain; (R.U.-V.); (D.E.-G.)
| | - Paulo Pérez-Lourido
- Departamento de Química Inorgánica, Facultad de Ciencias, Universidade de Vigo, As Lagoas, Marcosende, 36310 Pontevedra, Spain;
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain; (R.U.-V.); (D.E.-G.)
| | - Zoltán Garda
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary; (F.K.K.); (V.N.); (Z.G.); (R.M.)
| | - Kristof Pota
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 West Bowie Street, Fort Worth, TX 76109, USA;
| | - Roland Mezei
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary; (F.K.K.); (V.N.); (Z.G.); (R.M.)
| | - Agnès Pallier
- Centre de Biophysique Moléculaire, CNRS, UPR 4301, Rue Charles-Sadron, CEDEX 2, 45071 Orléans, France;
| | - Éva Tóth
- Centre de Biophysique Moléculaire, CNRS, UPR 4301, Rue Charles-Sadron, CEDEX 2, 45071 Orléans, France;
- Correspondence: (É.T.); (C.P.-I.); (G.T.); Tel.: +33-2-38-25-76-25 (É.T.); +34-881-5597 (C.P.-I.); +36-52-512-900 (ext. 22374) (G.T.)
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Química, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain; (R.U.-V.); (D.E.-G.)
- Correspondence: (É.T.); (C.P.-I.); (G.T.); Tel.: +33-2-38-25-76-25 (É.T.); +34-881-5597 (C.P.-I.); +36-52-512-900 (ext. 22374) (G.T.)
| | - Gyula Tircsó
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, H-4010 Debrecen, Hungary; (F.K.K.); (V.N.); (Z.G.); (R.M.)
- Correspondence: (É.T.); (C.P.-I.); (G.T.); Tel.: +33-2-38-25-76-25 (É.T.); +34-881-5597 (C.P.-I.); +36-52-512-900 (ext. 22374) (G.T.)
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5
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Porcar-Tost O, Pallier A, Esteban-Gómez D, Illa O, Platas-Iglesias C, Tóth É, Ortuño RM. Stability, relaxometric and computational studies on Mn 2+ complexes with ligands containing a cyclobutane scaffold. Dalton Trans 2021; 50:1076-1085. [PMID: 33367361 DOI: 10.1039/d0dt03402a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The stability constants of Mn2+ complexes with ligands containing a trans-1,2-cyclobutanediamine spacer functionalized with picolinate and/or carboxylate functions were determined using potentiometric titrations (25 °C, 0.1 M KCl). The stability constant of the complex with a hexadentate ligand containing four acetate groups (L14-, log KMnL = 10.26) is improved upon replacing one (L24-, log KMnL = 14.71) or two (L34-, log KMnL = 15.81) carboxylate groups with picolinates. The [Mn(L1)]2- complex contains a water molecule coordinated to the metal ion in aqueous solutions, as evidenced by 1H NMRD studies and 17O chemical shifts and transverse relaxation rates. The 1H relaxivities determined at 60 MHz (3.3 and 2.4 mM-1 s-1 at 25 and 37 °C, respectively) are comparable to those of monohydrated complexes such as [Mn(edta)]2-. The exchange rate of the inner-sphere water molecule (k = 248 × 106 s-1) is slightly lower than that of the edta4- analogue. DFT calculations (M11/def2-TZVP) suggest that the water exchange reaction follows a dissociatively activated mechanism, providing activation parameters in reasonably good agreement with the experimental data. DFT calculations also show that the 17O hyperfine coupling constant A/ℏ is affected slightly by changes in the Mn-Owater distance and the orientation of the water molecule with respect to the Mn-O vector.
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Affiliation(s)
- Oriol Porcar-Tost
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain.
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Kim Y, Yun D, Jeon J. Performance improvement of aqueous zinc-iron flow batteries through organic ligand complexation of Fe(II)/Fe(III). Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2020.136691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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7
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Pujales-Paradela R, Carniato F, Esteban-Gómez D, Botta M, Platas-Iglesias C. Controlling water exchange rates in potential Mn 2+-based MRI agents derived from NO2A 2. Dalton Trans 2019; 48:3962-3972. [PMID: 30834411 DOI: 10.1039/c9dt00211a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We report a series of pentadentate ligands based on a 1,4,7-triazacyclononane-1,4-diacetic acid (H2NO2A) containing different substituents attached to the third nitrogen atom of the macrocyclic unit. Detailed 1H Nuclear Magnetic Relaxation Dispersion (NMRD) characterisation of the corresponding Mn2+ complexes suggests the formation of six-coordinate species in solution containing an inner-sphere water molecule. This was confirmed by recording the transverse 17O relaxation time and chemical shift measurements. The water exchange rate of the coordinated water molecule was found to be strongly influenced by the nature of the substituent R at position 7 of the triazacyclononane unit (R = Me, k298ex = 62.6 × 107 s-1; R = Bz, k298ex = 4.4 × 107 s-1; R = 1-phenylethyl, k298ex = 2.6 × 107 s-1). The decreasing exchange rates are explained by the increasing bulkiness of the substituent, which hinders the approach of the entering water molecule in an associatively activated water exchange mechanism. This is supported by DFT calculations (M062X/TZVP), which confirm the associative nature of the water exchange reaction. A potentially decadentate ligand containing two NO2A units linked by a xylenyl spacer in the meta position was also synthesised. The corresponding binuclear Mn2+ complex contains two metal ions with different hydration numbers, as evidenced by 1H NMRD and 17O NMR measurements. DFT calculations show that this is related to the presence of a bridging bidentate μ-η1-carboxylate group connecting the two metal centers. The results reported in this work provide a straightforward strategy to control the exchange rate of the coordinated water molecule in this family of MRI contrast agent candidates.
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Affiliation(s)
- Rosa Pujales-Paradela
- Universidade da Coruña, Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química, Facultade de Ciencias, 15071, A Coruña, Galicia, Spain.
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8
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Caravan P, Esteban-Gómez D, Rodríguez-Rodríguez A, Platas-Iglesias C. Water exchange in lanthanide complexes for MRI applications. Lessons learned over the last 25 years. Dalton Trans 2019; 48:11161-11180. [DOI: 10.1039/c9dt01948k] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Coordination chemistry offers convenient strategies to modulate the exchange of coordinated water molecules in lanthanide-based contrast agents.
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Affiliation(s)
- Peter Caravan
- The Institute for Innovation in Imaging and the A. A. Martinos Center for Biomedical Imaging
- Massachusetts General Hospital
- Harvard Medical School
- Charlestown
- USA
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química
- Universidade da Coruña
- 15008 A Coruña
- Spain
| | - Aurora Rodríguez-Rodríguez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química
- Universidade da Coruña
- 15008 A Coruña
- Spain
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química
- Universidade da Coruña
- 15008 A Coruña
- Spain
- The Institute for Innovation in Imaging and the A. A. Martinos Center for Biomedical Imaging
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Spooner J, Wiebe H, Louwerse M, Reader B, Weinberg N. Theoretical analysis of high-pressure effects on conformational equilibria. CAN J CHEM 2018. [DOI: 10.1139/cjc-2017-0411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Along with temperature, pressure is the most important physical parameter determining the thermodynamic properties and reactivity of chemical systems. In this work, we discuss the effects of high pressure on conformational properties of organic molecules and propose an approach toward calculation of conformational volume changes based on molecular dynamics simulations. The results agree well with the experimental data. Furthermore, we demonstrate that pressure can be used as an instrument for fine-tuning of molecular conformations and to propel a properly constructed molecular rotor possessing a suitable combination of energy and volume profiles.
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Affiliation(s)
- Jacob Spooner
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Heather Wiebe
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Miranda Louwerse
- Department of Chemistry, University of the Fraser Valley, Abbotsford, BC V2S 7M8, Canada
| | - Brandon Reader
- Department of Chemistry, University of the Fraser Valley, Abbotsford, BC V2S 7M8, Canada
| | - Noham Weinberg
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Department of Chemistry, University of the Fraser Valley, Abbotsford, BC V2S 7M8, Canada
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Wiebe H, Louwerse M, Weinberg N. Theoretical volume profiles for conformational changes: Application to internal rotation of benzene ring in 1,12-dimethoxy-[12]-paracyclophane. J Chem Phys 2017; 146:104107. [DOI: 10.1063/1.4977732] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Heather Wiebe
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Miranda Louwerse
- Department of Chemistry, University of the Fraser Valley, Abbotsford, British Columbia V2S 7M8, Canada
| | - Noham Weinberg
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
- Department of Chemistry, University of the Fraser Valley, Abbotsford, British Columbia V2S 7M8, Canada
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Mambanda A, Jaganyi D. Controlling the Lability of Square-Planar Pt(II) Complexes Through Electronic and π-Conjugation: Correlation Between Kinetics and Theoretical Parameters. ADVANCES IN INORGANIC CHEMISTRY 2017. [DOI: 10.1016/bs.adioch.2017.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Spooner J, Smith B, Weinberg N. Effect of high pressure on the topography of potential energy surfaces. CAN J CHEM 2016. [DOI: 10.1139/cjc-2016-0295] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Properties and reactivity of chemical compounds change dramatically at elevated pressures. Since kinetics and mechanisms of condensed-phase reactions are described in terms of their potential energy (PESs) or Gibbs energy (GESs) surfaces, chemical effects of high pressure can be assessed through analysis of pressure-induced deformations of GESs of solvated reaction systems. We discuss general trends expected for such changes and use quantum mechanical calculations to construct PESs of compressed species for hydrogen and methyl transfer reactions.
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Affiliation(s)
- Jacob Spooner
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Brandon Smith
- Department of Chemistry, University College of the Fraser Valley, Abbotsford, BC V2S 7M8, Canada
| | - Noham Weinberg
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Department of Chemistry, University College of the Fraser Valley, Abbotsford, BC V2S 7M8, Canada
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Schmeisser M, van Eldik R. Elucidation of inorganic reaction mechanisms in ionic liquids: the important role of solvent donor and acceptor properties. Dalton Trans 2014; 43:15675-92. [PMID: 25043340 DOI: 10.1039/c4dt01239a] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this article, we focus on the important role of solvent donor and acceptor properties of ionic liquids in the elucidation of inorganic reaction mechanisms. For this purpose, mechanistic and structural studies on typical inorganic reactions, performed in ionic liquids, have been conducted. The presented systems range from simple complex-formation and ligand-substitution reactions to the activation of small molecules by catalytically active complexes. The data obtained for the reactions in ionic liquids are compared with those for the same reactions carried out in conventional solvents, and are discussed with respect to the donor and acceptor properties of the applied ionic liquids. The intention of this perspective is to gain more insight into the role of ILs as solvents and their interaction with metal ions and complexes in solution.
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Affiliation(s)
- Matthias Schmeisser
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Egerlandstr. 1, 91058 Erlangen, Germany.
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Troeppner O, Lippert R, Shubina TE, Zahl A, Jux N, Ivanović-Burmazović I. Reverse Spin-Crossover and High-Pressure Kinetics of the Heme Iron Center Relevant for the Operation of Heme Proteins under Deep-Sea Conditions. Angew Chem Int Ed Engl 2014; 53:11452-7. [DOI: 10.1002/anie.201406954] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Indexed: 11/06/2022]
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15
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Troeppner O, Lippert R, Shubina TE, Zahl A, Jux N, Ivanović-Burmazović I. Reverse Spin-Crossover and High-Pressure Kinetics of the Heme Iron Center Relevant for the Operation of Heme Proteins under Deep-Sea Conditions. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201406954] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Radical decomposition of hydrogen peroxide catalyzed by aqua complexes [M(H2O)n]2+ (M=Be, Zn, Cd). J Catal 2014. [DOI: 10.1016/j.jcat.2014.03.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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17
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Wiebe H, Weinberg N. Theoretical volume profiles as a tool for probing transition states: folding kinetics. J Chem Phys 2014; 140:124105. [PMID: 24697422 DOI: 10.1063/1.4868549] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The mechanism by which conformational changes, particularly folding and unfolding, occur in proteins and other biopolymers has been widely discussed in the literature. Molecular dynamics (MD) simulations of protein folding present a formidable challenge since these conformational changes occur on a time scale much longer than what can be afforded at the current level of computational technology. Transition state (TS) theory offers a more economic description of kinetic properties of a reaction system by relating them to the properties of the TS, or for flexible systems, the TS ensemble (TSE). The application of TS theory to protein folding is limited by ambiguity in the definition of the TSE for this process. We propose to identify the TSE for conformational changes in flexible systems by comparison of its experimentally determined volumetric property, known as the volume of activation, to the structure-specific volume profile of the process calculated using MD. We illustrate this approach by its successful application to unfolding of a model chain system.
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Affiliation(s)
- H Wiebe
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - N Weinberg
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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Spooner J, Yanciw B, Wiebe B, Weinberg N. Reaction Profiles and Energy Surfaces of Compressed Species. J Phys Chem A 2014; 118:765-77. [DOI: 10.1021/jp410496t] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jacob Spooner
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Brandon Yanciw
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Brandon Wiebe
- Department of Chemistry, University of the Fraser Valley, Abbotsford, BC V2S 7M8, Canada
| | - Noham Weinberg
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- Department of Chemistry, University of the Fraser Valley, Abbotsford, BC V2S 7M8, Canada
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Troeppner O, Huang D, Holm RH, Ivanović-Burmazović I. Thermodynamics and high-pressure kinetics of a fast carbon dioxide fixation reaction by a (2,6-pyridinedicarboxamidato-hydroxo)nickel(ii) complex. Dalton Trans 2014; 43:5274-9. [DOI: 10.1039/c3dt53004c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The thermodynamics and high-pressure kinetics of the fastest CO2 fixation reaction by a metal-bound hydroxide resulted in a clear mechanistic picture and characterization of a very compact five-coordinate transition state.
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Affiliation(s)
- O Troeppner
- Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Egerlandstr. 1, 91058, Erlangen, Germany.
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Walther M, Budimir A, Puchta R. Water exchange on beryllium complexes: part VIII – influence of neutral electron pair donors. J COORD CHEM 2012. [DOI: 10.1080/00958972.2012.739284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Markus Walther
- a Department of Chemistry and Pharmacy , University of Erlangen-Nürnberg – Egerlandstraße 1 – 91058 Erlangen , Germany
- b Department of Chemistry and Pharmacy, Computer Chemistry Center , University of Erlangen-Nürnberg , Nägelsbachstr. 25, 91052 Erlangen , Germany
| | - Ana Budimir
- c Faculty of Pharmacy and Biochemistry , University of Zagreb , A. Kovačića 1 – 10000 Zagreb , Croatia
| | - Ralph Puchta
- a Department of Chemistry and Pharmacy , University of Erlangen-Nürnberg – Egerlandstraße 1 – 91058 Erlangen , Germany
- b Department of Chemistry and Pharmacy, Computer Chemistry Center , University of Erlangen-Nürnberg , Nägelsbachstr. 25, 91052 Erlangen , Germany
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Kern S, van Eldik R. Mechanistic Insight from Activation Parameters for the Reaction of a Ruthenium Hydride Complex with CO2 in Conventional Solvents and an Ionic Liquid. Inorg Chem 2012; 51:7340-5. [DOI: 10.1021/ic300718v] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Simon Kern
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University Erlangen-Nuremberg, Egerlandstr. 1, 91058
Erlangen, Germany
| | - Rudi van Eldik
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University Erlangen-Nuremberg, Egerlandstr. 1, 91058
Erlangen, Germany
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Panasci AF, Ohlin CA, Harley SJ, Casey WH. Rates of Water Exchange on the [Fe4(OH)2(hpdta)2(H2O)4]0 Molecule and Its Implications for Geochemistry. Inorg Chem 2012; 51:6731-8. [DOI: 10.1021/ic300370q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - C. André Ohlin
- School of Chemistry, Monash University, Victoria, 3800 Australia
| | - Stephen J. Harley
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue,
Livermore, California 94550-9698, United States
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Wiśniewska J, Wrzeszcz G, Kurzawa M, van Eldik R. The oxidative degradation of dibenzoazepine derivatives by cerium(iv) complexes in acidic sulfate media. Dalton Trans 2012; 41:1259-67. [DOI: 10.1039/c1dt11664a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Budimir A, Walther M, Puchta R, van Eldik R. Ligand Exchange Processes on Solvated Beryllium Cations V. Water Exchange on [Be(X)(H2O)3]+ (X: H-,F-, Cl-, Br-, OH-, CN-, NCNCN-)‡. Z Anorg Allg Chem 2011. [DOI: 10.1002/zaac.201000418] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Stasicka Z. Transition metal complexes as solar photocatalysts in the environment. ADVANCES IN INORGANIC CHEMISTRY 2011. [DOI: 10.1016/b978-0-12-385904-4.00004-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Popescu DL, Vrabel M, Brausam A, Madsen P, Lente G, Fabian I, Ryabov AD, van Eldik R, Collins TJ. Thermodynamic, electrochemical, high-pressure kinetic, and mechanistic studies of the formation of oxo Fe(IV)-TAML species in water. Inorg Chem 2010; 49:11439-48. [PMID: 21086984 DOI: 10.1021/ic1015109] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Stopped-flow kinetic studies of the oxidation of Fe(III)-TAML catalysts, [ F e{1,2-X(2)C(6)H(2)-4,5-( NCOCMe(2) NCO)(2)CMe(2)}(OH(2))](-) (1), by t-BuOOH and H(2)O(2) in water affording Fe(IV) species has helped to clarify the mechanism of the interaction of 1 with primary oxidants. The data collected for substituted Fe(III)-TAMLs at pH 6.0-13.8 and 17-45 °C has confirmed that the reaction is first order both in 1 and in peroxides. Bell-shaped pH profiles of the effective second-order rate constants k(I) have maximum values in the pH range of 10.5-12.5 depending on the nature of 1 and the selected peroxide. The "acidic" part is governed by the deprotonation of the diaqua form of 1 and therefore electron-withdrawing groups move the lower pH limit of the reactivity toward neutral pH, although the rate constants k(I) do not change much. The dissection of k(I) into individual intrinsic rate constants k(1) ([FeL(OH(2))(2)](-) + ROOH), k(2) ([FeL(OH(2))OH)](2-) + ROOH), k(3) ([FeL(OH(2))(2)](-) + ROO(-)), and k(4) ([FeL(OH(2))OH)](2-) + ROO(-)) provides a model for understanding the bell-shaped pH-profiles. Analysis of the pressure and substituent effects on the reaction kinetics suggest that the k(2) pathway is (i) more probable than the kinetically indistinguishable k(3) pathway, and (ii) presumably mechanistically similar to the induced cleavage of the peroxide O-O bond postulated for cytochrome P450 enzymes. The redox titration of 1 by Ir(IV) and electrochemical data suggest that under basic conditions the reduction potential for the half-reaction [Fe(IV)L(=O)(OH(2))](2-) + e(-) + H(2)O → [Fe(III)L(OH)(OH(2))](2-) + OH(-) is close to 0.87 V (vs NHE).
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Affiliation(s)
- Delia-Laura Popescu
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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Qian Z, Feng H, Wang C, Chen J. Theoretical investigation of the dissociative interchange (Id) mechanism for water exchange on magnesium(II) in aqueous solution. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2010.06.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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