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Knasin AL, Schelter EJ. Synthetic modeling of the structure and function of the rare-earth dependent methanol dehydrogenase cofactor. Methods Enzymol 2021; 650:19-55. [PMID: 33867022 DOI: 10.1016/bs.mie.2021.01.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Historically, rare-earth ions have been considered irrelevant to biology. Recently, the active sites of certain methanol dehydrogenase (MDH) enzymes have been shown to contain a redox-inactive, rare-earth (RE) cation coordinated by the redox-active pyrroloquinoline quinone (PQQ) cofactor. Importantly, it was demonstrated that rare earths were essential for the growth of certain methylotrophs that incorporated the XoxF-MDH. In this chapter, we summarize the optimized synthesis of a previously published rare-earth complex that serves as a model of the active site of this RE-containing MDH enzyme. The structure and reactivity of the metalated complex, [La(LQQ)(NO3)3] are also discussed. [La(LQQ)(NO3)3] catalytically oxidizes the test alcohol substrate, p-methylbenzyl alcohol, 4MeBnOH, to p-methylbenzaldehyde, 4MePhCHO, in the presence of a base (2,6-lutidine) and a terminal oxidant (ferrocenium hexafluorophosphate) with ~17 turnovers. By studying this synthetic model, we have developed a body of evidence about both the reactivity and the mechanism of dehydrogenation of alcohols as a molecular analogue to a native, rare-earth dependent enzyme.
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Affiliation(s)
- Alison L Knasin
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA, United States
| | - Eric J Schelter
- P. Roy and Diana T. Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA, United States.
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2
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Lumpe H, Mayer P, Daumann LJ. Crystal structure of a calcium(II)-pyrroloquinoline quinone (PQQ) complex outside a protein environment. Acta Crystallogr C Struct Chem 2020; 76:1051-1056. [PMID: 33273141 PMCID: PMC7716187 DOI: 10.1107/s2053229620014278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 10/27/2020] [Indexed: 11/24/2022] Open
Abstract
Pyrroloquinoline quinone (PQQ) is an important cofactor of calcium- and lanthanide-dependent alcohol dehydrogenases, and has been known for over 30 years. Crystal structures of Ca-MDH enzymes (MDH is methanol dehydrogenase) have been known for some time; however, crystal structures of PQQ with biorelevant metal ions have been lacking in the literature for decades. We report here the first crystal structure analysis of a Ca-PQQ complex outside the protein environment, namely, poly[[undecaaquabis(μ-4,5-dioxo-4,5-dihydro-1H-pyrrolo[2,3-f]quinoline-2,7,9-tricarboxylato)tricalcium(II)] dihydrate], {[Ca3(C14H3N2O8)2(H2O)11]·2H2O}n. The complex crystallized as Ca3PQQ2·13H2O with Ca2+ in three different positions and PQQ3-, including an extensive hydrogen-bond network. Similarities and differences to the recently reported structure with biorelevant europium (Eu2PQQ2) are discussed.
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Affiliation(s)
- Henning Lumpe
- Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Munich, Bavaria 81377, Germany
| | - Peter Mayer
- Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Munich, Bavaria 81377, Germany
| | - Lena J. Daumann
- Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Munich, Bavaria 81377, Germany
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Lumpe H, Menke A, Haisch C, Mayer P, Kabelitz A, Yusenko KV, Guilherme Buzanich A, Block T, Pöttgen R, Emmerling F, Daumann LJ. The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone. Chemistry 2020; 26:10133-10139. [PMID: 32497263 PMCID: PMC7496819 DOI: 10.1002/chem.202002653] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Indexed: 12/18/2022]
Abstract
Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment. The complex crystallizes as an inversion symmetric dimer, Eu2 PQQ2 , with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled plasma mass spectrometry (ICP-MS), infrared (IR) spectroscopy, 151 Eu-Mössbauer spectroscopy, X-ray total scattering, and extended X-ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
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Affiliation(s)
- Henning Lumpe
- Department of ChemistryLudwig-Maximilians-University MunichButenandtstraße 5–1381377MünchenGermany
| | - Annika Menke
- Department of ChemistryLudwig-Maximilians-University MunichButenandtstraße 5–1381377MünchenGermany
| | - Christoph Haisch
- Chair of Analytical Chemistry and Water ChemistryTechnical University of MunichMarchioninistraße 1781377MünchenGermany
| | - Peter Mayer
- Department of ChemistryLudwig-Maximilians-University MunichButenandtstraße 5–1381377MünchenGermany
| | - Anke Kabelitz
- Division Structure AnalysisFederal Institute for Materials Research and Testing (BAM)Richard-Willstätter-Straße 1112489BerlinGermany
| | - Kirill V. Yusenko
- Division Structure AnalysisFederal Institute for Materials Research and Testing (BAM)Richard-Willstätter-Straße 1112489BerlinGermany
| | - Ana Guilherme Buzanich
- Division Structure AnalysisFederal Institute for Materials Research and Testing (BAM)Richard-Willstätter-Straße 1112489BerlinGermany
| | - Theresa Block
- Institut für Anorganische und Analytische ChemieUniversität Münster (WWU)Corrensstraße 3048149MünsterGermany
| | - Rainer Pöttgen
- Institut für Anorganische und Analytische ChemieUniversität Münster (WWU)Corrensstraße 3048149MünsterGermany
| | - Franziska Emmerling
- Division Structure AnalysisFederal Institute for Materials Research and Testing (BAM)Richard-Willstätter-Straße 1112489BerlinGermany
| | - Lena J. Daumann
- Department of ChemistryLudwig-Maximilians-University MunichButenandtstraße 5–1381377MünchenGermany
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Lumpe H, Daumann LJ. Studies of Redox Cofactor Pyrroloquinoline Quinone and Its Interaction with Lanthanides(III) and Calcium(II). Inorg Chem 2019; 58:8432-8441. [DOI: 10.1021/acs.inorgchem.9b00568] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Henning Lumpe
- Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany
| | - Lena J. Daumann
- Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 Munich, Germany
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5
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McSkimming A, Cheisson T, Carroll PJ, Schelter EJ. Functional Synthetic Model for the Lanthanide-Dependent Quinoid Alcohol Dehydrogenase Active Site. J Am Chem Soc 2018; 140:1223-1226. [DOI: 10.1021/jacs.7b12318] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Alex McSkimming
- P. Roy and Diana T. Vagelos
Laboratories, Department of Chemistry, University of Pennsylvania, 231 S 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Thibault Cheisson
- P. Roy and Diana T. Vagelos
Laboratories, Department of Chemistry, University of Pennsylvania, 231 S 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Patrick J. Carroll
- P. Roy and Diana T. Vagelos
Laboratories, Department of Chemistry, University of Pennsylvania, 231 S 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Eric J. Schelter
- P. Roy and Diana T. Vagelos
Laboratories, Department of Chemistry, University of Pennsylvania, 231 S 34th Street, Philadelphia, Pennsylvania 19104, United States
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Mitome H, Ishizuka T, Shiota Y, Yoshizawa K, Kojima T. Controlling the redox properties of a pyrroloquinolinequinone (PQQ) derivative in a ruthenium(ii) coordination sphere. Dalton Trans 2015; 44:3151-8. [DOI: 10.1039/c4dt03358b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Difference in the coordination modes of pyrroloquinolinequinone (PQQ), a redox-active heteroaromatic cofactor, in ruthenium(ii) complexes, drastically affects the stability of the metal coordination and the reversibility of the reduction process of the PQQ ligand. Additional metal-ion binding to the PQQ ligand largely raises its 1e−-reduction potential.
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Affiliation(s)
- Hiroumi Mitome
- Department of Chemistry
- University of Tsukuba
- Tsukuba
- Japan
| | | | - Yoshihito Shiota
- Institute for Materials Chemistry and Engineering and International Research Centre for Molecular System
- Kyushu University
- Nishi-Ku
- Japan
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering and International Research Centre for Molecular System
- Kyushu University
- Nishi-Ku
- Japan
- Elements Strategy Initiative for Catalysts & Batteries
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Jana R, Lissner F, Kaim W. Coordinative Saturation of the Pterin Heterocycle by Ferrocenylcopper(I) Complex Fragments. Z Anorg Allg Chem 2014. [DOI: 10.1002/zaac.201400529] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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8
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Mitome H, Ishizuka T, Shiota Y, Yoshizawa K, Kojima T. Heteronuclear RuIIAgI Complexes Having a Pyrroloquinolinequinone Derivative as a Bridging Ligand. Inorg Chem 2013; 52:2274-6. [DOI: 10.1021/ic302617b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hiroumi Mitome
- Department of Chemistry, University of Tsukuba, 1-1-1 Tennoudai,
Tsukuba, Ibaraki 305-8571, Japan
| | - Tomoya Ishizuka
- Department of Chemistry, University of Tsukuba, 1-1-1 Tennoudai,
Tsukuba, Ibaraki 305-8571, Japan
| | - Yoshihiko Shiota
- Institute for Materials Chemistry and Engineering, Kyushu University, Motooka, Nishi-Ku,
Fukuoka 819-0395, Japan
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering, Kyushu University, Motooka, Nishi-Ku,
Fukuoka 819-0395, Japan
| | - Takahiko Kojima
- Department of Chemistry, University of Tsukuba, 1-1-1 Tennoudai,
Tsukuba, Ibaraki 305-8571, Japan
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Wang L, Guo B, Li HX, Li Q, Li HY, Lang JP. Polynuclear copper(ii) pyrazolate complexes: temperature-dependent protonolysis reactions, crystal structures and high catalytic activity toward the condensation of nitriles with 2-aminoalcohol. Dalton Trans 2013; 42:15570-80. [DOI: 10.1039/c3dt51970h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Ling Wang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, People's Republic of China.
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VanEngelen MR, Szilagyi RK, Gerlach R, Lee BD, Apel WA, Peyton BM. Uranium exerts acute toxicity by binding to pyrroloquinoline quinone cofactor. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:937-942. [PMID: 21166389 DOI: 10.1021/es101754x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Uranium as an environmental contaminant has been shown to be toxic to eukaryotes and prokaryotes; however, no specific mechanisms of uranium toxicity have been proposed so far. Here a combination of in vivo, in vitro, and in silico studies are presented describing direct inhibition of pyrroloquinoline quinone (PQQ)-dependent growth and metabolism by uranyl cations. Electrospray-ionization mass spectroscopy, UV-vis optical spectroscopy, competitive Ca(2+)/uranyl binding studies, relevant crystal structures, and molecular modeling unequivocally indicate the preferred binding of uranyl simultaneously to the carboxyl oxygen, pyridine nitrogen, and quinone oxygen of the PQQ molecule. The observed toxicity patterns are consistent with the biotic ligand model of acute metal toxicity. In addition to the environmental implications, this work represents the first proposed molecular mechanism of uranium toxicity in bacteria, and has relevance for uranium toxicity in many living systems.
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Affiliation(s)
- Michael R VanEngelen
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, Montana 59717-3920, United States
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11
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Hueso-Ureña F, Illán-Cabeza NA, Jiménez-Pulido SB, Moreno-Carretero MN. (6-Acetyl-1,3,7-trimethyllumazine-κ3O4,N5,O6)bis(triphenylphosphine-κP)copper(I) hexafluoridophosphate. Acta Crystallogr Sect E Struct Rep Online 2010; 66:m145-6. [PMID: 21579625 PMCID: PMC2979902 DOI: 10.1107/s1600536810000735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 01/06/2010] [Indexed: 11/10/2022]
Abstract
The title compound, [Cu(C11H12N4O3)(C18H15P)2]PF6, is the third example reported in the literature of a five-coordinated CuIP2NO2 system. The metal is coordinated to both PPh3 molecules through the P atoms and to the pyrazine ring of the lumazine molecule through an N atom in a trigonal–planar arrangement; two additional coordinated O atoms, at Cu—O distances longer than 2.46 Å, complete the coordination. The coordination environment can be described as an intermediate square-pyramidal/trigonal–bipyramidal (SP/TBP) polyhedron.
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Fukuzumi S. Roles of Metal Ions in Controlling Bioinspired Electron-Transfer Systems. Metal Ion-Coupled Electron Transfer. PROGRESS IN INORGANIC CHEMISTRY 2009. [DOI: 10.1002/9780470440124.ch2] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Yuasa J, Yamada S, Fukuzumi S. Accelerating and Decelerating Effects of Metal Ions on Electron-Transfer Reduction of Quinones as a Function of Temperature and Binding Modes of Metal Ions to Semiquinone Radical Anions. Chemistry 2008; 14:1866-74. [DOI: 10.1002/chem.200701420] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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14
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Hueso-Ureña F, Jiménez-Pulido SB, Fernández-Liencres MP, Fernández-Gómez M, Moreno-Carretero MN. A new five-coordinated CuIP2NO2 system: XRD structure of 6-acetyl-1,3,7-trimethyl-pteridine-2,4(1H,3H)-dione and its Cu(i) (N5,O61,O4)-tridentate complex with triphenylphosphine. An AIM study of the nature of metal–ligand bonds. Dalton Trans 2008:6461-6. [DOI: 10.1039/b807634k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yuasa J, Fukuzumi S. OFF−OFF−ON Switching of Fluorescence and Electron Transfer Depending on Stepwise Complex Formation of a Host Ligand with Guest Metal Ions. J Am Chem Soc 2007; 130:566-75. [DOI: 10.1021/ja0748480] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Junpei Yuasa
- Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan
| | - Shunichi Fukuzumi
- Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan
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Yuasa J, Suenobu T, Fukuzumi S. Binding modes in metal ion complexes of quinones and semiquinone radical anions: electron-transfer reactivity. Chemphyschem 2007; 7:942-54. [PMID: 16521156 DOI: 10.1002/cphc.200500640] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
9,10-Phenanthrenequinone (PQ) and 1,10-phenanthroline-5,6-dione (PTQ) form 1:1 and 2:1 complexes with metal ions (M (n+)=Sc (3+), Y (3+), Mg (2+), and Ca (2+)) in acetonitrile (MeCN), respectively. The binding constants of PQ--M (n+) complexes vary depending on either the Lewis acidity or ion radius of metal ions. The one-electron reduced species (PTQ(-)) forms 1:1 complexes with M (n+), and PQ(-) also forms 1:1 complexes with Sc(3+), Mg(2+), and Ca(2+), whereas PQ(-) forms 1:2 complexes with Y(3+) and La(3+), as indicated by electron spin resonance (ESR) measurements. On the other hand, semiquinone radical anions (Q(-) and NQ(-)) derived from p-benzoquinone (Q) and 1,4-naphthoquinone (NQ) form Sc(3+)-bridged pi-dimer radical anion complexes, Q(-)--(Sc(3+))(n)--Q and NQ(-)--(Sc(3+))(n)-NQ (n=2 and 3), respectively. The one-electron reduction potentials of quinones (PQ, PTQ, and Q) are largely positively shifted in the presence of M (n+). The rate constant of electron transfer from CoTPP (TPP(2-)=dianion of tetraphenylporphyrin) to PQ increases with increasing the concentration of Sc(3+) to reach a constant value, when all PQ molecules form the 1:1 complex with Sc(3+). Rates of electron transfer from 10,10'-dimethyl-9,9'-biacridine [(AcrH)(2)] to PTQ are also accelerated significantly by the presence of Sc(3+), Y(3+), and Mg(2+), exhibiting a first-order dependence with respect to concentrations of metal ions. In contrast to the case of o-quinones, unusually high kinetic orders are observed for rates of Sc(3+)-promoted electron transfer from tris(2-phenylpyridine)iridium(III) [Ir(ppy)(3)] to p-quinones (Q): second-order dependence on concentration of Q, and second- and third-order dependence on concentration of Sc(3+) due to formation of highly ordered radical anion complexes, Q()--(Sc(3+))(n)--Q (n=2 and 3).
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Affiliation(s)
- Junpei Yuasa
- Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, SORST, Japan
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Dimitrijevic NM, Poluektov OG, Saponjic ZV, Rajh T. Complex and Charge Transfer between TiO2 and Pyrroloquinoline Quinone. J Phys Chem B 2006; 110:25392-8. [PMID: 17165986 DOI: 10.1021/jp064469d] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pyrroloquinoline quinone (PQQ) forms a tridentate complex with coordinatively unsaturated titanium atoms on the surface of approximately 4.5 nm TiO2 particles; an association constant of K = 550 M-1 per Ti(IV)surf has been determined. Low-temperature electron paramagnetic resonance was employed in identification of localized charges and consequently produced radicals and in determination of charge-transfer processes. The photoexcitation of the PQQ-TiO2 complex results in the transfer of conduction band electrons from TiO2 to bound PQQ and the formation of the semiquinone radical. Attaching dopamine (DA) as an electron donor and PQQ as an electron acceptor on the surface of TiO2 results in spatial separation of photogenerated charges; the holes localize on dopamine and electrons on PQQ, with higher yields than for each component separately. In this triad-type assembly (PQQ-TiO2/DA) the PQQ that is bound to the particles acts as a sink for electrons allowing their almost complete scavenging even at temperature as low as 4 K.
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Affiliation(s)
- Nada M Dimitrijevic
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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18
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Kapoor P, Pathak A, Kapoor R, Venugopalan P, Corbella M, Rodríguez M, Robles J, Llobet A. Structural, electronic, and magnetic consequences of O-carbonyl vs O-alkoxy ester coordination in new dicopper complexes containing the Cu2(mu-Cl)2 core. Inorg Chem 2002; 41:6153-60. [PMID: 12425646 DOI: 10.1021/ic025568i] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The complexes [Cu2(mu-Cl)2(Cl)2(L)2] (L = dialkylpyridine-2,6-dicarboxylate; R = Et, L = depc, 1; R = i-Pr, L = dppc, 2) have been prepared and their magnetic properties studied. The crystal structures of complexes 1 and 2 have been solved. Compound 1 belongs to the P space group with Z = 2, a = 8.3020(10) A, b = 9.2050(10) A, c = 10.065(2) A, alpha = 99.040(10), beta = 100.810(10), and gamma = 106.502(10) whereas 2 belongs to the C2/c space group with Z = 8, a = 11.6360(10) A, b = 25.906(3) A, c = 11.76579(10) A, and beta = 107.900(10). The different alkyl ester substitutes produce substantial structural and electronic differences. The Cu2Cl2 core geometry is planar for 1 whereas it adopts a butterfly shape in the case of 2. Furthermore, in 2 the dppc ligand coordinates only by the carbonyl oxygen atoms whereas in 1 the depc ligand coordinates through carbonyl and alkoxy oxygen atoms. Magnetic susceptibility data show a ferromagnetic coupling between the two Cu(II) centers in both cases (J = 39.9(6) cm(-1) for 1, and J = 51.3(5) cm(-1) for 2) with very weak antiferromagnetic interactions (J ' = -0.59 cm(-1) and -0.57 cm(-1) for 1 and 2, respectively). Theoretical calculations at the extended Hückel level have also been carried out to further understand the electronic nature of complexes 1 and 2.
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Affiliation(s)
- Pratibha Kapoor
- Department of Chemistry, Panjab University, Chandigarh 160 014, India.
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Kaim W, Wanner M, Knödler A, Záliš S. Copper complexes with non-innocent ligands: probing CuII/catecholato-CuI/o-semiquinonato redox isomer equilibria with EPR spectroscopy. Inorganica Chim Acta 2002. [DOI: 10.1016/s0020-1693(02)01081-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Copper(I) complexes with N,O-donor Schiff base ligands related to intermediate forms of the TPQ cofactor in amine oxidases. Inorganica Chim Acta 2000. [DOI: 10.1016/s0020-1693(99)00612-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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