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Santra B, Narayanan RS, Kalita P, Kumar V, Mandal D, Gupta V, Zimmer M, Huch V, Chandrasekhar V, Scheschkewitz D, Schulzke C, Jana A. Modulation of the nuclearity of molecular Mg(ii)-phosphates: solid-state structural change involving coordinating solvents. Dalton Trans 2019; 48:8853-8860. [PMID: 31139786 DOI: 10.1039/c9dt00687g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Herein, we report the synthesis and molecular structures of various magnesium(ii)-phosphate monoesters. By using a bulky aryl substituted phosphate monoester, ArOPO3H2 (Ar = 2,6-(CHPh2)2-4-tBu-C6H2), we have reproducibly assembled mono-, di-, tetra- (cage and ring), hexa-, and polynuclear magnesium(ii)-phosphate monoesters. Interestingly, the hexanuclear magnesium(ii)-phosphate monoester encapsulates an open-cage dodecanuclear water cluster.
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Affiliation(s)
- Biswajit Santra
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India.
| | | | - Pankaj Kalita
- School of Chemical Sciences, National Institute of Science Education and Research, HBNI, Bhubaneswar-752050, India
| | - Vierandra Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Debdeep Mandal
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India.
| | - Vivek Gupta
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India.
| | - Michael Zimmer
- Krupp-Chair of General and Inorganic Chemistry, Saarland University, 66123 Saarbrücken, Germany.
| | - Volker Huch
- Krupp-Chair of General and Inorganic Chemistry, Saarland University, 66123 Saarbrücken, Germany.
| | - Vadapalli Chandrasekhar
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India. and Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - David Scheschkewitz
- Krupp-Chair of General and Inorganic Chemistry, Saarland University, 66123 Saarbrücken, Germany.
| | - Carola Schulzke
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Straße 4, D-17487, Greifswald, Germany.
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad, Gopanpally, Hyderabad-500107, Telangana, India.
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Itoh S, Kawakami H, Fukuzumi S. Model studies on calcium-containing quinoprotein alcohol dehydrogenases. Catalytic role of Ca2+ for the oxidation of alcohols by coenzyme PQQ (4,5-dihydro-4,5-dioxo-1H-pyrrolo[2,3-f]quinoline-2, 7,9-tricarboxylic acid). Biochemistry 1998; 37:6562-71. [PMID: 9572874 DOI: 10.1021/bi9800092] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mechanistic studies on the action of calcium-containing quinoprotein alcohol dehydrogenases have been performed by using a series of PQQ model compounds in anhydrous organic media. The PQQ model compounds are shown to form 1:1 complexes with a series of alkaline earth metal ions by spectroscopic methods and theoretical calculations. The site of coordination of the PQQ molecule to the metal ions in solution is indicated to be the same as in the case of enzymatic systems. It has also been found that Ca2+ binds to the quinone most strongly among the alkaline earth metal ions. Formation of the C-5 hemiacetal derivatives with methanol, ethanol, and 2-propanol is also investigated spectrophotometrically to show that the alcohol addition to the quinone is enhanced in the presence of the metal ions. In this case as well, Ca2+ shows the highest efficiency for the enhancement of the C-5 hemiacetal formation. Addition of a strong base such as DBU into an MeCN solution containing the Ca2+ complex of the PQQ model compounds and the alcohols leads to the redox reactions to afford reduced PQQ derivatives and the corresponding aldehydes. On the basis of detailed kinetic studies on the redox reactions, including structural effects of PQQ analogues and metal ion effects, we propose the addition-oxidative elimination mechanism through the C-5 hemiacetal intermediate.
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Affiliation(s)
- S Itoh
- Department of Applied Chemistry, Faculty of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
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