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Nazish M, Legendre CM, Ding Y, Schluschaß B, Schwederski B, Herbst-Irmer R, Parvathy P, Parameswaran P, Stalke D, Kaim W, Roesky HW. A Neutral Borylene and its Conversion to a Radical by Selective Hydrogen Transfer. Inorg Chem 2023. [PMID: 37294916 DOI: 10.1021/acs.inorgchem.3c00211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A successful selective reduction of X2B-Tip (Tip = 1,3,5-iPr3-C6H2, X = I, Br) with KC8 and Mg metal, respectively, in the presence of a hybrid ligand (C6H4(PPh2)LSi) leads to a stable low-valent five-membered ring as a boryl radical [C6H4(PPh2)LSiBTip][Br] (1) and neutral borylene [C6H4(PPh2)LSiBTip] (2). Compound 2 reacts with 1,4-cyclohexadiene, resulting in hydrogen abstraction to afford the radical [C6H4(PPh2)LSiB(H)Tip] (3). Quantum chemical studies reveal that compound 1 is a B-centered radical, and compound 2 is a phosphane and silylene stabilized neutral borylene in a trigonal planar environment, whereas compound 3 is an amidinate-centered radical. Although compounds 1 and 2 are stabilized by hyperconjugation and π-conjugation, they display high H-abstraction energy and basicity, respectively.
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Affiliation(s)
- Mohd Nazish
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Christina M Legendre
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Yi Ding
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Bastian Schluschaß
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Brigitte Schwederski
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Regine Herbst-Irmer
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Parameswaran Parvathy
- Department of Chemistry, National Institute of Technology Calicut, Kerala 673601, India
| | - Pattiyil Parameswaran
- Department of Chemistry, National Institute of Technology Calicut, Kerala 673601, India
| | - Dietmar Stalke
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Wolfgang Kaim
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Herbert W Roesky
- Universität Göttingen, Institut für Anorganische Chemie, Tammannstrasse 4, 37077 Göttingen, Germany
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Ehret F, Filippou V, Blickle S, Bubrin M, Záliš S, Kaim W. Structural and Oxidation State Alternatives in Platinum and Palladium Complexes of a Redox-Active Amidinato Ligand. Chemistry 2021; 27:3374-3381. [PMID: 32959415 PMCID: PMC7986709 DOI: 10.1002/chem.202003636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Indexed: 11/07/2022]
Abstract
Reaction of [Pt(DMSO)2 Cl2 ] or [Pd(MeCN)2 Cl2 ] with the electron-rich LH=N,N'-bis(4-dimethylaminophenyl)ethanimidamide yielded mononuclear [PtL2 ] (1) but dinuclear [Pd2 L4 ] (2), a paddle-wheel complex. The neutral compounds were characterized through experiments (crystal structures, electrochemistry, UV-vis-NIR spectroscopy, magnetic resonance) and TD-DFT calculations as metal(II) species with noninnocent ligands L- . The reversibly accessible cations [PtL2 ]+ and [Pd2 L4 ]+ were also studied, the latter as [Pd2 L4 ][B{3,5-(CF3 )2 C6 H3 }4 ] single crystals. Experimental and computational investigations were directed at the elucidation of the electronic structures, establishing the correct oxidation states within the alternatives [PtII (L- )2 ] or [Pt. (L )2 ], [PtII (L0.5- )2 ]+ or [PtIII (L- )2 ]+ , [(PdII )2 (μ-L- )4 ] or [(Pd1.5 )2 (μ-L0.75- )4 ], and [(Pd2.5 )2 (μ-L- )4 ]+ or [(PdII )2 (μ-L0.75- )4 ]+ . In each case, the first alternative was shown to be most appropriate. Remarkable results include the preference of platinum for mononuclear planar [PtL2 ] with an N-Pt-N bite angle of 62.8(2)° in contrast to [Pd2 L4 ], and the dimetal (Pd2 4+ →Pd2 5+ ) instead of ligand (L- →L ) oxidation of the dinuclear palladium compound.
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Affiliation(s)
- Fabian Ehret
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550, Stuttgart, Germany
| | - Vasileios Filippou
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550, Stuttgart, Germany
| | - Svenja Blickle
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550, Stuttgart, Germany
| | - Martina Bubrin
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550, Stuttgart, Germany
| | - Stanislav Záliš
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 18223, Prague, Czech Republic
| | - Wolfgang Kaim
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70550, Stuttgart, Germany
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Abstract
Redox-active unsaturated chelate ligands can be realised with different ring sizes of the resulting metallacycles. An overview is presented, starting from an exposition of non-innocent behaviour and chelate effects. A systematic approach is used to describe the most familiar situation, the metal complexes of 1,4-hetero-1,3-dienes in established forms (e.g. o-quinone, α-dithiolene, and α-diimine ligands) and with less common combinations of O, S, and N heteroatoms. The different steric and electronic conditions in six-membered chelate ring systems derived from the β-diketonate structure will be discussed with examples of substituted and π extended ligands, including 9-oxidophenalenyl, formazanate, and anions derived from indigo or 9,10-anthraquinone. Four-membered chelate rings existing in at least two ligand-based oxidation states are available through steric and electronic stabilisation in amidinate or triazenide complexes. Three-membered and seven-membered chelate ring situations are discussed briefly as further alternatives.
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Affiliation(s)
- Wolfgang Kaim
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
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Uhl W, Honacker C, Lawrence N, Hepp A, Schürmann L, Layh M. Hydroalumination of Oligoalkynylgermanes and -digermanes - Reactions with Heterocumulenes by Al-C or Ge-C Bond Activation and Formation of a Hexazenedialuminum Complex. Z Anorg Allg Chem 2018. [DOI: 10.1002/zaac.201800159] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Werner Uhl
- Institut für Anorganische und Analytische Chemie; Universität Münster; Corrensstraße 30 48149 Münster Germany
| | - Christian Honacker
- Institut für Anorganische und Analytische Chemie; Universität Münster; Corrensstraße 30 48149 Münster Germany
| | - Neil Lawrence
- Institut für Anorganische und Analytische Chemie; Universität Münster; Corrensstraße 30 48149 Münster Germany
| | - Alexander Hepp
- Institut für Anorganische und Analytische Chemie; Universität Münster; Corrensstraße 30 48149 Münster Germany
| | - Lina Schürmann
- Institut für Anorganische und Analytische Chemie; Universität Münster; Corrensstraße 30 48149 Münster Germany
| | - Marcus Layh
- Institut für Anorganische und Analytische Chemie; Universität Münster; Corrensstraße 30 48149 Münster Germany
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Hazari AS, Paretzki A, Fiedler J, Zalis S, Kaim W, Lahiri GK. Different manifestations of enhanced π-acceptor ligation at every redox level of [Os(9-OP)L 2] n, n = 2+, +, 0, - (9-OP - = 9-oxidophenalenone and L = bpy or pap). Dalton Trans 2018; 45:18241-18251. [PMID: 27801461 DOI: 10.1039/c6dt03764j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The title complexes were isolated as structurally characterised compounds [OsII(9-OP)L2]ClO4, L = 2,2'-bipyridine (bpy) or 2-phenylazopyridine (pap), and were compared with ruthenium analogues. A reversible one-electron oxidation and up to three reduction processes were observed by voltammetry (CV, DPV) and spectroelectrochemistry (UV-vis-NIR, partially EPR). Supporting calculations (DFT, TD-DFT) were used to assess the oxidation state combinations of the different redox active ligands and of the metal, revealing the effects of Os versus Ru exchange and of bpy versus pap acceptor ligation. Several unexpected consequences of these variations were observed for members of the new osmium-containing redox series. Remarkably, the EPR results exhibit a clear dichotomy between the complex ion [OsIII(9-OP-)(bpy)2]2+ and the radical species [OsII(9-OP˙)(pap)2]2+, which has not been similarly observed for the analogous [RuIII(9-OP-)L2]2+ systems. This difference, unprecedented for 5dn systems, is attributed to the superior stabilisation of the OsII state by the strongly π-accepting pap ligands. The reduced forms [OsII(9-OP-)(pap˙-)(pap)] and [OsII(9-OP-)(pap˙-)2]- exhibit strong inter-ligand interactions, leading to spin isomers and electron hopping.
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Affiliation(s)
- Arijit Singha Hazari
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | - Alexa Paretzki
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
| | - Jan Fiedler
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejskova 3, CZ-18223 Prague, Czech Republic
| | - Stanislav Zalis
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejskova 3, CZ-18223 Prague, Czech Republic
| | - Wolfgang Kaim
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
| | - Goutam Kumar Lahiri
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
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Kaim W. Electron Transfer Reactivity of Organometallic Compounds Involving Radical-Forming Noninnocent Ligands. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES INDIA SECTION A-PHYSICAL SCIENCES 2016. [DOI: 10.1007/s40010-016-0304-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Li F, Wang ZM, Wu JJ, Wang J, Xie SS, Lan JS, Xu W, Kong LY, Wang XB. Synthesis and pharmacological evaluation of donepezil-based agents as new cholinesterase/monoamine oxidase inhibitors for the potential application against Alzheimer's disease. J Enzyme Inhib Med Chem 2016; 31:41-53. [PMID: 27384289 DOI: 10.1080/14756366.2016.1201814] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
In a continuing effort to develop multitargeted compounds as potential treatment agents against Alzheimer's disease (AD), a series of donepezil-like compounds were designed, synthesized and evaluated. In vitro studies showed that most of the designed compounds displayed potent inhibitory activities toward AChE, BuChE, MAO-B and MAO-A. Among them, w18 was a promising agent with balanced activities, which exhibited a moderate cholinesterase inhibition (IC50, 0.220 μM for eeAChE; 1.23 μM for eqBuChE; 0.454 μM for hAChE) and an acceptable inhibitory activity against monoamine oxidases (IC50, 3.14 μM for MAO-B; 13.4 μM for MAO-A). Moreover, w18 could also be a metal-chelator, and able to cross the blood-brain barrier with low cell toxicity on PC12 cells. Taken together, these results suggested that w18 might be a promising multitargeted compound for AD treatment.
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Affiliation(s)
- Fan Li
- a State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University , People's Republic of China
| | - Zhi-Min Wang
- a State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University , People's Republic of China
| | - Jia-Jia Wu
- a State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University , People's Republic of China
| | - Jin Wang
- a State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University , People's Republic of China
| | - Sai-Sai Xie
- a State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University , People's Republic of China
| | - Jin-Shuai Lan
- a State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University , People's Republic of China
| | - Wei Xu
- a State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University , People's Republic of China
| | - Ling-Yi Kong
- a State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University , People's Republic of China
| | - Xiao-Bing Wang
- a State Key Laboratory of Natural Medicines, Department of Natural Medicinal Chemistry, China Pharmaceutical University , People's Republic of China
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Tang JH, Yao CJ, Cui BB, Zhong YW. Ruthenium-Amine Conjugated Organometallic Materials for Multistate Near-IR Electrochromism and Information Storage. CHEM REC 2016; 16:754-67. [DOI: 10.1002/tcr.201500252] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Jian-Hong Tang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences; 2 Bei Yi Jie Zhong Guan Cun Beijing 100190 P. R. China
| | - Chang-Jiang Yao
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences; 2 Bei Yi Jie Zhong Guan Cun Beijing 100190 P. R. China
| | - Bin-Bin Cui
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences; 2 Bei Yi Jie Zhong Guan Cun Beijing 100190 P. R. China
| | - Yu-Wu Zhong
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences; 2 Bei Yi Jie Zhong Guan Cun Beijing 100190 P. R. China
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Xu W, Wang XB, Wang ZM, Wu JJ, Li F, Wang J, Kong LY. Synthesis and evaluation of donepezil–ferulic acid hybrids as multi-target-directed ligands against Alzheimer's disease. MEDCHEMCOMM 2016. [DOI: 10.1039/c6md00053c] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A novel family of donepezil–ferulic acid hybrids were designed, synthesized and biologically evaluated as multi-target-directed ligands against Alzheimer's disease by fusing a fragment of donepezil and ferulic acid.
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Affiliation(s)
- Wei Xu
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Xiao-Bing Wang
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Zhi-Min Wang
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Jia-Jia Wu
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Fan Li
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Jin Wang
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
| | - Ling-Yi Kong
- State Key Laboratory of Natural Medicines
- Department of Natural Medicinal Chemistry
- China Pharmaceutical University
- Nanjing 210009
- People's Republic of China
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Nie HJ, Yang WW, Shao JY, Zhong YW. Ruthenium-tris(bipyridine) complexes with multiple redox-active amine substituents: tuning of spin density distribution and deep-red to NIR electrochromism and electrofluorochromism. Dalton Trans 2016; 45:10136-40. [DOI: 10.1039/c6dt02014c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Deep-red to NIR electrochromism and electrofluorochromism are demonstrated with ruthenium-tris(bipyridine) complexes with multiple amine substituents.
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Affiliation(s)
- Hai-Jing Nie
- Beijing National Laboratory for Molecular Sciences
- CAS Key Laboratory of Photochemistry
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Wen-Wen Yang
- Beijing National Laboratory for Molecular Sciences
- CAS Key Laboratory of Photochemistry
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Jiang-Yang Shao
- Beijing National Laboratory for Molecular Sciences
- CAS Key Laboratory of Photochemistry
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
| | - Yu-Wu Zhong
- Beijing National Laboratory for Molecular Sciences
- CAS Key Laboratory of Photochemistry
- Institute of Chemistry
- Chinese Academy of Sciences
- Beijing 100190
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