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Qian J, Comito RJ. Site-Isolated Main-Group Tris(2-pyridyl)borate Complexes by Pyridine Substitution and Their Ring-Opening Polymerization Catalysis. Inorg Chem 2022; 61:10852-10862. [PMID: 35776081 DOI: 10.1021/acs.inorgchem.2c01289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tris(2-pyridyl)borates are an emerging class of scorpionate ligands, distinguished as exceptionally robust and electron-donating. However, the rapid formation of inert homoleptic complexes with divalent metals has so far limited their catalytic utility. We report site-isolating tris(2-pyridyl)borate ligands, bearing isopropyl, tert-butyl, and mesityl substituents at the pyridine 6-position to suppress the formation of inert homoleptic complexes. These ligands form the first 1:1 complexes between tris(2-pyridyl)borates and Mg2+, Zn2+, or Ca2+, with isopropyl-substituted TpyiPrH showing the most generality. Single-crystal X-ray diffraction analysis of the resulting complexes and comparison to density functional theory (DFT) models showed geometric distortions driven by steric repulsion between the pyridine 6-substituents and the hexamethyldisilazide (HMDS-, -N(SiMe3)2) anion. We show that this steric profile is a feature of the six-membered pyridine ring and contrasts with more established tris(pyrazolyl)borate and tris(imidazoline)borate scorpionate complexes. TpyiPrMg(HMDS) (1) and its zinc analogue are moderately active for the controlled polymerization of l-lactide, ε-caprolactone, and trimethylene carbonate. Furthermore, 1 gives controlled polymerization under more demanding melt-phase polymerization conditions at 100 °C, and block copolymerization of ε-caprolactone and trimethylene carbonate. These results will enable useful catalysis and coordination chemistry studies with tris(2-pyridyl)borates, and characterizes their structural complementarity to more familiar scorpionate ligands.
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Affiliation(s)
- Jin Qian
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
| | - Robert J Comito
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
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2
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Müller L, Nadurata VL, Cula B, Hoof S, Herwig C, Limberg C. Versatile Coordination Behavior of the Asymmetric Bis(3‐mesityl‐pyrazol‐1‐yl)(5‐mesitylpyrazol‐1‐yl) Hydroborate Ligand towards Late 3 d M
2+
Ions. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Lars Müller
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Vincent L. Nadurata
- School of Chemistry University of Melbourne Parkville Victoria 3010 Australia
| | - Beatrice Cula
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Santina Hoof
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Christian Herwig
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Christian Limberg
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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3
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Siepi M, Oliva R, Battista F, Petraccone L, Del Vecchio P, Izzo V, Dal Piaz F, Isticato R, Notomista E, Donadio G. Molecular Dissection of dH3w, A Fluorescent Peptidyl Sensor for Zinc and Mercury. SENSORS (BASEL, SWITZERLAND) 2020; 20:E598. [PMID: 31973164 PMCID: PMC7038057 DOI: 10.3390/s20030598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/15/2020] [Accepted: 01/17/2020] [Indexed: 12/24/2022]
Abstract
Previously, we reported that fluorescent peptide dansyl-HPHGHW-NH2 (dH3w), designed on the repeats of the human histidine-rich glycoprotein, shows a turn-on response to Zn(II) and a complex response to Hg(II) characterized by a turn-off phase at low Hg(II) concentrations and a turn-on phase at high concentrations. As Hg(II) easily displaces Zn(II), dH3w is a useful probe for the environmental monitoring of Hg(II). In order to investigate the molecular basis of the metal selectivity and fluorescence response, we characterized three variants, dH3w(H1A), dH3w(H3A), and dH3w(H5A), in which each of the three histidine residues was changed to alanine, and two variants with a single fluorescent moiety, namely dH3w(W6A), in which the tryptophan residue at the C-terminus was changed to alanine, and AcH3w, in which the N-terminal dansyl moiety was substituted by an acetyl group. These variants allowed us to demonstrate that all the histidine residues are essential for a strong interaction with Zn(II), whereas two histidine residues (in particular His5) and the dansyl group are necessary to bind Hg(II). The data reported herein shed light on the molecular behavior of dH3w, thus paving the way to the rational designing of further and more efficient fluorescent peptidyl probes for Hg(II).
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Affiliation(s)
- Marialuisa Siepi
- Department of Biology, University of Naples Federico II, Via Cintia, 80126 Naples, Italy; (M.S.); (R.I.)
| | - Rosario Oliva
- Physical Chemistry I, TU Dortmund University, Otto-Hahn-Str. 4a, 44227 Dortmund, Germany;
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, 80126 Naples, Italy; (F.B.); (L.P.); (P.D.V.)
| | - Filomena Battista
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, 80126 Naples, Italy; (F.B.); (L.P.); (P.D.V.)
| | - Luigi Petraccone
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, 80126 Naples, Italy; (F.B.); (L.P.); (P.D.V.)
| | - Pompea Del Vecchio
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia, 80126 Naples, Italy; (F.B.); (L.P.); (P.D.V.)
| | - Viviana Izzo
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Via Salvador Allende, 84081 Baronissi, Italy; (V.I.); (F.D.P.)
| | - Fabrizio Dal Piaz
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Via Salvador Allende, 84081 Baronissi, Italy; (V.I.); (F.D.P.)
| | - Rachele Isticato
- Department of Biology, University of Naples Federico II, Via Cintia, 80126 Naples, Italy; (M.S.); (R.I.)
| | - Eugenio Notomista
- Department of Biology, University of Naples Federico II, Via Cintia, 80126 Naples, Italy; (M.S.); (R.I.)
| | - Giuliana Donadio
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Via Salvador Allende, 84081 Baronissi, Italy; (V.I.); (F.D.P.)
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4
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Hoof S, Limberg C. The Behavior of Trispyrazolylborato-Metal(II)-Flavonolate Complexes as Functional Models for Bacterial Quercetinase-Assessment of the Metal Impact. Inorg Chem 2019; 58:12843-12853. [PMID: 31502453 DOI: 10.1021/acs.inorgchem.9b01795] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A series of five compounds TpMesMFla (TpMes = hydrotris(3-mesityl)pyrazolylborate; M = Mn, Fe, Co, Ni, Zn; Fla = 3-hydroxyflavonolate) has been synthesized as models for the 2,4-quercetin dioxygenase, QueD. The structures have been determined and the complexes proved to be isomorphous. Considering the structures more closely revealed that they differ in the degree of delocalization in the chelate ring formed through the binding of the two O donors of the flavonolate to the metal center, which is also supported by the results of UV-vis and IR spectroscopic investigations. The resulting trend (Zn/Fe > Co > Mn > Ni) is, however, not in line with the one that was found investigating the redox properties of the complexes by cyclic voltammetry (Zn > Fe > Ni > Co > Mn). Notably, from CV clear-cut information could be derived, as the complexes exhibited exceptionally well-behaved quasi-reversible redox transitions, indicating that the Tp ligand stabilizes the flavonolate radical formed in the oxidation process rather well. The fact that the rates, with which the complexes react with O2 in DMF solution, correlate with the position of the flavonolate redox couples, suggest that these reactions proceed via the initial electron transfer from the flavonolate to O2. After the O2 reaction, salicylic acid was identified as one of the products, the formation of which can be explained by the hydrolysis of the depside that should form upon a dioxygenation similar to the QueD enzyme-catalyzed reaction. 18O labeling experiments confirmed the presence of O2 derived O atoms. Mechanistic inferences based on the above results are discussed.
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Affiliation(s)
- Santina Hoof
- Institut für Chemie , Humboldt-Universität zu Berlin , Brook-Taylor-Str. 2 , 12489 Berlin , Germany
| | - Christian Limberg
- Institut für Chemie , Humboldt-Universität zu Berlin , Brook-Taylor-Str. 2 , 12489 Berlin , Germany
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5
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Abubekerov M, Diaconescu PL. Synthesis and characterization of ferrocene-chelating heteroscorpionate complexes of nickel(II) and zinc(II). Inorg Chem 2015; 54:1778-84. [PMID: 25607817 DOI: 10.1021/ic502691b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The first example of a ferrocene-chelating heteroscorpionate, [Li(THF)2][fc(PPh2)(BH[(3,5-Me)2pz]2)] ((fc(P,B))Li(THF)2, fc = 1,1'-ferrocenediyl) is described. Starting from a previously reported compound, fcBr(PPh2), a series of ferrocene derivatives, fc(PPh2)(B[OMe]2), [Li(OEt2)][fc(PPh2)(BH3)], [Li(THF)2][fc(PPh2)(BH[(3,5-Me)2pz]2)] (pz = pyrazole), was isolated and characterized. Compound (fc(P,B))Li(THF)2 allowed the synthesis of the corresponding nickel and zinc complexes, (fc(P,B))NiCl, (fc(P,B))NiMe, (fc(P,B))ZnCl, and (fc(P,B))ZnMe. All compounds were characterized by NMR spectroscopy, while the zinc and nickel complexes were also characterized by X-ray crystallography. The redox behavior of (fc(P,B))NiCl, (fc(P,B))NiMe, (fc(P,B))ZnCl, and (fc(P,B))ZnMe was studied by cyclic voltammetry and supported by density functional theory calculations.
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Affiliation(s)
- Mark Abubekerov
- Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States
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Cardenas AJP, Abelman R, Warren TH. Conversion of nitrite to nitric oxide at zinc via S-nitrosothiols. Chem Commun (Camb) 2014; 50:168-70. [PMID: 24217415 DOI: 10.1039/c3cc46102e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Nitrite is an important reservoir of nitric oxide activity in the plasma and cells. Using a biomimetic model, we demonstrate the conversion of zinc-bound nitrite in the tris(pyrazolyl)borate complex (iPr2)TpZn(NO2) to the corresponding S-nitrosothiol RSNO and zinc thiolate (iPr2)TpZn-SR via reaction with thiols H-SR. Decomposition of the S-nitrosothiol formed releases nitric oxide gas.
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Affiliation(s)
- Allan Jay P Cardenas
- Department of Chemistry, Georgetown University, Box 571227-1227, Washington, D.C. 20057, USA.
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Pettinari C, Marchetti F, Orbisaglia S, Palmucci J, Pettinari R, Di Nicola C, Skelton BW, White AH. Synthesis, Characterization, and Crystal Structures of Scorpionate Complexes with the Hydrotris[3-(2′-thienyl)pyrazol-1-yl]borate Ligand. Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201301153] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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8
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Chu W, Wang Y, Liu S, Yang X, Wang S, Li S, Zhou G, Qin X, Zhou C, Zhang J. Synthesis, cytotoxicity and DNA-binding properties of Pd(II), Cu(II) and Zn(II) complexes with 4′-(4-(2-(piperidin-1-yl)ethoxy)phenyl)-2,2′:6′,2″-terpyridine. Bioorg Med Chem Lett 2013; 23:5187-91. [DOI: 10.1016/j.bmcl.2013.07.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 06/20/2013] [Accepted: 07/04/2013] [Indexed: 12/11/2022]
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9
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Wang S, Chu W, Wang Y, Liu S, Zhang J, Li S, Wei H, Zhou G, Qin X. Synthesis, characterization and cytotoxicity of Pt(II), Pd(II), Cu(II) and Zn(II) complexes with 4’-substituted terpyridine. Appl Organomet Chem 2013. [DOI: 10.1002/aoc.2988] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Shuxiang Wang
- Key Laboratory of Chemical Biology of Hebei Province; College of Chemistry and Environmental ScienceHebei University; Baoding 071002 People's Republic of China
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education; Hebei University; Baoding 071002 People's Republic of China
| | - Wenhao Chu
- Key Laboratory of Chemical Biology of Hebei Province; College of Chemistry and Environmental ScienceHebei University; Baoding 071002 People's Republic of China
| | - Yuechai Wang
- Key Laboratory of Chemical Biology of Hebei Province; College of Chemistry and Environmental ScienceHebei University; Baoding 071002 People's Republic of China
| | - Siyuan Liu
- Key Laboratory of Chemical Biology of Hebei Province; College of Chemistry and Environmental ScienceHebei University; Baoding 071002 People's Republic of China
| | - Jinchao Zhang
- Key Laboratory of Chemical Biology of Hebei Province; College of Chemistry and Environmental ScienceHebei University; Baoding 071002 People's Republic of China
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education; Hebei University; Baoding 071002 People's Republic of China
| | - Shenghui Li
- Key Laboratory of Chemical Biology of Hebei Province; College of Chemistry and Environmental ScienceHebei University; Baoding 071002 People's Republic of China
| | - Haiying Wei
- Key Laboratory of Chemical Biology of Hebei Province; College of Chemistry and Environmental ScienceHebei University; Baoding 071002 People's Republic of China
| | - Guoqiang Zhou
- Key Laboratory of Chemical Biology of Hebei Province; College of Chemistry and Environmental ScienceHebei University; Baoding 071002 People's Republic of China
| | - Xinying Qin
- Key Laboratory of Chemical Biology of Hebei Province; College of Chemistry and Environmental ScienceHebei University; Baoding 071002 People's Republic of China
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10
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Kumar M, Papish ET, Zeller M, Hunter AD. Zinc complexes of TtzR,Me with O and S donors reveal differences between Tp and Ttz ligands: acid stability and binding to H or an additional metal (TtzR,Me = tris(3-R-5-methyl-1,2,4-triazolyl)borate; R = Ph, tBu). Dalton Trans 2011; 40:7517-33. [DOI: 10.1039/c1dt10429b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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