1
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Beagan DM, Rivera C, Szymczak NK. Appended Lewis Acids Enable Dioxygen Reactivity and Catalytic Oxidations with Ni(II). J Am Chem Soc 2024; 146:12375-12385. [PMID: 38661576 PMCID: PMC11148854 DOI: 10.1021/jacs.3c12399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
We disclose a suite of Ni(II) complexes featuring secondary sphere Lewis acids of varied Lewis acidity and tether lengths. Several of these complexes feature atypical behavior of Ni(II): reactivity with O2 that occurs only in the presence of a tethered Lewis acid. In situ UV-vis spectroscopy revealed that, although adducts are stable at -40 °C, complexes containing 9-borabicyclo[3.3.1]nonane (9-BBN) Lewis acids underwent irreversible oxidative deborylation when warmed to room temperature. We computationally and experimentally identified that oxidative instability of appended 9-BBN moieties can be mitigated using weaker Lewis acids such as pinacolborane (BPin). These insights enabled the realization of catalytic reactions: hydrogen atom abstraction from phenols and room temperature oxygen atom transfer to PPh3.
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Affiliation(s)
- Daniel M Beagan
- University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Carolina Rivera
- University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Nathaniel K Szymczak
- University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
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2
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Das A, Chakraborty S, Mandal SK. Abnormal N-heterocyclic Carbene Based Ni(II) π-allyl Complex towards Molecular Oxygen Activation. Chem Asian J 2021; 16:2257-2260. [PMID: 34137185 DOI: 10.1002/asia.202100568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/15/2021] [Indexed: 11/08/2022]
Abstract
Abnormal N-heterocyclic carbene (aNHC) based Ni(II) π-allyl complexes (3 and 4) were synthesized starting from a Ni(0) precursor. These complexes were characterized by NMR spectroscopy, single-crystal X-ray crystallography (4) and elemental analysis data. The underlying mechanism for the formation of Ni(II) η3 -allyl complexes from a Ni(0) precursor on treatment with a free abnormal N-heterocyclic carbene in absence of any external additive or oxidant was unraveled. Later, complex 3 was exposed to O2 gas under ambient pressure resulting in molecular oxygen activation to form a μ-hydroxo bridged Ni(II) dimer.
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Affiliation(s)
- Arpan Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
| | - Soumi Chakraborty
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
| | - Swadhin K Mandal
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
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3
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Salerno EV, Kadel LR, Eichhorn DM. Ethanol(nitrato)[tris-(4-cyano-3-phenyl-1 H-pyrazol-1-yl)hydroborato]nickel(II). IUCRDATA 2021; 6:x210690. [PMID: 36340660 PMCID: PMC9462359 DOI: 10.1107/s2414314621006908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 07/05/2021] [Indexed: 11/24/2022] Open
Abstract
The synthesis and structure is reported of TpPh,4CNNi(NO3)(EtOH) or [Ni(C30H19BN9)(NO3)(C2H6O)], the first half-sandwich complex of a cyano-scorpionate ligand. The pseudo-octa-hedral coordination sphere of the NiII ion is comprised of a tridentate tris-(4-cyano-3-phenyl-pyrazol-yl)borate ligand, a bidentate nitrate ligand and a neutral ethanol ligand. The phenyl substituents on the TpPh,4CN ligand are relatively parallel to the planes of the ethanol and nitrate ligands. An inter-molecular hydrogen-bonding inter-action is evident between the ethanol OH group and the pyrazole CN substituent. The ethanol ligand was modeled with a 0.572 (13)/0.428 (13) disorder of the methyl C atom.
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Affiliation(s)
- Elvin V. Salerno
- Department of Chemistry and Biochemistry, Wichita State University, 1845 Fairmount St., Wichita, KS 67260-0051, USA
| | - Lava R. Kadel
- Department of Chemistry and Biochemistry, Wichita State University, 1845 Fairmount St., Wichita, KS 67260-0051, USA
| | - David M. Eichhorn
- Department of Chemistry and Biochemistry, Wichita State University, 1845 Fairmount St., Wichita, KS 67260-0051, USA
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4
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Cordeiro LL, Dmitrenko O, Yap GPA, Riordan CG. Synthesis and Reactivity Studies of a Series of Nickel(II) Arylchalcogenolates. Inorg Chem 2021; 60:6327-6338. [PMID: 33851821 DOI: 10.1021/acs.inorgchem.1c00066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two series of high-spin nickel complexes, [TpPh,Me]Ni(EAr) (E = O, Se, Te; Ar = C6H5) and [TpPh,Me]Ni(SeC6H4-4-X) (X = H, Cl, Me, OMe), were prepared by metathetical reaction of the nickel(II) halide precursor with sodium salts of the corresponding chalcogen, NaEAr. X-ray crystallographic characterization and spectroscopic studies have established the geometric and electronic structures of these complexes. The observed spectroscopic and structural characteristics reveal distinct trends in accordance with the variation of the identity of the arylchalcogenolate and para substituent. Reaction of the [TpPh,Me]Ni(EAr) complexes with methyl iodide proceeded readily, producing the corresponding methylarylchalcogen and [TpPh,Me]NiI. A kinetic and computational analysis of the reaction of [TpPh,Me]Ni(SeC6H5) with MeI supports that the electrophilic alkylation reactions occur via an associative mechanism via a classical SN2 transition state.
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Affiliation(s)
- Lauren L Cordeiro
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Olga Dmitrenko
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Glenn P A Yap
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Charles G Riordan
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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5
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Suzuki T, Sato A, Oshita H, Yajima T, Tani F, Abe H, Mieda-Higa K, Yanagisawa S, Ogura T, Shimazaki Y. Formation of Ni(II)-phenoxyl radical complexes by O 2: a mechanistic insight into the reaction of Ni(II)-phenol complexes with O 2. Dalton Trans 2021; 50:5161-5170. [PMID: 33881085 DOI: 10.1039/d1dt00105a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A reaction of Ni(ClO4)2·6H2O with a tripodal ligand having two di(tert-butyl)phenol moieties, H2tbuL, and 1 equivalent of triethylamine in CH2Cl2/CH3OH (1 : 1, v/v) under N2 gave a NiII-(phenol)(phenolate) complex, [Ni(HtbuL)(CH3OH)2]ClO4. The formation of the NiII-phenoxyl radical complex by O2 was observed in the reaction of this complex in the solid state. On the other hand, the NiII-phenoxyl radical complex [Ni(Me2NL)(CH3OH)2]ClO4 was obtained by the reaction of H2Me2NL having a p-(dimethylamino)phenol moiety with Ni(ClO4)2·6H2O in a similar procedure under O2, through the oxidation of the NiII-(phenol)(phenolate) complex. However, a direct redox reaction of the NiII ion could not be detected in the phenoxyl radical formation. The results of the reaction kinetics, XAS and X-ray structure analyses suggested that the O2 oxidation from the NiII-(phenol)(phenolate) complex to the NiII-phenoxyl radical complex occurs via the proton transfer-electron transfer (PT-ET) type mechanism of the phenol moiety weakly coordinated to the nickel ion.
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Affiliation(s)
- Takashi Suzuki
- Graduate School of Science and Engineering, Ibaraki University, Mito 310-8512, Japan.
| | - Akari Sato
- Graduate School of Science and Engineering, Ibaraki University, Mito 310-8512, Japan.
| | - Hiromi Oshita
- Faculty of Chemistry of Functional Molecules, Konan University, Higashinada-ku, Kobe 658-8501, Japan
| | - Tatsuo Yajima
- Faculty of Chemistry, Materials and Bioengineering, Kansai University, Suita, Osaka 564-8680, Japan
| | - Fumito Tani
- Institute for Materials Chemistry and Engineering, Kyushu University, Nishi-Ku, Fukuoka 819-0395, Japan
| | - Hitoshi Abe
- Graduate School of Science and Engineering, Ibaraki University, Mito 310-8512, Japan. and Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK) 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan and Department of Materials Structure Science, School of High Energy Accelerator Science, SOKENDAI (the Graduate University for Advanced Studies), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Kaoru Mieda-Higa
- Graduate School of Life Science, University of Hyogo, Kamigori, Hyogo 678-1297, Japan
| | - Sachiko Yanagisawa
- Graduate School of Life Science, University of Hyogo, Kamigori, Hyogo 678-1297, Japan
| | - Takashi Ogura
- Graduate School of Life Science, University of Hyogo, Kamigori, Hyogo 678-1297, Japan
| | - Yuichi Shimazaki
- Graduate School of Science and Engineering, Ibaraki University, Mito 310-8512, Japan.
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6
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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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7
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In‐situ
Formation of a Dinuclear Al(III) Complex in Friedel‐Crafts Sulfoxidation of 2‐Naphthol with Thionyl Chloride. ChemistrySelect 2019. [DOI: 10.1002/slct.201900321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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8
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Kim J, Park K, Lee Y. Synthesis and characterization of a four-coordinate nickel carbamato species (MeSiP i Pr 2 )Ni(OC(O)NHMes) generated from the reaction of (MeSiP i Pr 2 )Ni(NHMes) with CO 2. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2016.08.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Green WL, Sirianni ER, Yap GPA, Riordan CG. Steric and electronic factor comparisons in hydrotris(3-phenylpyrazolyl)borate nickel(II) aryloxides. Acta Crystallogr C Struct Chem 2016; 72:791-796. [PMID: 27811413 DOI: 10.1107/s2053229616001789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 01/29/2016] [Indexed: 11/10/2022] Open
Abstract
Hydrotris(pyrazolyl)borate (Tp) ligands, also known as scorpionates, are potent tridentate donors that effectively bind metal ions in a face-capping array. Hydrotris(3-phenylpyrazolyl)borate enforces a tetrahedral environment on NiII to model metalloenzymes. The syntheses and structural characterizations of a number of [hydrotris(3-phenylpyrazolyl)borato]nickel(II) aryloxides were performed to provide insight into the environment of the model active site; these compounds are chlorido[hydrotris(3-phenylpyrazolyl-κN2)borato](3-phenyl-1H-pyrazole-κN2)nickel(II) chloroform monosolvate, [Ni(C27H22BN6)Cl(C9H8N2)]·CHCl3, (2), [hydrotris(3-phenylpyrazolyl-κN2)borato](phenolato-κO)nickel(II), [Ni(C27H22BN6)(C6H5O)], (3), (2,6-dimethylphenolato-κO)[hydrotris(3-phenylpyrazolyl-κN2)borato]nickel(II) [Ni(C27H22BN6)(C8H9O)], (4), (4-tert-butylphenolato-κO)[hydrotris(3-phenylpyrazolyl-κN2)borato]nickel(II), [Ni(C27H22BN6)(C10H13O)], (5), and [hydrotris(3-phenylpyrazolyl-κN2)borato](phenolato-κO)(tetrahydrofuran-κO)nickel(II) tetrahydrofuran monosolvate, [Ni(C27H22BN6)(C6H5O)(C4H8O)]·C4H8O, (6). Alkyl groups, e.g. tert-butyl in (5) and methyl in (4), electronically activate the aryloxide group to intramolecular π-π stacking but can be frustrated by steric encumbrance at the interacting ring faces. The flexibility at the nickel coordination site, afforded by the uncrowded B atom of the TpPh ligand, allows tetrahydrofuran coordination in the phenolate compound.
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Affiliation(s)
- William L Green
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Eric R Sirianni
- Sabine River Laboratory B568, INVISTA, Orange, TX 77631, USA
| | - Glenn P A Yap
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Charles G Riordan
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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10
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Structural characterization and electrochemical properties of nickel (II) complexes bearing sterically bulky hydrotris(3-phenyl)- and hydrotris(3-tert-butylpyrazol-1-yl)borato ligands. Polyhedron 2016. [DOI: 10.1016/j.poly.2015.11.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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11
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Kadel LR, Bullinger JR, Baum RR, Moore CE, Tierney DL, Eichhorn DM. Cyanoscorpionate Ligands: Agostic Interactions in a Series of Metal Complexes Containing the Tris(4‐cyano‐3‐phenylpyrazolyl)borate and Bis(4‐cyano‐3‐phenylpyrazolyl)borate Ligands. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201501268] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Lava R. Kadel
- Department of ChemistryWichita State University67260WichitaKSUSA
| | | | - Robert R. Baum
- Department of Chemistry and BiochemistryMiami University45056SAOxfordOHUSA
| | - Curtis E. Moore
- Department of Chemistry and BiochemistryUniversity of CaliforniaSan DiegoCAUSA
| | - David L. Tierney
- Department of Chemistry and BiochemistryMiami University45056SAOxfordOHUSA
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12
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Ghorui T, Roy S, Pramanik S, Pramanik K. RhCl(PPh3)3-mediated C–H oxyfunctionalization of pyrrolido-functionalized bisazoaromatic pincers: a combined experimental and theoretical scrutiny of redox-active and spectroscopic properties. Dalton Trans 2016; 45:5720-9. [DOI: 10.1039/c5dt05044h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Non-trivial coordination mode of symmetrical NNN ligands with Rh(iii) leads to redox-active NNO-scaffolds via C(sp2)–H oxyfunctionalization at rt, opening an opportunity to juxtapose different redox-active domains.
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Affiliation(s)
- Tapas Ghorui
- Department of Chemistry
- Inorganic Chemistry Section
- Jadavpur University
- Kolkata – 700032
- India
| | - Sima Roy
- Department of Chemistry
- Inorganic Chemistry Section
- Jadavpur University
- Kolkata – 700032
- India
| | - Shuvam Pramanik
- Department of Chemistry
- Inorganic Chemistry Section
- Jadavpur University
- Kolkata – 700032
- India
| | - Kausikisankar Pramanik
- Department of Chemistry
- Inorganic Chemistry Section
- Jadavpur University
- Kolkata – 700032
- India
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13
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Ou YC, Chen HC, Liang YH, Tang JJ, Feng SB, Peng L, Wu JZ. Crystal structures, in situ synthesis in aqua conditions and luminescent properties of benzimidazole ligands and cadmium coordination complexes. Inorganica Chim Acta 2015. [DOI: 10.1016/j.ica.2015.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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14
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Deb T, Jensen MP. Electrophilic alkylation of pseudotetrahedral nickel(II) arylthiolate complexes. Inorg Chem 2015; 54:87-96. [PMID: 25494529 DOI: 10.1021/ic5018328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A kinetic study is reported for reactions of pseudotetrahedral nickel(II) arylthiolate complexes [(Tp(R,Me))Ni-SAr] (Tp(R,Me) = hydrotris{3-R-5-methyl-1-pyrazolyl}borate, R = Me, Ph, and Ar = C6H5, C6H4-4-Cl, C6H4-4-Me, C6H4-4-OMe, 2,4,6-Me3C6H2, 2,4,6-(i)Pr3C6H2) with organic electrophiles R'X (i.e., MeI, EtI, BzBr) in low-polarity organic solvents (toluene, THF, chloroform, dichloromethane, or 1,2-dichloroethane), yielding a pseudotetrahedral halide complex [(Tp(R,Me))Ni-X] (X = Cl, Br, I) and the corresponding organosulfide R'SAr. Competitive reactions with halogenated solvents and adventitious air were also examined. Akin to reactions of analogous and biomimetic zinc complexes, a pertinent mechanistic question is the nature of the reactive nucleophile, either an intact thiolate complex or a free arylthiolate resulting from a dissociative pre-equilibrium. The observed kinetics conformed to a second-order rate law, first order with respect to the complex and electrophile, and no intermediate complexes were observed. In the absence of a mechanistically diagnostic rate law, a variety of mechanistic probes were examined, including kinetic effects of varying the metal, solvent, electrophile, and temperature, as well as the 3-pyrazolyl and arylthiolate substituents. Compared to zinc analogues, the effect of Ni-SAr covalency is also of interest herein. The results are broadly interpreted with respect to the disparate mechanistic pathways.
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Affiliation(s)
- Tapash Deb
- Department of Chemistry and Biochemistry, Ohio University , Athens, Ohio 45701, United States
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15
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Deb T, Anderson CM, Ma H, Petersen JL, Young VG, Jensen MP. Scorpionato Halide Complexes [(Tp
Ph,Me
)Ni–X] [X = Cl, Br, I; Tp
Ph,Me
= Hydrotris(3‐phenyl‐5‐methyl‐1‐pyrazolyl)borate]: Structures, Spectroscopy, and Pyrazole Adducts. Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201402897] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Tapash Deb
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, U.S.A., http://www.ohio.edu/chemistry/faculty/jensen.php
| | - Caitlin M. Anderson
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, U.S.A., http://www.ohio.edu/chemistry/faculty/jensen.php
| | - Huaibo Ma
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, U.S.A., http://www.ohio.edu/chemistry/faculty/jensen.php
| | - Jeffrey L. Petersen
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, U.S.A
| | - Victor G. Young
- X‐ray Crystallographic Laboratory, Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, U.S.A
| | - Michael P. Jensen
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, U.S.A., http://www.ohio.edu/chemistry/faculty/jensen.php
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16
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Deb T, Anderson CM, Chattopadhyay S, Ma H, Young VG, Jensen MP. Steric and electronic effects on arylthiolate coordination in the pseudotetrahedral complexes [(Tp(Ph,Me))Ni-SAr] (Tp(Ph,Me) = hydrotris{3-phenyl-5-methyl-1-pyrazolyl}borate). Dalton Trans 2014; 43:17489-99. [PMID: 25341014 DOI: 10.1039/c4dt02726d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthesis and characterization of several new pseudotetrahedral arylthiolate complexes [(Tp(Ph,Me))Ni-SAr] (Tp(Ph,Me) = hydrotris{3-phenyl-5-methyl-1-pyrazolyl}borate; Ar = Ph, 2,4,6-(i)Pr3C6H2, C6H4-4-Cl, C6H4-4-Me, C6H4-4-OMe) are reported, including X-ray crystal structures of the first two complexes. With prior results, two series of complexes are spanned, [(Tp(Ph,Me))Ni-S-2,4,6-RC6H2] (R'' = H, Me, (i)Pr) plus the xylyl analogue [(Tp(Ph,Me))Ni-S-2,6-Me2C6H3], as well as [(Tp(Ph,Me))Ni-S-C6H4-4-Y] (Y = Cl, H, Me, OMe), intended to elucidate steric and/or electronic effects on arylthiolate coordination. In contrast to [(Tp(Me,Me))Ni-SAr] analogues that adopt a sawhorse conformation, the ortho-disubstituted complexes show enhanced trigonal and Ni-S-Ar bending, reflecting the size of the 3-pyrazole substituents. Moreover, weakened scorpionate ligation is implied by spectroscopic data. Little spectroscopic effect is observed in the series of para-substituted complexes, suggesting the observed effects are primarily steric in origin. The relatively electron-rich and encumbered complex [(Tp(Ph,Me))Ni-S-2,4,6-(i)Pr3C6H2] behaves uniquely when dissolved in CH3CN, forming a square planar solvent adduct with a bidentate scorpionate ligand, [(κ(2)-Tp(Ph,Me))Ni(NCMe)(S-2,4,6-(i)Pr3C6H2)]. This adduct was isolated and characterized by X-ray crystallography. Single-point DFT and TD-DFT calculations on a simplified [(κ(2)-Tp)Ni(NCMe)(SPh)] model were used to clarify the electronic spectrum of the adduct, and to elucidate differences between Ni-SAr bonding and spectroscopy between pseudotetrahedral and square planar geometries.
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Affiliation(s)
- Tapash Deb
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, USA.
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17
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Machonkin TE, Boshart MD, Schofield JA, Rodriguez MM, Grubel K, Rokhsana D, Brennessel WW, Holland PL. Structural and spectroscopic characterization of iron(II), cobalt(II), and nickel(II) ortho-dihalophenolate complexes: insights into metal-halogen secondary bonding. Inorg Chem 2014; 53:9837-48. [PMID: 25167329 DOI: 10.1021/ic501424e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metal complexes incorporating the tris(3,5-diphenylpyrazolyl)borate ligand (Tp(Ph2)) and ortho-dihalophenolates were synthesized and characterized in order to explore metal-halogen secondary bonding in biorelevant model complexes. The complexes Tp(Ph2)ML were synthesized and structurally characterized, where M was Fe(II), Co(II), or Ni(II) and L was either 2,6-dichloro- or 2,6-dibromophenolate. All six complexes exhibited metal-halogen secondary bonds in the solid state, with distances ranging from 2.56 Å for the Tp(Ph2)Ni(2,6-dichlorophenolate) complex to 2.88 Å for the Tp(Ph2)Fe(2,6-dibromophenolate) complex. Variable temperature NMR spectra of the Tp(Ph2)Co(2,6-dichlorophenolate) and Tp(Ph2)Ni(2,6-dichlorophenolate) complexes showed that rotation of the phenolate, which requires loss of the secondary bond, has an activation barrier of ~30 and ~37 kJ/mol, respectively. Density functional theory calculations support the presence of a barrier for disruption of the metal-halogen interaction during rotation of the phenolate. On the other hand, calculations using the spectroscopically calibrated angular overlap method suggest essentially no contribution of the halogen to the ligand-field splitting. Overall, these results provide the first quantitative measure of the strength of a metal-halogen secondary bond and demonstrate that it is a weak noncovalent interaction comparable in strength to a hydrogen bond. These results provide insight into the origin of the specificity of the enzyme 2,6-dichlorohydroquinone 1,2-dioxygenase (PcpA), which is specific for ortho-dihalohydroquinone substrates and phenol inhibitors.
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Affiliation(s)
- Timothy E Machonkin
- Department of Chemistry, Whitman College , Walla Walla, Washington 99362, United States
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18
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Abubekerov M, Gianetti TL, Kunishita A, Arnold J. Synthesis and characterization of coordinatively unsaturated nickel(II) and manganese(II) alkyl complexes supported by the hydrotris(3-phenyl-5-methylpyrazolyl)borate (Tp(Ph,Me)) ligand. Dalton Trans 2013; 42:10525-32. [PMID: 23748480 DOI: 10.1039/c3dt51087e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The synthesis of several nickel(II) and manganese(II) alkyl complexes supported by hydrotris(3-phenyl-5-methylpyrazolyl)borate (Tp(Ph,Me)) ligand is reported. The metal halide complexes Tp(Ph,Me)MnCl(CH3CN) (1) and Tp(Ph,Me)NiCl (4) were used as precursors for synthesis of Tp(Ph,Me)MnCH2Si(Me)3 (2), Tp(Ph,Me)MnCH2Ph (3), Tp(Ph,Me)NiCH2Si(Me)3 (5) and Tp(Ph,Me)NiCH2Ph (6). The resulting Mn(II) and Ni(II) alkyl complexes, 2-3 and 5-6, were characterized by X-ray crystallography, NMR spectroscopy, and FT-IR spectroscopy. X-ray crystallographic analysis revealed distorted tetrahedral geometries for complexes 2-3 and 5 with a κ(3)-Tp(Ph,Me). Complex 6, on the other hand, was found to have a distorted square planar geometry with κ(2)-Tp(Ph,Me) and an η(3)-benzyl ligand. Transformations of 4 and Tp(Ph,Me)CoCl (10) via treatment with NaN3 to yield Tp(Ph,Me)NiN3 (11), Tp(Ph,Me)CoN3 (12), along with the synthesis of (Tp(Ph,Me))2Ni (8) and Tp(Ph,Me)NiCl(3-Ph-5MepzH) (9) are also reported.
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Affiliation(s)
- Mark Abubekerov
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
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Liang S, Wang H, Deb T, Petersen JL, Yee GT, Jensen MP. Structural and Spectroscopic Trends in a Series of Half-Sandwich Scorpionate Complexes. Inorg Chem 2012; 51:12707-19. [DOI: 10.1021/ic301409s] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Shengwen Liang
- Department of Chemistry and
Biochemistry, Ohio University, Athens,
Ohio 45701, United States
| | - Haoshuang Wang
- Department of Chemistry and
Biochemistry, Ohio University, Athens,
Ohio 45701, United States
| | - Tapash Deb
- Department of Chemistry and
Biochemistry, Ohio University, Athens,
Ohio 45701, United States
| | - Jeffrey L. Petersen
- C. Eugene Bennett Department
of Chemistry, West Virginia University,
Morgantown, West Virginia 26506, United States
| | - Gordon T. Yee
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg,
Virginia 24061, United States
| | - Michael P. Jensen
- Department of Chemistry and
Biochemistry, Ohio University, Athens,
Ohio 45701, United States
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