1
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Yang ES, García-Romero Á, Hu C, Fletcher J, Thomas CM, Goicoechea JM. Mixed-Valence Iron Complexes Containing End-On Bridging Cyaphide Ions. J Am Chem Soc 2024. [PMID: 39377638 DOI: 10.1021/jacs.4c11741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/09/2024]
Abstract
Iron cyanide compounds are among the oldest known synthetic coordination compounds, dating back to the early 18th century. By contrast, iron complexes of the cyaphide ion (C≡P-)─a heavy valence isoelectronic analog of the cyanide ion─are unknown. Herein we report the synthesis of highly stable mono- and bis-cyaphide complexes of iron(II), namely Fe(depe)2(Cl)(CP) and Fe(depe)2(CP)2 (depe = 1,2-bis(diethylphosphino)ethane). These iron(II) cyaphide complexes are capable of further coordination to iron(I) in a hitherto unknown linear coordination geometry, affording the conjugated multimetallic mixed-valence complexes [{Fe(depe)2}2(μ-CP)(N2)][BArF4]2 and [{Fe(depe)2}3(μ-CP)2][OTf]2.
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Affiliation(s)
- Eric S Yang
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Álvaro García-Romero
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Chenyang Hu
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Jess Fletcher
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Christine M Thomas
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Jose M Goicoechea
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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2
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Iwamoto T, Mitsubo T, Sakajiri K, Ishii Y. Vinylidene rearrangements of internal borylalkynes via 1,2-boryl migration. Dalton Trans 2024; 53:9715-9723. [PMID: 38804850 DOI: 10.1039/d4dt01042f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Vinylidene rearrangement of alkynes is a well-established and powerful method for alkyne transformations, while use of borylalkynes has remained largely unexplored. This paper describes vinylidene rearrangements of internal borylalkynes using a cationic ruthenium complex. This rearrangement is applicable to alkynes with both tri-(B(pin), B(dan)) and tetracoordinate (B(mida)) boryl groups, and the reaction rate is dramatically affected by the Lewis acidity of the boryl group. Mechanistic study revealed that the rearrangement proceeds via 1,2-boryl migration regardless of the coordination number of the boron center. The migration mode was elucidated by theoretical calculations to indicate that the migration of the tricoordinate boryl groups is an electrophilic process in contrast to the previous vinylidene rearrangements of internal alkynes with two carbon substituents.
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Affiliation(s)
- Takahiro Iwamoto
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
- Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Goshokaido-cho, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
| | - Takuya Mitsubo
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
| | - Kosuke Sakajiri
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
| | - Youichi Ishii
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
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3
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King AJ, Goicoechea JM. Ligand Centered Reactivity of a Transition Metal Bound Geometrically Constrained Phosphine. Chemistry 2024; 30:e202400624. [PMID: 38436534 DOI: 10.1002/chem.202400624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 02/29/2024] [Accepted: 03/04/2024] [Indexed: 03/05/2024]
Abstract
The electronic properties, coordination chemistry and reactivity of metal complexes of a planar (C2v symmetric) acridane-derived geometrically constrained phosphine, P(NNN), are described. On complexation to metal centers, the phosphine was found to adopt a distorted trigonal pyramidal structure with a high barrier to pyramidal inversion (22.3 kcal/mol at 298 K for Au[P(NNN)]Cl). Spectroscopic data and theoretical calculations carried out at the density functional level of theory indicate that P(NNN) is a moderate σ-donor, with significant π-acceptor properties. Despite the distortion undergone by the phosphorus atom on coordination to metal centers, the P(NNN) ligand retains its ability to react with small molecule substrates with polar E-H bonds (MeOH, NH2Ph, NH3). It does so in a concerted fashion across one of the P-N bonds, and reversibly in the case of amine substrates. This cooperative bond activation chemistry may ultimately prove beneficial in catalysis.
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Affiliation(s)
- Aaron J King
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12, Mansfield Rd., Oxford, OX1 3TA, U.K
| | - Jose M Goicoechea
- Department of Chemistry, Indiana University, 800 East Kirkwood Ave., Bloomington, Indiana, 47405, U.S.A
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4
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Delaney AR, Kroeger AA, Coote ML, Colebatch AL. Oxidative Addition and β-Hydride Elimination by a Macrocyclic Dinickel Complex: Observing Bimetallic Elementary Reactions. Chemistry 2023; 29:e202302366. [PMID: 37641804 DOI: 10.1002/chem.202302366] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 08/31/2023]
Abstract
The dinickel(I) complex Ni2 (tBu PONNOPONNO), featuring a planar macrocyclic diphosphoranide ligand tBu PONNOPONNO, offers a unique architectural platform for observing bimetallic elementary reactions. Oxidative addition reactions of alkyl halides produce dinickel(II) complexes of the type Ni2 (μ-R)(μ-X)(tBu PONNOPONNO). However, when R=Et β-hydride elimination is observed to form a dinickel monohydride, with the rate dependent on the nature of X. DFT studies suggest a new mechanism for bimetallic β-hydride elimination, where the rate dependence arises from the steric pressure imposed by the X group on the opposing trans face of the dinickel macrocycle. This work enhances understanding of bimetallic elementary reactions, particularly β-hydride elimination, which have not been well-explored for dinuclear systems.
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Affiliation(s)
- Andie R Delaney
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Asja A Kroeger
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
- Institute for Nanoscale Science & Technology, Flinders University, Adelaide, South Australia, 5042, Australia
| | - Michelle L Coote
- Institute for Nanoscale Science & Technology, Flinders University, Adelaide, South Australia, 5042, Australia
| | - Annie L Colebatch
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
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5
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Bisht SK, Sharma D, Kannan R, Rajeshkumar T, Maron L, Venugopal A. Quest for Active Species in Al/B-Catalyzed CO 2 Hydrosilylation. Inorg Chem 2023; 62:18543-18552. [PMID: 37906233 DOI: 10.1021/acs.inorgchem.3c02771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
We demonstrate the catalytic role of aluminum and boron centers in aluminum borohydride [(2-Me2CH2C6H4)(C6H5)Al(μ-H)2B(C6H5)2] (6) during carbon dioxide (CO2) hydrosilylation. Preliminary investigations into CO2 reduction using [(2-Me2NCH2C6H4)(H)Al(μ-H)]2 (1) and [Ph3C][B(3,5-C6H3Cl2)4] (2) in the presence of Et3SiH and PhSiH3 resulted in CH2(OSiR3)2 and CH3OSiR3, which serve as formaldehyde and methanol surrogates, respectively. In pursuit of identifying the active catalytic species, three compounds, B(3,5-C6H3Cl2)3 (3), [(2-Me2NCH2C6H4)(3,5-C6H3Cl2)Al(μ-H)2B(3,5-C6H3Cl2)2] (4), and [(2-Me2NCH2C6H4)2Al(THF)][B(3,5-C6H3Cl2)4] (5), were isolated. Among compounds 2-5, the highest catalytic conversion was achieved by 4. Further, 4 and 6 were prepared in a straightforward method by treating 1 with 3 and BPh3, respectively. 6 was found to be in equilibrium with 1 and BPh3, thus making the catalytic process of 6 more efficient than that of 4. Computational investigations inferred that CO2 reduction occurs across the Al-H bond, while Si-H activation occurs through a concerted mechanism involving an in situ generated aluminum formate species and BPh3.
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Affiliation(s)
- Sheetal Kathayat Bisht
- School of Chemistry, Indian Institute of Science Education and Research (IISER) Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India
| | - Deepti Sharma
- School of Chemistry, Indian Institute of Science Education and Research (IISER) Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India
| | - Ramkumar Kannan
- School of Chemistry, Indian Institute of Science Education and Research (IISER) Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India
| | - Thayalan Rajeshkumar
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, Toulouse, Cedex 4 31077, France
| | - Laurent Maron
- Laboratoire de Physique et Chimie des Nano-objets, Institut National des Sciences Appliquées, Toulouse, Cedex 4 31077, France
| | - Ajay Venugopal
- School of Chemistry, Indian Institute of Science Education and Research (IISER) Thiruvananthapuram, Vithura, Thiruvananthapuram 695551, India
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6
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Nakanishi K, Lugo-Fuentes LI, Manabe J, Guo R, Kikkawa S, Yamazoe S, Komaguchi K, Kume S, Szczepanik DW, Solà M, Jimenez-Halla JOC, Nishihara S, Kubo K, Nakamoto M, Yamamoto Y, Mizuta T, Shang R. Redox Activity of Ir III Complexes with Multidentate Ligands Based on Dipyrido-Annulated N-Heterocyclic Carbenes: Access to High Valent and High Spin State with Carbon Donors. Chemistry 2023; 29:e202302303. [PMID: 37553318 DOI: 10.1002/chem.202302303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 08/10/2023]
Abstract
Synthetic strategies to access high-valent iridium complexes usually require use of π donating ligands bearing electronegative atoms (e. g. amide or oxide) or σ donating electropositive atoms (e. g. boryl or hydride). Besides the η5 -(methyl)cyclopentadienyl derivatives, high-valent η1 carbon-ligated iridium complexes are challenging to synthesize. To meet this challenge, this work reports the oxidation behavior of an all-carbon-ligated anionic bis(CCC-pincer) IrIII complex. Being both σ and π donating, the diaryl dipyrido-annulated N-heterocyclic carbene (dpa-NHC) IrIII complex allowed a stepwise 4e- oxidation sequence. The first 2e- oxidation led to an oxidative coupling of two adjacent aryl groups, resulting in formation of a cationic chiral IrIII complex bearing a CCCC-tetradentate ligand. A further 2e- oxidation allowed isolation of a high-valent tricationic complex with a triplet ground state. These results close a synthetic gap for carbon-ligated iridium complexes and demonstrate the electronic tuning potential of organic π ligands for unusual electronic properties.
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Affiliation(s)
- Kazuki Nakanishi
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Leonardo I Lugo-Fuentes
- Department of Chemistry, Division of Natural and Exact Sciences, University of Guanajuato, Campus Gto, Noria Alta s/n, 36050, Guanajuato, Mexico
| | - Jun Manabe
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Ronghao Guo
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Soichi Kikkawa
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan
| | - Seiji Yamazoe
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan
| | - Kenji Komaguchi
- Department of Applied Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, 739-8527, Japan
| | - Shoko Kume
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Dariusz W Szczepanik
- K. Guminski Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa, 2, 30-387, Kraków, Poland
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany, 69, 17003, Girona, Catalonia, Spain
| | - J Oscar C Jimenez-Halla
- Department of Chemistry, Division of Natural and Exact Sciences, University of Guanajuato, Campus Gto, Noria Alta s/n, 36050, Guanajuato, Mexico
| | - Sadafumi Nishihara
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Kazuyuki Kubo
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Masaaki Nakamoto
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Yohsuke Yamamoto
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Tsutomu Mizuta
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
| | - Rong Shang
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 739-8526, Japan
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7
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Cross MJ, Brodie CN, Crivoi DG, Goodall JC, Ryan DE, Martínez‐Martínez AJ, Johnson A, Weller AS. Dehydropolymerization of Amine-Boranes using Bis(imino)pyridine Rhodium Pre-Catalysis: σ-Amine-Borane Complexes, Nanoparticles, and Low Residual-Metal BN-Polymers that can be Chemically Repurposed. Chemistry 2023; 29:e202302110. [PMID: 37530441 PMCID: PMC10947130 DOI: 10.1002/chem.202302110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 08/03/2023]
Abstract
The sigma amine-borane complexes [Rh(L1)(η2 :η2 -H3 B⋅NRH2 )][OTf] (L1=2,6-bis-[1-(2,6-diisopropylphenylimino)ethyl]pyridine, R=Me, Et, n Pr) are described, alongside [Rh(L1)(NMeH2 )][OTf]. Using R=Me as a pre-catalyst (1 mol %) the dehydropolymerization of H3 B ⋅ NMeH2 gives [H2 BNMeH]n selectively. Added NMeH2 , or the direct use of [Rh(L1)(NMeH2 )][OTf], is required for initiation of catalysis, which is suggested to operate through the formation of a neutral hydride complex, Rh(L1)H. The formation of small (1-5 nm) nanoparticles is observed at the end of catalysis, but studies are ambiguous as to whether the catalysis is solely nanoparticle promoted or if there is a molecular homogeneous component. [Rh(L1)(NMeH2 )][OTf] is shown to operate at 0.025 mol % loadings on a 2 g scale of H3 B ⋅ NMeH2 to give polyaminoborane [H2 BNMeH]n [Mn =30,900 g/mol, Ð=1.8] that can be purified to a low residual [Rh] (6 μg/g). Addition of Na[N(SiMe3 )2 ] to [H2 BNMeH]n results in selective depolymerization to form the eee-isomer of N,N,N-trimethylcyclotriborazane [H2 BNMeH]3 : the chemical repurposing of a main-group polymer.
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Affiliation(s)
| | | | - Dana G. Crivoi
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
| | | | - David E. Ryan
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
| | - Antonio J. Martínez‐Martínez
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
- Supramolecular Organometallic and Main Group Chemistry Laboratory CIQSO-Center for Research in Sustainable Chemistry and Department of ChemistryUniversity of HuelvaCampus El Carmen21007HuelvaSpain
| | - Alice Johnson
- Department of ChemistryUniversity of OxfordOxfordOX1 3TAUK
- Department of Biosciences and ChemistrySheffield Hallam UniversityHoward StSheffieldS1 1WBUK
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8
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McMillion ND, Bruch QJ, Chen CH, Hasanayn F, Miller AJM. Synthesis and bonding analysis of pentagonal bipyramidal rhenium carboxamide oxo complexes. Dalton Trans 2023; 52:15115-15123. [PMID: 37814941 DOI: 10.1039/d3dt02617e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Seven-coordinate rhenium oxo complexes supported by a tetradentate bipyridine carboxamide/carboxamidate ligand are reported. The neutral dicarboxamide H2Phbpy-da ligand initially coordinates in an L4 (ONNO) fashion to an octahedral rhenium oxo precursor, yielding a seven-coordinate rhenium oxo complex. Subsequent deprotonation generates a new oxo complex featuring the dianionic (L2X2) carboxamidate (NNNN) form of the ligand. Computational studies provide insight into the relative stability of possible linkage isomers upon deprotonation. Structural studies and molecular orbital theory are employed to rationalize the relative isomer stability and provide insight into the rhenium-oxo bond order.
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Affiliation(s)
- Noah D McMillion
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
| | - Quinton J Bruch
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
| | - Chun-Hsing Chen
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
| | - Faraj Hasanayn
- Department of Chemistry, American University of Beirut, Beirut 1107 2020, Lebanon.
| | - Alexander J M Miller
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, USA.
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9
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Acosta-Calle S, Miller AJM. Tunable and Switchable Catalysis Enabled by Cation-Controlled Gating with Crown Ether Ligands. Acc Chem Res 2023; 56:971-981. [PMID: 36977400 DOI: 10.1021/acs.accounts.3c00056] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
ConspectusCatalysis has become an essential tool in science and technology, impacting the discovery of pharmaceuticals, the manufacture of commodity chemicals and plastics, the production of fuels, and much more. In most cases, a particular catalyst is optimized to mediate a particular reaction, continually producing a desired product at a given rate. There is enormous opportunity in developing catalysts that are dynamic, capable of responding to a change in the environment to alter structure and function. Controlled catalysis, in which the activity or selectivity of a catalytic reaction can be adjusted through an external stimulus, offers opportunities for innovation in catalysis. Catalyst discovery could be simplified if a single thoughtfully designed complex could work synergistically with additives to optimize performance rather than trying a multitude of different metal/ligand combinations. Temporal control could be gained to facilitate the execution of multiple reactions in the same flask, for example, by activating one catalyst and deactivating another to avoid incompatibilities. Selectivity switching could enable copolymer synthesis with well-defined chemical and material properties. These applications might sound futuristic for synthetic catalysts, but in nature, such a degree of controlled catalysis is commonplace. For example, allosteric interactions and/or feedback loops modulate enzymatic activity to enable complex small-molecule synthesis and sequence-defined polymerization reactions in complex mixtures containing many catalytic sites. In many cases, regulation is achieved by "gating" substrate access to the active site. Fundamental advances in catalyst design are needed to better understand the factors that enable controlled catalysis in the arena of synthetic chemistry, particularly in achieving substrate gating outside of macromolecular environments. In this Account, the development of design principles for achieving cation-controlled catalysis is described. The guiding hypothesis was that gating substrate access to a catalyst site could be achieved by controlling the dynamics of a hemilabile ligand through secondary Lewis acid/base and/or cation-dipole interactions. To enforce such interactions, catalysts sitting at the interface of organometallic catalysis and supramolecular chemistry were designed. A macrocyclic crown ether was incorporated into a robust organometallic pincer ligand, and these "pincer-crown ether" ligands have been explored in catalysis. Complementary studies of controlled catalysis and detailed mechanistic analysis guided the development of iridium, nickel, and palladium pincer-crown ether catalysts capable of substrate gating. Toggling the gate between open and closed states leads to switchable catalysis, where cation addition/removal changes the turnover frequency or the product selectivity. Varying the degree of gating leads to tunable catalysis, where the activity can be tuned based on the identity and amount of salt added. Research has focused on reactions of alkenes, particularly isomerization reactions, which has in turn led to design principles for cation-controlled catalysts.
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Affiliation(s)
- Sebastian Acosta-Calle
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Alexander J M Miller
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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10
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Netam KD, Pal AK, Nethaji M, Jagirdar BR. Agostic interaction versus small molecule binding in [RuH(CO)(PPhNiPrPPh)]BAr4F complex. J Organomet Chem 2023. [DOI: 10.1016/j.jorganchem.2023.122693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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11
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Poole EW, Bustos I, Hood TM, Smart JE, Chaplin AB. Iridium complexes of an ortho-trifluoromethylphenyl substituted PONOP pincer ligand. Dalton Trans 2023; 52:1096-1104. [PMID: 36602231 PMCID: PMC9872493 DOI: 10.1039/d2dt03608h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthesis and iridium coordination chemistry of a new pyridine-based phosphinito pincer ligand 2,6-(ArF2PO)2C5H3N (PONOP-ArF; ArF = 2-(CF3)C6H4) are described, where the P-donors have ortho-trifluoromethylphenyl substituents. The iridium(III) 2,2'-biphenyl (biph) derivative [Ir(PONOP-ArF)(biph)Cl] was obtained by reaction with [Ir(biph)(COD)Cl]2 (COD = 1,5-cyclooctadiene) and subsequent halide ion abstraction enabled isolation of [Ir(PONOP-ArF)(biph)]+ which features an Ir ← F-C bonding interaction in the solid state. Hydrogenolysis of the biphenyl ligand and formation of [Ir(PONOP-ArF)(H)2]+ was achieved by prolonged reaction of [Ir(PONOP-ArF)(biph)]+ with dihydrogen. This transformation paved the way for isolation and crystallographic characterisation of low valent iridium derivatives through treatment of the dihydride with tert-butylethylene (TBE). The iridium(I) π-complex [Ir(PONOP-ArF)(TBE)]+ is thermally stable but substitution of TBE can be achieved by reaction with carbon monoxide. The solid-state structure of the mono-carbonyl product [Ir(PONOP-ArF)(CO)]+ is notable for an intermolecular anagostic interaction between the metal centre and a pentane molecule which co-crystallises within a cleft defined by two aryl phosphine substituents.
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Affiliation(s)
- Ethan W. Poole
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
| | - Itxaso Bustos
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK,Facultad de Química de San Sebastián, Universidad del País Vasco (UPV/EHU)Apdo. 107220080 San SebastiánSpain
| | - Thomas M. Hood
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
| | - Jennifer E. Smart
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
| | - Adrian B. Chaplin
- Department of Chemistry, University of WarwickGibbet Hill RoadCoventry CV4 7ALUK
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12
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Bajo S, Theulier CA, Campos J. Mechanistic Investigations on Hydrogenation, Isomerization and Hydrosilylation Reactions Mediated by a Germyl-Rhodium System. ChemCatChem 2022; 14:e202200157. [PMID: 36032040 PMCID: PMC9401076 DOI: 10.1002/cctc.202200157] [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: 01/30/2022] [Revised: 05/09/2022] [Indexed: 11/07/2022]
Abstract
We recently disclosed a dehydrogenative double C-H bond activation reaction in the unusual pincer-type rhodium-germyl complex [(ArMes)2ClGeRh] (ArMes=C6H3-2,6-(C6H2-2,4,6-Me3)2). Herein we investigate the catalytic applications of this Rh/Ge system in several transformations, namely trans-semihydrogenation of internal alkynes, trans-isomerization of olefins and hydrosilylation of alkynes. We have compared the activity and selectivity of this catalyst against other common rhodium precursors, as well as related sterically hindered rhodium complexes, being the one with the germyl fragment superior in terms of selectivity towards E-isomers. To increase this selectivity, a tandem catalytic protocol that incorporates the use of a heterogeneous catalyst for the trans-semihydrogenation of internal alkynes has been devised. Kinetic mechanistic investigations provide important information regarding the individual catalytic cycles that comprise the overall trans-semihydrogenation of internal alkynes.
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Affiliation(s)
- Sonia Bajo
- Instituto de Investigaciones Químicas (IIQ)Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA)Consejo Superior de Investigaciones Científicas (CSIC) and University of Sevilla.Avenida Américo Vespucio 4941092SevillaSpain
| | - Cyril A. Theulier
- Instituto de Investigaciones Químicas (IIQ)Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA)Consejo Superior de Investigaciones Científicas (CSIC) and University of Sevilla.Avenida Américo Vespucio 4941092SevillaSpain
| | - Jesús Campos
- Instituto de Investigaciones Químicas (IIQ)Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA)Consejo Superior de Investigaciones Científicas (CSIC) and University of Sevilla.Avenida Américo Vespucio 4941092SevillaSpain
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13
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Garduño JA, Glueck DS, Hernandez RE, Figueroa JS, Rheingold AL. Protonolysis of the [B(Ar F) 4] − Anion Mediated by Nucleophile/Electrophile/Water Cooperativity in a Platinum–PMe 2OH Complex. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jorge A. Garduño
- Department of Chemistry, Dartmouth College, 6128 Burke Laboratory, Hanover, New Hampshire 03755, United States
| | - David S. Glueck
- Department of Chemistry, Dartmouth College, 6128 Burke Laboratory, Hanover, New Hampshire 03755, United States
| | - Ritchie E. Hernandez
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Joshua S. Figueroa
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Arnold L. Rheingold
- Department of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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14
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Hadlington TJ, Keil PM. Protonation of Hydrido‐Tetrylenes: H2 Elimination vs. Tetrylium Cation Formation. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | - Philip Maximillian Keil
- Technical University Munich: Technische Universitat Munchen Department of Chemistry Lichtenberg Str 4 85748 Garching GERMANY
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15
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Itabashi T, Arashiba K, Kuriyama S, Nishibayashi Y. Reactivity of molybdenum-nitride complex bearing pyridine-based PNP-type pincer ligand toward carbon-centered electrophiles. Dalton Trans 2022; 51:1946-1954. [PMID: 35023535 DOI: 10.1039/d1dt03952k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A molybdenum-nitride complex bearing a pyridine-based PNP-type pincer ligand derived from dinitrogen is reacted with various kinds of carbon-centered electrophiles to functionalize the nitride ligand in the molybdenum complex. Methylation with MeOTf and acylation with diphenylacetyl chloride of the nitride complex afford the corresponding imide complexes via a carbon-nitrogen bond formation. In the case of reactions with phenylisocyanate and diphenylketene, the PNP ligand works as a non-innocent ligand to form the corresponding ureate and acylimide complexes, respectively. These newly synthesized complexes are characterized by X-ray analysis. As a further transformation of the prepared imide complexes, hydrolysis of the molybdenum-acylimide complex proceeds to give the corresponding amide as an organonitrogen compound together with the corresponding molybdenum-oxo complex. This result indicates that the nitrogen molecule is converted into organic amide mediated by the molybdenum-nitride complex.
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Affiliation(s)
- Takayuki Itabashi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Kazuya Arashiba
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Shogo Kuriyama
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
| | - Yoshiaki Nishibayashi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
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16
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Townrow OPE, Duckett SB, Weller AS, Goicoechea JM. Zintl cluster supported low coordinate Rh( i) centers for catalytic H/D exchange between H 2 and D 2. Chem Sci 2022; 13:7626-7633. [PMID: 35872810 PMCID: PMC9242017 DOI: 10.1039/d2sc02552c] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 06/08/2022] [Indexed: 12/19/2022] Open
Abstract
We describe the synthesis of the coordinatively unsaturated Zintl clusters [Rh(L){η3-Ge9(Hyp)3}] (where L = PMe3, PPh3, IMe4 or [W(Cp)2H2]). These species are active catalysts in H/D exchange and C–H bond activation reactions.
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Affiliation(s)
- Oliver P. E. Townrow
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | | | | | - Jose M. Goicoechea
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK
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17
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Delaney AR, Yu LJ, Coote ML, Colebatch AL. Synthesis of an expanded pincer ligand and its bimetallic coinage metal complexes. Dalton Trans 2021; 50:11909-11917. [PMID: 34374394 DOI: 10.1039/d1dt01741a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An expanded pincer ligand tBu-PONNOP (2,7-bis(di-tert-butylphosphinito)-1,8-naphthyridine) has been synthesised and its coordination to coinage metals has been studied. Bimetallic complexes were produced with metal halide salts of the type [M2X2(tBu-PONNOP)] (X = Cl, M = Au, Ag, Cu; X = I, M = Cu) with a varying degree of interaction with the naphthyridyl backbone in the order Au < Ag < Cu. The salts [Ag2(tBu-PONNOP)2][BArF4]2 (ArF = 3,5-C6H3(CF3)2) and [Ag2(NCMe)2(tBu-PONNOP)]X2 (X = BArF4, PF6) were prepared, which may serve as a source of tBu-PONNOP via transmetallation.
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Affiliation(s)
- Andie R Delaney
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia.
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18
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Chambenahalli R, Bhargav RM, McCabe KN, Andrews AP, Ritter F, Okuda J, Maron L, Venugopal A. Cationic Zinc Hydride Catalyzed Carbon Dioxide Reduction to Formate: Deciphering Elementary Reactions, Isolation of Intermediates, and Computational Investigations. Chemistry 2021; 27:7391-7401. [PMID: 33459452 DOI: 10.1002/chem.202005392] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/11/2021] [Indexed: 01/06/2023]
Abstract
Zinc has been an element of choice for carbon dioxide reduction in recent years. Zinc compounds have been showcased as catalysts for carbon dioxide hydrosilylation and hydroboration. The extent of carbon dioxide reduction can depend on various factors, including electrophilicity at the zinc center and the denticity of the ancillary ligands. In a few cases, the addition of Lewis acids to zinc hydride catalysts markedly influences carbon dioxide reduction. These factors have been investigated by exploring elementary reactions of carbon dioxide hydrosilylation and hydroboration by using cationic zinc hydrides bearing tetradentate tris[2-(dimethylamino)ethyl]amine and tridentate N,N,N',N'',N''-pentamethyldiethylenetriamine in the presence of triphenylborane and tris(pentafluorophenyl)borane.
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Affiliation(s)
- Raju Chambenahalli
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Vithura, Thiruvananthapuram, 695551, India
| | - R M Bhargav
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Vithura, Thiruvananthapuram, 695551, India
| | - Karl N McCabe
- LPCNO, UMR 5215, Université de Toulouse-CNRS, INSA, UPS, 31077, Toulouse, France
| | - Alex P Andrews
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Vithura, Thiruvananthapuram, 695551, India
| | - Florian Ritter
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056, Aachen, Germany
| | - Jun Okuda
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056, Aachen, Germany
| | - Laurent Maron
- LPCNO, UMR 5215, Université de Toulouse-CNRS, INSA, UPS, 31077, Toulouse, France
| | - Ajay Venugopal
- School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram, Vithura, Thiruvananthapuram, 695551, India
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19
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Hood TM, Chaplin AB. Synthesis and reactivity of iridium complexes of a macrocyclic PNP pincer ligand. Dalton Trans 2021; 50:2472-2482. [PMID: 33511383 DOI: 10.1039/d0dt04303f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Having recently reported on the synthesis and rhodium complexes of the novel macrocyclic pincer ligand PNP-14, which is derived from lutidine and features terminal phosphine donors trans-substituted with a tetradecamethylene linker (Dalton Trans., 2020, 49, 2077-2086 and Dalton Trans., 2020, 49, 16649-16652), we herein describe our findings critically examining the chemistry of iridium homologues. The five-coordinate iridium(i) and iridium(iii) complexes [Ir(PNP-14)(η2:η2-cyclooctadiene)][BArF4] and [Ir(PNP-14)(2,2'-biphenyl)][BArF4] are readily prepared and shown to be effective precursors for the generation of iridium(iii) dihydride dihydrogen, iridium(i) bis(ethylene), and iridium(i) carbonyl derivatives that highlight important periodic trends by comparison to rhodium counterparts. Reaction of [Ir(PNP-14)H2(H2)][BArF4] with 3,3-dimethylbutene induced triple C-H bond activation of the methylene chain, yielding an iridium(iii) allyl hydride derivative [Ir(PNP-14*)H][BArF4], whilst catalytic homocoupling of 3,3-dimethylbutyne into Z-tBuC[triple bond, length as m-dash]CCHCHtBu could be promoted at RT by [Ir(PNP-14)(η2:η2-cyclooctadiene)][BArF4] (TOFinitial = 28 h-1). The mechanism of the latter is proposed to involve formation and direct reaction of a vinylidene derivative with HC[triple bond, length as m-dash]CtBu outside of the macrocyclic ring and this suggestion is supported experimentally by isolation and crystallographic characterisation of a catalyst deactivation product.
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Affiliation(s)
- Thomas M Hood
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
| | - Adrian B Chaplin
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
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20
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Sinclair MJ, Chaplin AB. Oxidative ring expansion of a low-coordinate palladacycle: Synthesis of a robust T-shaped alkylpalladium(II) complex. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2020.119948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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21
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Kynman AE, Lau S, Dowd SO, Krämer T, Chaplin AB. Oxidative Addition of Biphenylene and Chlorobenzene to a Rh(CNC) Complex. Eur J Inorg Chem 2020; 2020:3899-3906. [PMID: 33328794 PMCID: PMC7702176 DOI: 10.1002/ejic.202000780] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Indexed: 01/10/2023]
Abstract
The synthesis and organometallic chemistry of rhodium(I) complex [Rh(CNC-Me)(SOMe2)][BArF 4], featuring NHC-based pincer and labile dimethyl sulfoxide ligands, is reported. This complex reacts with biphenylene and chlorobenzene to afford products resulting from selective C-C and C-Cl bond activation, [Rh(CNC-Me)(2,2'-biphenyl)(OSMe2)][BArF 4] and [Rh(CNC-Me)(Ph)Cl(OSMe2)][BArF 4], respectively. A detailed DFT-based computational analysis indicates that C-H bond oxidative addition of these substrates is kinetically competitive, but in all cases endergonic: contrasting the large thermodynamic driving force calculated for insertion of the metal into the C-C and C-Cl bonds, respectively. Under equivalent conditions the substrates are not activated by the phosphine-based pincer complex [Rh(PNP-iPr)(SOMe2)][BArF 4].
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Affiliation(s)
- Amy E. Kynman
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - Samantha Lau
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
| | - Sean O. Dowd
- Department of ChemistryMaynooth UniversityCo. KildareMaynoothIreland
| | - Tobias Krämer
- Department of ChemistryMaynooth UniversityCo. KildareMaynoothIreland
- Hamilton InstituteMaynooth UniversityCo. KildareMaynoothIreland
| | - Adrian B. Chaplin
- Department of ChemistryUniversity of WarwickGibbet Hill RoadCoventryCV4 7ALUK
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22
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Dodge HM, Kita MR, Chen CH, Miller AJM. Identifying and Evading Olefin Isomerization Catalyst Deactivation Pathways Resulting from Ion-Tunable Hemilability. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03784] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Henry M. Dodge
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Matthew R. Kita
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Chun-Hsing Chen
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Alexander J. M. Miller
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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23
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Malinowski PJ, Jaroń T, Domańska M, Slattery JM, Schmitt M, Krossing I. Building blocks for the chemistry of perfluorinated alkoxyaluminates [Al{OC(CF 3) 3} 4] -: simplified preparation and characterization of Li +-Cs +, Ag +, NH 4+, N 2H 5+ and N 2H 7+ salts. Dalton Trans 2020; 49:7766-7773. [PMID: 32329763 DOI: 10.1039/d0dt00592d] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Advanced weakly coordinating anions (WCAs) significantly facilitate synthesis of various exotic chemical compounds and novel, potentially useful materials. One of such anions - [Al{OC(CF3)3}4]-, denoted [Al(ORF)4]-, appears particularly convenient, as it can be easily prepared from the commercially available alanates and HOC(CF3)3. Here we present a thorough characterization of a series of solvent-free M[Al(ORF)4] salts, M = Li-Cs, Ag, NH4, N2H5 and N2H7, and related compounds of monovalent cations, which are crucial starting materials for further work with these species. Notably, the corresponding synthetic protocols are updated by an improved method for fast, facile and easily scalable synthesis of Li[Al(ORF)4], which remains the most useful primary source of the anion. The physico-chemical properties of these salts including crystal structures, thermal stability by TG/DSC, vibrational spectra as well as solubility are discussed in a systematic fashion.
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24
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Alvarez S. Coordinating Ability of Anions, Solvents, Amino Acids, and Gases towards Alkaline and Alkaline-Earth Elements, Transition Metals, and Lanthanides. Chemistry 2020; 26:4350-4377. [PMID: 31910294 DOI: 10.1002/chem.201905453] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Indexed: 02/06/2023]
Abstract
After briefly reviewing the applications of the coordination ability indices proposed earlier for anions and solvents toward transition metals and lanthanides, a new analysis of crystal structures is applied now to a much larger number of coordinating species: anions (including those that are present in ionic solvents), solvents, amino acids, gases, and a sample of neutral ligands. The coordinating ability towards s-block elements is now also considered. The effect of several factors on the coordinating ability will be discussed: (a) the charge of an anion, (b) the chelating nature of anions and solvents, (c) the degree of protonation of oxo-anions, carboxylates and amino carboxylates, and (d) the substitution of hydrogen atoms by methyl groups in NH3 , ethylenediamine, benzene, ethylene, pyridine and aldehydes. Hit parades of solvents and anions most commonly used in the areas of transition metal, s-block and lanthanide chemistry are deduced from the statistics of their presence in crystal structures.
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Affiliation(s)
- Santiago Alvarez
- Department de Química Inorgànica i Orgànica, Secció de Química Inorgànica and, Institut de Química Teòrica i Computacional, Universitat de Barcelona, Martí i Franquès, 1-11, 08028, Barcelona, Spain
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25
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Hood TM, Gyton MR, Chaplin AB. Synthesis and rhodium complexes of macrocyclic PNP and PONOP pincer ligands. Dalton Trans 2020; 49:2077-2086. [PMID: 31912067 DOI: 10.1039/c9dt04474d] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of macrocyclic variants of commonly employed phosphine-based pincer ligands derived from lutidine (PNP-14) and 2,6-dihydroxypyridine (PONOP-14) is described, where the P-donors are trans-substituted with a tetradecamethylene linker. This was accomplished using an eight-step procedure involving borane protection, ring-closing olefin metathesis, chromatographic separation from the cis-substituted diastereomers, and borane deprotection. The rhodium coordination chemistry of these ligands has been explored, aided by the facile synthesis of 2,2'-biphenyl (biph) adducts [Rh(PNP-14)(biph)][BArF4] and [Rh(PONOP-14)(biph)][BArF4] (ArF = 3,5-(CF3)2C6H3). Subsequent hydrogenolysis enabled generation of dihydrogen, ethylene and carbonyl derivatives; notably the ν(CO) bands of the carbonyl complexes provide a means to compare the donor properties of the new pincer ligands with established acyclic congeners.
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Affiliation(s)
- Thomas M Hood
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
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26
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Lacroix MR, Liu Y, Strauss SH. Hydrated Metal Ion Salts of the Weakly Coordinating Fluoroanions PF 6-, TiF 62-, B 12F 122-, Ga(C 2F 5) 4-, B(3,5-C 6H 3(CF 3) 2) 4-, and Al(OC(CF 3) 3) 4-. In Search of the Weakest HOH···F Hydrogen Bonds. Inorg Chem 2019; 58:14900-14911. [PMID: 31617354 DOI: 10.1021/acs.inorgchem.9b02646] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
FTIR spectra of microcrystalline samples of 11 metal ion salt hydrates of a variety of weakly coordinating fluoroanions are reported. The compounds studied were Li(H2O)4(Al(OC(CF3)3)4), Li(H2O)(B(3,5-C6H3(CF3)2)4), Li(H2O)n(Ga(C2F5)4), Li(H2O)(PF6), Li2(H2O)2(TiF6), Li2(H2O)4(B12F12), Na(H2O)(PF6), Na2(H2O)2(B12F12), K2(H2O)2(B12F12), Rb2(H2O)2(B12F12), Cs2(H2O)(B12F12), and their partially or completely deuterated isotopologs and isotopomers. The O-D···F hydrogen bonds in Li(HOD)(H2O)3(Al(OC(CF3)3)4) (ν(OD) = 2706 cm-1), Li(HOD)(B(3,5-C6H3(CF3)2)4) (ν(OD) = 2705 cm-1), and Li(HOD)(H2O)n(Ga(C2F5)4) (ν(OD) = 2697 cm-1) rival HOD absorbed in polyvinylidene difluoride (ν(OD) = 2696 cm-1) and HOD···FCH3 in a frozen Ar matrix (ν(OD) = 2685 cm-1) for the weakest hydrogen bonds between a water molecule and an F atom in any compound. As weak as they are, minor differences in O-H···F hydrogen bonds in the same fluoroanion salt can be distinguished spectroscopically. Uncoupled HOD molecules in asymmetric F···HOD···F' hydrogen bonding environments in Rb+, Cs+, Mg2+, and Co2+ hydrates of B12F122- gave rise to two observable ν(OD) bands even though the two R(O···F) distances differ by only 0.010(4) Å (Mg2+), 0.033(2) Å (Co2+), 0.074(4) Å (Rb+), and 0.106(6) Å (Cs+). A plot of ν(OD) for hydrates with a single uncoupled HOD molecule per metal ion (e.g., Li(HOD)(H2O)3(Al(OC(CF3)3)4)) vs R(O···F) distance from single-crystal X-ray or neutron diffraction structures was prepared. The ν(OD) values range from 2305 to 2706 cm-1 and the R(O···F) distances range from 2.58 to 3.17 Å. The plot consists of 53 {ν(OD), R(O···F)} data points, 23 of which are new and have ν(OD) > 2600 cm-1, in contrast to a 1994 ν(OD) vs R(O···F) plot with 28 data points, none of which had ν(OD) > 2600 cm-1. There is a clear and significant difference between the new ν(OD) vs R(O···F) plot and a literature ν(OD) vs R(O···O) plot for hydrates containing O-D···O hydrogen bonds. For a given ν(OD) stretching frequency, the exponential regression curves show that R(O···F) is typically 0.1-0.2 Å shorter than R(O···O), in harmony with the lower basicity and smaller size of F atoms vs O atoms.
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Affiliation(s)
- Matthew R Lacroix
- Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523 , United States
| | - Yong Liu
- Department of Chemistry , University of Colorado at Denver , Denver , Colorado 80217 , United States
| | - Steven H Strauss
- Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523 , United States
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27
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Spearing-Ewyn EAK, Beattie NA, Colebatch AL, Martinez-Martinez AJ, Docker A, Boyd TM, Baillie G, Reed R, Macgregor SA, Weller AS. The role of neutral Rh(PONOP)H, free NMe 2H, boronium and ammonium salts in the dehydrocoupling of dimethylamine-borane using the cationic pincer [Rh(PONOP)(η 2-H 2)] + catalyst. Dalton Trans 2019; 48:14724-14736. [PMID: 31538996 DOI: 10.1039/c9dt03358k] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The σ-amine-borane pincer complex [Rh(PONOP)(η1-H3B·NMe3)][BArF4] [2, PONOP = κ3-NC5H3-2,6-(OPtBu2)2] is prepared by addition of H3B·NMe3 to the dihydrogen precursor [Rh(PONOP)(η2-H2)][BArF4], 1. In a similar way the related H3B·NMe2H complex [Rh(PONOP)(η1-H3B·NMe2H)][BArF4], 3, can be made in situ, but this undergoes dehydrocoupling to reform 1 and give the aminoborane dimer [H2BNMe2]2. NMR studies on this system reveal an intermediate neutral hydride forms, Rh(PONOP)H, 4, that has been prepared independently. 1 is a competent catalyst (2 mol%, ∼30 min) for the dehydrocoupling of H3B·Me2H. Kinetic, mechanistic and computational studies point to the role of NMe2H in both forming the neutral hydride, via deprotonation of a σ-amine-borane complex and formation of aminoborane, and closing the catalytic cycle by reprotonation of the hydride by the thus-formed dimethyl ammonium [NMe2H2]+. Competitive processes involving the generation of boronium [H2B(NMe2H)2]+ are also discussed, but shown to be higher in energy. Off-cycle adducts between [NMe2H2]+ or [H2B(NMe2H)2]+ and amine-boranes are also discussed that act to modify the kinetics of dehydrocoupling.
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28
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Hood TM, Leforestier B, Gyton MR, Chaplin AB. Synthesis and Structural Dynamics of Five-Coordinate Rh(III) and Ir(III) PNP and PONOP Pincer Complexes. Inorg Chem 2019; 58:7593-7601. [PMID: 31117634 PMCID: PMC6549213 DOI: 10.1021/acs.inorgchem.9b00957] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The synthesis and characterization of a homologous series of five-coordinate rhodium(III) and iridium(III) complexes of PNP (2,6-( tBu2PCH2)2C5H3N) and PONOP (2,6-( tBu2PO)2C5H3N) pincer ligands are described: [M(PNP)(biph)][BArF4] (M = Rh, 1a; Ir, 1b; biph = 2,2'-biphenyl; ArF = 3,5-(CF3)2C6H3) and [M(PONOP)(biph)][BArF4] (M = Rh, 2a; Ir, 2b). These complexes are structurally dynamic in solution, exhibiting pseudorotation of the biph ligand on the 1H NMR time scale (Δ G⧧ ca. 60 kJ mol-1) and, in the case of the flexible PNP complexes, undergoing interconversion between helical and puckered pincer ligand conformations (Δ G⧧ ca. 10 kJ mol-1). Remarkably, the latter is sufficiently facile that it persists in the solid state, leading to temperature-dependent disorder in the associated X-ray crystal structures. Reaction of 1 and 2 with CO occurs for the iridium congeners 1b and 2b, leading to the formation of sterically congested carbonyl derivatives.
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Affiliation(s)
- Thomas M Hood
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
| | - Baptiste Leforestier
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
| | - Matthew R Gyton
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
| | - Adrian B Chaplin
- Department of Chemistry , University of Warwick , Gibbet Hill Road , Coventry CV4 7AL , U.K
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29
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Johnson A, Martínez-Martínez AJ, Macgregor SA, Weller AS. A d 10 Ag(i) amine-borane σ-complex and comparison with a d 8 Rh(i) analogue: structures on the η 1 to η 2:η 2 continuum. Dalton Trans 2019; 48:9776-9781. [PMID: 31012457 DOI: 10.1039/c9dt00971j] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
H3B·NMe3 σ-complexes of d8 [(L1)Rh][BArF4] and d10 [(L1)Ag][BArF4] (where L1 = 2,6-bis-[1-(2,6-diisopropylphenylimino)ethyl]pyridine) have been prepared and structurally characterised. Analysis of the molecular and electronic structures reveal important but subtle differences in the nature of the bonding in these σ-complexes, which differ only by the identity of the metal centre and the d-electron count. With Rh the amine-borane binds in an η2:η2 fashion, whereas at Ag the unsymmetrical {AgH3B·NMe3} unit suggests a structure lying between the η2:η2 and η1 extremes.
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Affiliation(s)
- Alice Johnson
- Chemistry Research Laboratories, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK.
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