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Li S, Schröder M, Prudlik A, Shi X, Spannenberg A, Rabeah J, Francke R, Corzilius B, Reiß F, Beweries T. A General Concept for the Electronic and Steric Modification of 1-Metallacyclobuta-2,3-dienes: A Case Study of Group 4 Metallocene Complexes. Chemistry 2024; 30:e202400708. [PMID: 38529695 DOI: 10.1002/chem.202400708] [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: 02/21/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 03/27/2024]
Abstract
The synthesis of group 4 metal 1-metallacyclobuta-2,3-dienes as organometallic analogues of elusive 1,2-cyclobutadiene has so far been limited to SiMe3 substituted examples. We present the synthesis of two Ph substituted dilithiated ligand precursors for the preparation of four new 1-metallacyclobuta-2,3-dienes [rac-(ebthi)M] (M=Ti, Zr; ebthi=1,2-ethylene-1,10-bis(η5-tetrahydroindenyl)). The organolithium compounds [Li2(RC3Ph)] (1 b: R=Ph, 1 c: R=SiMe3) as well as the metallacycles of the general formula [rac-(ebthi)M(R1C3R2)] (2 b: M=Ti, R1=R2=Ph, 2 c: M=Ti, R1=Ph, R2=SiMe3; 3 b: M=Zr, R1=R2=Ph; 3 c: M=Zr, R1=Ph, R2=SiMe3) were fully characterised. Single crystal X-ray diffraction and quantum chemical bond analysis of the Ti and Zr complexes reveal ligand influence on the biradicaloid character of the titanocene complexes. X-band EPR spectroscopy of structurally similar Ti complexes [rac-(ebthi)Ti(Me3SiC3SiMe3)] (2 a), 2 b, and 2 c was carried out to evaluate the accessibility of an EPR active triplet state. Cyclic voltammetry shows that introduction of Ph groups renders the complexes easier to reduce. 13C CPMAS NMR analysis provides insights into the cause of the low field shift of the resonances of metal-bonded carbon atoms and provides evidence of the absence of the β-C-Ti interaction.
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Affiliation(s)
- Sihan Li
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Mirjam Schröder
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
- University of Rostock, Institute of Chemistry, 18059, Rostock, Germany
- University of Rostock, Department LL&M, 18059, Rostock, Germany
| | - Adrian Prudlik
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
- University of Rostock, Institute of Chemistry, 18059, Rostock, Germany
| | - Xinzhe Shi
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, P. R. China
| | - Anke Spannenberg
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Jabor Rabeah
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Robert Francke
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Björn Corzilius
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
- University of Rostock, Institute of Chemistry, 18059, Rostock, Germany
- University of Rostock, Department LL&M, 18059, Rostock, Germany
| | - Fabian Reiß
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
| | - Torsten Beweries
- Leibniz Institute for Catalysis, Albert-Einstein-Str. 29a, 18059, Rostock, Germany
- University of Rostock, Department LL&M, 18059, Rostock, Germany
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Russell JB, Jafari MG, Kim JH, Pudasaini B, Ozarowski A, Telser J, Baik MH, Mindiola DJ. Ynamide and Azaalleneyl. Acid-Base Promoted Chelotropic and Spin-State Rearrangements in a Versatile Heterocumulene [(Ad)NCC( tBu)] . Angew Chem Int Ed Engl 2024; 63:e202401433. [PMID: 38433099 DOI: 10.1002/anie.202401433] [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: 01/20/2024] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/05/2024]
Abstract
We introduce the heterocumulene ligand [(Ad)NCC(tBu)]- (Ad=1-adamantyl (C10H15), tBu=tert-butyl, (C4H9)), which can adopt two forms, the azaalleneyl and ynamide. This ligand platform can undergo a reversible chelotropic shift using Brønsted acid-base chemistry, which promotes an unprecedented spin-state change of the [VIII] ion. These unique scaffolds are prepared via addition of 1-adamantyl isonitrile (C≡NAd) across the alkylidyne in complexes [(BDI)V≡CtBu(OTf)] (A) (BDI-=ArNC(CH3)CHC(CH3)NAr), Ar=2,6-iPr2C6H3) and [(dBDI)V≡CtBu(OEt2)] (B) (dBDI2-=ArNC(CH3)CHC(CH2)NAr). Complex A reacts with C≡NAd, to generate the high-spin [VIII] complex with a κ1-N-ynamide ligand, [(BDI)V{κ1-N-(Ad)NCC(tBu)}(OTf)] (1). Conversely, B reacts with C≡NAd to generate a low-spin [VIII] diamagnetic complex having a chelated κ2-C,N-azaalleneyl ligand, [(dBDI)V{κ2-N,C-(Ad)NCC(tBu)}] (2). Theoretical studies have been applied to better understand the mechanism of formation of 2 and the electronic reconfiguration upon structural rearrangement by the alteration of ligand denticity between 1 and 2.
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Affiliation(s)
- John B Russell
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, United States
| | - Mehrafshan G Jafari
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, United States
| | - Jun-Hyeong Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) & Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| | - Bimal Pudasaini
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) & Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, 32310, United States
| | - Joshua Telser
- Department of Biological, Physical and Health Sciences, Roosevelt University, Chicago, Illinois, 60605, United States
| | - Mu-Hyun Baik
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) & Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, Republic of Korea
| | - Daniel J Mindiola
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, United States
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Jafari MG, Russell JB, Lee H, Pudasaini B, Pal D, Miao Z, Gau MR, Carroll PJ, Sumerlin BS, Veige AS, Baik MH, Mindiola DJ. Vanadium Alkylidyne Initiated Cyclic Polymer Synthesis: The Importance of a Deprotiovanadacyclobutadiene Moiety. J Am Chem Soc 2024; 146:2997-3009. [PMID: 38272018 DOI: 10.1021/jacs.3c08149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Reported is the catalytic cyclic polymer synthesis by a 3d transition metal complex: a V(V) alkylidyne, [(dBDI)V≡CtBu(OEt2)] (1-OEt2), supported by the deprotonated β-diketiminate dBDI2- (dBDI2- = ArNC(CH3)CHC(CH2)NAr, Ar = 2,6-iPr2C6H3). Complex 1-OEt2 is a precatalyst for the polymerization of phenylacetylene (PhCCH) to give cyclic poly(phenylacetylene) (c-PPA), whereas its precursor, complex [(BDI)V≡CtBu(OTf)] (2-OTf; BDI- = [ArNC(CH3)]2CH, Ar = 2,6-iPr2C6H3, OTf = OSO2CF3), and the zwitterion [((C6F5)3B-dBDI)V≡CtBu(OEt2)] (3-OEt2) exhibit low catalytic activity despite having a neopentylidyne ligand. Cyclic polymer topologies were verified by size-exclusion chromatography (SEC) and intrinsic viscosity studies. A component of the mechanism of the cyclic polymerization reaction was probed by isolation and full characterization of 4- and 6-membered metallacycles as model intermediates. Metallacyclobutadiene (MCBD) and deprotiometallacyclobutadiene (dMCBD) complexes (dBDI)V[C(tBu)C(H)C(tBu)] (4-tBu) and (BDI)V[C(tBu)CC(Mes)] (5-Mes), respectively, were synthesized upon reaction with bulkier alkynes, tBu- (tBuCCH) and Mes-acetylene (MesCCH), with 1-OEt2. Furthermore, the reaction of the conjugate acid of 1-OEt2, [(BDI)V≡CtBu(OTf)] (2-OTf), with the conjugated base of phenylacetylene, lithium phenylacetylide (LiCCPh), yields the doubly deprotio-metallacycle complex, [Li(THF)4]{(BDI)V[C(Ph)CC(tBu)CC(Ph)]} (6). Protonation of the doubly deprotio-metallacycle complex 6 yields 6-H+, a catalytically active species toward the polymerization of PhCCH, for which the polymers were also confirmed to be cyclic by SEC studies. Computational mechanistic studies complement the experimental observations and provide insight into the mechanism of cyclic polymer growth. The noninnocence of the supporting dBDI2- ligand and its role in proton shuttling to generate deprotiometallacyclobutadiene (dMCBD) complexes that proposedly culminate in the formation of catalytically active V(III) species are also discussed. This work demonstrates how a dMCBD moiety can react with terminal alkynes to form cyclic polyalkynes.
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Affiliation(s)
- Mehrafshan G Jafari
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - John B Russell
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Hanna Lee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Bimal Pudasaini
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Digvijayee Pal
- Department of Chemistry, Center for Catalysis, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Zhihui Miao
- Department of Chemistry, Center for Catalysis, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Michael R Gau
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Patrick J Carroll
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Brent S Sumerlin
- Department of Chemistry, Center for Catalysis, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Adam S Veige
- Department of Chemistry, Center for Catalysis, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Mu-Hyun Baik
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Daniel J Mindiola
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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