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Title: Cooperative Activation of CO2 and Epoxide by a Heterobinuclear Al–Fe Complex via Radical Pair Mechanisms

Journal Article · · Journal of the American Chemical Society
DOI:https://doi.org/10.1021/jacs.1c13108· OSTI ID:1903194

Activation of inert molecules like CO2 is often mediated by cooperative chemistry between two reactive sites within a catalytic assembly, the most common form of which is Lewis acid/base bifunctionality observed in both natural metalloenzymes and synthetic systems. Here, we disclose a heterobinuclear complex with an Al–Fe bond that instead activates CO2 and other substrates through cooperative behavior of two radical intermediates. The complex Ldipp(Me)AlFp (2, Ldipp = HC{(CMe)(2,6-iPr2C6H3N)}2, Fp = FeCp(CO)2, Cp = η5-C5H5) was found to insert CO2 and cyclohexene oxide, producing LdippAl(Me)(μ:κ2-O2C)Fp (3) and LdippAl(Me)(μ-OC6H10)Fp (4), respectively. Detailed mechanistic studies indicate unusual pathways in which (i) the Al–Fe bond dissociates homolytically to generate formally AlII and FeI metalloradicals, then (ii) the metalloradicals add to substrate in a pairwise fashion initiated by O-coordination to Al. The accessibility of this unusual mechanism is aided, in part, by the redox noninnocent nature of Ldipp that stabilizes the formally AlII intermediates, instead giving them predominantly AlIII-like physical character. The redox noninnocent nature of the radical intermediates was elucidated through direct observation of LdippAl(Me)(OCPh2) (22), a metalloradical species generated by addition of benzophenone to 2. Complex 22 was characterized by X-band EPR, Q-band EPR, and ENDOR spectroscopies as well as computational modeling. As a result, the “radical pair” pathway represents an unprecedented mechanism for CO2 activation.

Research Organization:
Northwestern Univ., Evanston, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); National Institutes of Health (NIH); National Science Foundation (NSF)
Grant/Contract Number:
SC0019342; SC0021055; R01 GM116820; NSF/CHE-1834750; AC02-06CH11357
OSTI ID:
1903194
Journal Information:
Journal of the American Chemical Society, Vol. 144, Issue 7; ISSN 0002-7863
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English

References (80)

The broadening reach of frustrated Lewis pair chemistry journal December 2016
Metal–Ligand Cooperation by Aromatization–Dearomatization: A New Paradigm in Bond Activation and “Green” Catalysis journal August 2011
Exploiting Metal–Ligand Bifunctional Reactions in the Design of Iron Asymmetric Hydrogenation Catalysts journal April 2015
Bimetallic cooperation across the periodic table journal October 2020
Metal–Metal Bonds in Catalysis journal December 2016
Multimetallic Catalysis Based on Heterometallic Complexes and Clusters journal November 2014
Carbon dioxide complexes: Bonding modes and synthetic methods journal March 2017
Opportunities and Challenges for Catalysis in Carbon Dioxide Utilization journal July 2019
Frontiers, Opportunities, and Challenges in Biochemical and Chemical Catalysis of CO 2 Fixation journal June 2013
The Organometallic Chemistry of Carbon Dioxide journal January 1996
Carbon dioxide fixation: bifunctional complexes containing acidic and basic sites working as reversible carriers journal September 1982
Bifunctional activation of carbon dioxide. Synthesis and structure of a reversible carbon dioxide carrier journal November 1978
Reaction of Carbon Dioxide and Heterocumulenes with an Unsymmetrical Metal-Metal Bond. Direct Addition of Carbon Dioxide across a Zirconium-Iridium Bond and Stoichiometric Reduction of Carbon Dioxide to Formate journal November 1995
Activation of CO 2 by a Heterobimetallic Zr/Co Complex journal September 2011
Reversible Metal-Free Carbon Dioxide Binding by Frustrated Lewis Pairs journal August 2009
Role of Ligand-Bound CO 2 in the Hydrogenation of CO 2 to Formate with a (PNP)Mn Catalyst journal June 2021
Strongly Polarized Iridium δ− –Aluminum δ+ Pairs: Unconventional Reactivity Patterns Including CO 2 Cooperative Reductive Cleavage journal March 2021
Crystal Structure of a Carbon Monoxide Dehydrogenase Reveals a [Ni-4Fe-5S] Cluster journal August 2001
Cooperative Strategies for Catalytic Hydrogenation of Unsaturated Hydrocarbons journal August 2017
Mechanisms for CO Production from CO 2 Using Reduced Rhenium Tricarbonyl Catalysts journal March 2012
A Radical Mechanism for Frustrated Lewis Pair Reactivity journal August 2017
Frustrated Radical Pairs: Insights from EPR Spectroscopy journal November 2020
H2 and carbon-heteroatom bond activation mediated by polarized heterobimetallic complexes journal April 2021
Selective Reduction of CO 2 to a Formate Equivalent with Heterobimetallic Gold- - -Copper Hydride Complexes journal October 2017
Selectivity Effects in Bimetallic Catalysis journal February 2016
Catalyst Control of Selectivity in CO 2 Reduction Using a Tunable Heterobimetallic Effect journal August 2015
Paramagnetic Metal–Metal Bonded Heterometallic Complexes journal February 2020
Main-group elements as transition metals journal January 2010
Unexpected B/Al Transelementation within a Rh Pincer Complex journal December 2020
Rhodium Complexes Bearing PAlP Pincer Ligands journal May 2018
Addition of aluminium, zinc and magnesium hydrides to rhodium( iii ) journal January 2015
Ni complexes of an alane/tris(phosphine) ligand built around a strongly Lewis acidic tris( N -pyrrolyl)aluminum journal January 2020
Synthesis and X-ray Crystal Structure of (tmp) 2 Al−Fe(cp)(CO) 2 :  An Alanyl-Containing Iron Complex with a Tricoordinated Aluminum Atom journal April 1997
Molecular Structure of [CpFe(CO) 2 ] 2 AlAr (Ar = 2-[(Dimethylamino)methyl]phenyl):  An Alanediyl Complex with Two Fe−Al Bonds journal January 1996
Molecular Complexes Featuring Unsupported Dispersion-Enhanced Aluminum–Copper and Gallium–Copper Bonds journal November 2020
Ambiphilic Al−Cu Bonding journal May 2021
Metal–Alane Adducts with Zero-Valent Nickel, Cobalt, and Iron journal December 2011
1 st row transition metal aluminylene complexes: preparation, properties and bonding analysis journal January 2021
A nucleophilic gold complex journal January 2019
Reactivity of a Gold-Aluminyl Complex with Carbon Dioxide: A Nucleophilic Gold? journal September 2021
Coinage metal aluminyl complexes: probing regiochemistry and mechanism in the insertion and reduction of carbon dioxide journal January 2021
Probing the Extremes of Covalency in M−Al bonds: Lithium and Zinc Aluminyl Compounds journal September 2021
Transition-Metal-Substituted Alanes: Synthesis and Spectroscopic Studies and the Structure of (.eta.5-C5H5)(CO)2Fe-Al[(CH2)3NMe2](iBu) journal November 1994
Synthesis and characterisation of complexes of Group 13 metal amidinate heterocycles with the CpFe(CO)2 fragment journal January 2006
Salt metathesis for the synthesis of M–Al and M–H–Al bonds journal January 2013
Dibromometallyl-iron complexes generated by the recombination of an alumanyl-iron complex with EBr 3 (E = Al, Ga) journal December 2018
Synthesis and Structure of an Iron-Bromoalumanyl Complex with a Tri-Coordinated Aluminum Center journal October 2016
[(η5-C5Me5)AlFe(CO)4]—Synthesis, Structure, and Bonding journal February 1997
A Powerful Aluminum Catalyst for the Synthesis of Highly Functional Organic Carbonates journal January 2013
Carbon dioxide insertion into the iron-zirconium and ruthenium-zirconium bonds of the heterobimetallic complexes Cp(CO)2MZr(Cl)Cp2: direct production of the .mu.-.eta.1(C):.eta.2(O,O')-CO2 compounds Cp(CO)2MCO2Zr(Cl)Cp2 journal January 1994
Carbonylative, Catalytic Deoxygenation of 2,3-Disubstituted Epoxides with Inversion of Stereochemistry: An Alternative Alkene Isomerization Method journal April 2020
Insertion of XCY heteroallenes into unsupported Zr–M bonds (M = Fe, Ru) journal January 1996
Bromopropyldicarbonyl(η 5 -pentamethylcyclopentadienyl)iron(II) journal April 2004
Migratory Aptitude of the Zr-C Functionalities Bonded to a Macrocyclic Structure: Thermally- and Solvent-Assisted Intra- and Intermolecular Migrations in Dialkyl(dibenzotetramethyltetraazaannulene)zirconium(IV) journal May 1995
On the non-innocence of “Nacnacs”: ligand-based reactivity in β-diketiminate supported coordination compounds journal January 2016
Natural hybrid orbitals journal September 1980
Natural bond orbital analysis of near‐Hartree–Fock water dimer journal March 1983
A quantum theory of molecular structure and its applications journal July 1991
Properties of atoms in molecules: Atomic polarizabilities journal November 1990
Heterobimetallic Complexes with Polar, Unsupported Cu–Fe and Zn–Fe Bonds Stabilized by N-Heterocyclic Carbenes journal July 2013
Application of the pople-santry-segal CNDO method to the cyclopropylcarbinyl and cyclobutyl cation and to bicyclobutane journal January 1968
Symmetry decomposition of quantum chemical bond orders journal December 2008
Carbon Dioxide Complexation:  Infrared Spectroscopy of Iron and Ruthenium η 5 -Cyclopentadienyl Carbonyl Metallocarboxylates journal January 1997
A Linear, O-Coordinated  1-CO2 Bound to Uranium journal September 2004
CO2 reduction by Fe(i): solvent control of C–O cleavage versus C–C coupling journal January 2013
Reversible Reductive Elimination in Aluminum(II) Dihydrides journal November 2020
Stoichiometric C═O Bond Oxidative Addition of Benzophenone by a Discrete Radical Intermediate To Form a Cobalt(I) Carbene journal April 2013
A CW-EPR, ENDOR and special TRIPLE resonance study of a novel magnesium ketyl radical: EPR and ENDOR of Mg-ketyl radical journal January 2011
Tumbling of an adsorbed nitroxide using rapid adiabatic passage journal April 1976
Rapid adiabatic passage EPR of ferricytochrome : Signal enhancement and determination of the spin-lattice relaxation time journal October 1973
The Role of Microwave Frequency in EPR Spectroscopy of Copper Complexes journal June 1982
A Stable Neutral Radical in the Coordination Sphere of Aluminum journal December 2016
Cyclic (Alkyl)(Amino)Carbene-Stabilized Aluminum and Gallium Radicals Based on Amidinate Scaffolds journal August 2020
Metal Bonding with 3d and 6d Orbitals: An EPR and ENDOR Spectroscopic Investigation of Ti 3+ –Al and Th 3+ –Al Heterobimetallic Complexes journal June 2019
Atomic parameters for paramagnetic resonance data journal June 1978
Toward reliable density functional methods without adjustable parameters: The PBE0 model journal April 1999
Effect of the damping function in dispersion corrected density functional theory journal March 2011
Balanced basis sets of split valence, triple zeta valence and quadruple zeta valence quality for H to Rn: Design and assessment of accuracy journal January 2005
Universal Solvation Model Based on Solute Electron Density and on a Continuum Model of the Solvent Defined by the Bulk Dielectric Constant and Atomic Surface Tensions
  • Marenich, Aleksandr V.; Cramer, Christopher J.; Truhlar, Donald G.
  • The Journal of Physical Chemistry B, Vol. 113, Issue 18, p. 6378-6396 https://doi.org/10.1021/jp810292n
journal May 2009
Multiwfn: A multifunctional wavefunction analyzer journal December 2011