Influence of Copper Oxidation State on the Bonding and Electronic Structure of Cobalt–Copper Complexes
- Univ. of Minnesota, Minneapolis, MN (United States)
- Univ. of Chicago, Argonne, IL (United States)
- Max Planck Inst. für Chemische Energiekonversion, Stiftstraβe (Germany)
Heterobimetallic complexes that pair cobalt and copper were synthesized and characterized by a suite of physical methods, including X-ray diffraction, X-ray anomalous scattering, cyclic voltammetry, magnetometry, electronic absorption spectroscopy, electron paramagnetic resonance, and quantum chemical methods. Both Cu(II) and Cu(I) reagents were independently added to a Co(II) metalloligand to provide (py3tren)CoCuCl (1-Cl) and (py3tren)CoCu(CH3CN) (2-CH3CN), respectively, where py3tren is the triply deprotonated form of N,N,N-tris(2-(2-pyridylamino)ethyl)amine. Complex 2-CH3CN can lose the acetonitrile ligand to generate a coordination polymer consistent with the formula “(py3tren)CoCu” (2). One-electron chemical oxidation of 2-CH3CN with AgOTf generated (py3tren)CoCuOTf (1-OTf). The Cu(II)/Cu(I) redox couple for 1-OTf and 2-CH3CN is reversible at -0.56 and -0.33 V vs Fc+/Fc, respectively. The copper oxidation state impacts the electronic structure of the heterobimetallic core, as well as the nature of the Co–Cu interaction. Quantum chemical calculations showed modest electron delocalization in the (CoCu)+4 state via a Co–Cu σ bond that is weakened by partial population of the Co–Cu σ antibonding orbital. Finally by contrast, no covalent Co–Cu bonding is predicted for the (CoCu)+3 analogue, and the d-electrons are fully localized at individual metals.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Energy Frontier Research Center for Inorganometallic Catalyst Design (ICDC)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0012702; AC02-06CH11357
- OSTI ID:
- 1370855
- Journal Information:
- Inorganic Chemistry, Vol. 54, Issue 23; Related Information: ICDC partners with University of Minnesota(lead); Argonne National Laboratory; Clemson University; Dow Chemical Company; Northwestern University; Pacific Northwest National Laboratory; University of California Davis; University of Washington; ISSN 0020-1669
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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