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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/20728
Title: Carbodicarbene Ligand Redox Noninnocence in Highly Oxidized Chromium and Cobalt Complexes
Authors: Chan S.-C.
Ang Z.Z.
Gupta, Puneet
Ganguly R.
Li Y.
Ye S.
England J.
Published in: Inorganic Chemistry
Abstract: Carbodicarbenes (CDCs) possess two lone pairs of electrons on their central carbone C atom (Ccarbone). Coordination to a transition metal via a σ bond leaves one pair of electrons with appropriate symmetry for πdonation to the metal. However, the high energy of the latter also renders the CDC ligand potentially redox-active. Herein, we explore these alternatives in the redox series [Cr(L)2]n+ and [Co(L)2]n+ (n = 2-5), where L is a tridentate ligand comprised of a central CDC and two flanking pyridine donors. To this end, all members of both redox series were synthesized and their electronic structures were investigated by using a combination of 1H NMR, Evans' NMR, IR, UV-vis, and EPR spectroscopies, SQUID magnetometry, X-ray crystallography, and density functional theory studies. Whereas [CoII(L)2]2+ is a straightforward low-spin (S = 1/2) cobalt(II) complex, the corresponding chromium complex was found to feature an electronic structure that is intermediate between the two limiting resonance forms [CrIII(L•-)(L)]2+ and [CrII(L)2]2+. In the case of the tri-, tetra-, and pentacationic complexes, the qualitatively identical electronic structures [MIII(L)2]3+, [MIII(L•+)(L)]4+, and [MIII(L•+)2]5+ were observed for both metals. Thus, the metal ions retain a 3+ oxidation state throughout, and the higher redox states contain oxidized ligands. The majority of the unpaired spin on the cation radical ligands was calculated to be localized in π-symmetry orbitals on the coordinated Ccarbone atoms. Analogous behavior was previously reported for the corresponding iron redox series and, as such, redox noninnocence in oxidized CDC and, more broadly, carbone complexes is likely widely accessible. © 2020 American Chemical Society.
Citation: Inorganic Chemistry, 59(6): 4118-4128
URI: https://doi.org/10.1021/acs.inorgchem.0c00153
http://repository.iitr.ac.in/handle/123456789/20728
Issue Date: 2020
Publisher: American Chemical Society
ISSN: 201669
Author Scopus IDs: 36697633900
57212246724
57215231630
55675224139
57202988209
8346771900
9239275100
Author Affiliations: Chan, S.-C., Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, Singapore, 637371, Singapore
Ang, Z.Z., Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, Singapore, 637371, Singapore
Gupta, P., Max-Plank-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr, D-45470, Germany
Ganguly, R., Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, Singapore, 637371, Singapore
Li, Y., Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, Singapore, 637371, Singapore
Ye, S., Max-Plank-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr, D-45470, Germany, State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China
England, J., Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University (NTU), 21 Nanyang Link, Singapore, 637371, Singapore
Funding Details: J.E. thanks NTU for funding (Grant M4081442). P.G. and S.Y. gratefully acknowledge the financial support of the Max-Planck Society, in particular, the joint work space of MPI-CEC and MPI-KOFO. S.Y. is deeply indebted to Dr. Eckhard Bill for fruitful discussions. Nanyang Technological University, NTU: M4081442; Max-Planck-Gesellschaft, MPG
Corresponding Author: Ye, S.; Max-Plank-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Germany; email: shengfa.ye@dicp.ac.cn
Appears in Collections:Journal Publications [CY]

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