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Cobalt- and rhodium-corrole-triphenylphosphine complexes revisited: the question of a noninnocent corrole

Cobalt- and rhodium-corrole-triphenylphosphine complexes revisited: the question of a noninnocent corrole
Cobalt- and rhodium-corrole-triphenylphosphine complexes revisited: the question of a noninnocent corrole

A reinvestigation of cobalt-corrole-triphenylphosphine complexes has yielded an unexpectedly subtle picture of their electronic structures. UV-vis absorption spectroscopy, skeletal bond length alternations observed in X-ray structures, and broken-symmetry DFT (B3LYP) calculations suggest partial CoII-corrole•2- character for these complexes. The same probes applied to the analogous rhodium corroles evince no evidence of a noninnocent corrole. X-ray absorption spectroscopic studies showed that the Co K rising edge of Co[TPC](PPh3) (TPC = triphenylcorrole) is red-shifted by ∼1.8 eV relative to the bona fide Co(III) complexes Co[TPC](py)2 and Co[TPP](py)Cl (TPP = tetraphenylporphyrin, py = pyridine), consistent with a partial CoII-corrole•2- description for Co[TPC](PPh3). Electrochemical measurements have shown that both the Co and Rh complexes undergo two reversible oxidations and one to two irreversible reductions. In particular, the first reduction of the Rh corroles occurs at significantly more negative potentials than that of the Co corroles, reflecting significantly higher stability of the Rh(III) state relative to Co(III). Together, the results presented herein suggest that cobalt-corrole-triphenylphosphine complexes are significantly noninnocent with moderate CoII-corrole•2- character, underscoring - yet again - the ubiquity of ligand noninnocence among first-row transition metal corroles.

0020-1669
14788-14800
Ganguly, Sumit
0e87078e-c576-4b20-a10d-dafd6288f8b2
Renz, Diemo
4a14efe5-032b-4f93-8f1e-494ff333779b
Giles, Logan J.
13892135-073e-45d1-8913-e55198ae4774
Gagnon, Kevin J.
5535af49-cc12-48b8-b007-28bb1f1b070c
McCormick, Laura J.
f1c2f8cd-adcc-4bbf-9289-0b33a006d2bb
Conradie, Jeanet
814b9b0c-ae44-4f35-b80b-4d27bd575030
Sarangi, Ritimukta
8be920ed-0149-4f14-871b-78eb0bc4c820
Ghosh, Abhik
01a311da-a139-43f0-ae29-0efa0e8788f7
Ganguly, Sumit
0e87078e-c576-4b20-a10d-dafd6288f8b2
Renz, Diemo
4a14efe5-032b-4f93-8f1e-494ff333779b
Giles, Logan J.
13892135-073e-45d1-8913-e55198ae4774
Gagnon, Kevin J.
5535af49-cc12-48b8-b007-28bb1f1b070c
McCormick, Laura J.
f1c2f8cd-adcc-4bbf-9289-0b33a006d2bb
Conradie, Jeanet
814b9b0c-ae44-4f35-b80b-4d27bd575030
Sarangi, Ritimukta
8be920ed-0149-4f14-871b-78eb0bc4c820
Ghosh, Abhik
01a311da-a139-43f0-ae29-0efa0e8788f7

Ganguly, Sumit, Renz, Diemo, Giles, Logan J., Gagnon, Kevin J., McCormick, Laura J., Conradie, Jeanet, Sarangi, Ritimukta and Ghosh, Abhik (2017) Cobalt- and rhodium-corrole-triphenylphosphine complexes revisited: the question of a noninnocent corrole. Inorganic Chemistry, 56 (24), 14788-14800. (doi:10.1021/acs.inorgchem.7b01828).

Record type: Article

Abstract

A reinvestigation of cobalt-corrole-triphenylphosphine complexes has yielded an unexpectedly subtle picture of their electronic structures. UV-vis absorption spectroscopy, skeletal bond length alternations observed in X-ray structures, and broken-symmetry DFT (B3LYP) calculations suggest partial CoII-corrole•2- character for these complexes. The same probes applied to the analogous rhodium corroles evince no evidence of a noninnocent corrole. X-ray absorption spectroscopic studies showed that the Co K rising edge of Co[TPC](PPh3) (TPC = triphenylcorrole) is red-shifted by ∼1.8 eV relative to the bona fide Co(III) complexes Co[TPC](py)2 and Co[TPP](py)Cl (TPP = tetraphenylporphyrin, py = pyridine), consistent with a partial CoII-corrole•2- description for Co[TPC](PPh3). Electrochemical measurements have shown that both the Co and Rh complexes undergo two reversible oxidations and one to two irreversible reductions. In particular, the first reduction of the Rh corroles occurs at significantly more negative potentials than that of the Co corroles, reflecting significantly higher stability of the Rh(III) state relative to Co(III). Together, the results presented herein suggest that cobalt-corrole-triphenylphosphine complexes are significantly noninnocent with moderate CoII-corrole•2- character, underscoring - yet again - the ubiquity of ligand noninnocence among first-row transition metal corroles.

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e-pub ahead of print date: 6 December 2017
Published date: 18 December 2017

Identifiers

Local EPrints ID: 439005
URI: http://eprints.soton.ac.uk/id/eprint/439005
ISSN: 0020-1669
PURE UUID: 4a8ab672-6988-4405-85aa-468dbff9d32b
ORCID for Laura J. McCormick: ORCID iD orcid.org/0000-0002-6634-4717

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Date deposited: 31 Mar 2020 16:31
Last modified: 07 Oct 2020 02:27

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Contributors

Author: Sumit Ganguly
Author: Diemo Renz
Author: Logan J. Giles
Author: Kevin J. Gagnon
Author: Jeanet Conradie
Author: Ritimukta Sarangi
Author: Abhik Ghosh

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