View : 52 Download: 0

The Oxo-Wall Remains Intact: A Tetrahedrally Distorted Co(IV)-Oxo Complex

Title
The Oxo-Wall Remains Intact: A Tetrahedrally Distorted Co(IV)-Oxo Complex
Authors
Yang, JindouDong, Hai T.Seo, Mi SookLarson, Virginia A.Lee, Yong-MinShearer, JasonLehnert, NicolaiNam, Wonwoo
Ewha Authors
남원우이용민서미숙
SCOPUS Author ID
남원우scopus; 이용민scopusscopusscopus; 서미숙scopus
Issue Date
2021
Journal Title
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
ISSN
0002-7863JCR Link

1520-5126JCR Link
Citation
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY vol. 143, no. 41, pp. 16943 - 16959
Publisher
AMER CHEMICAL SOC
Indexed
SCIE; SCOPUS WOS
Document Type
Article
Abstract
In this paper, we report the preparation, spectro-scopic and theoretical characterization, and reactivity studies of a Co(IV)-oxo complex bearing an N4-macrocyclic coligand, 12-TBC (12-TBC = 1,4,7,10-tetrabenzyl-1,4,7,10-tetraazacyclododecane). On the basis of the ligand and the structure of the Co(II) precursor, [Co-II(12-TBC)(CF3SO3)(2)], one would assume that this species corresponds to a tetragonal Co(IV)-oxo complex, but the spectroscopic data do not support this notion. Co K-edge XAS data show that the treatment of the Co( II) precursor with iodosylbenzene (PhIO) as an oxidant at -40 degrees C in the presence of a proton source leads to a distinct shift in the Co K-edge, in agreement with the formation of a Co(IV) intermediate. The presence of the oxo group is further demonstrated by resonance Raman (rRaman) spectroscopy. Interestingly, the EPR data of this complex show a high degree of rhombicity, indicating structural distortion. This is further supported by the EXAFS data. Using DFT calculations, a structural model is developed for this complex with a ligand-protonated structure that features a Co = O center dot center dot center dot HN hydrogen bond and a four-coordinate Co center in a seesaw-shaped coordination geometry. Magnetic circular dichroism (MCD) spectroscopy further supports this finding. The hydrogen bond leads to an interesting polarization of the Co-oxo pi-bonds, where one O(p) lone-pair is stabilized and leads to a regular Co(d) interaction, whereas the other pi-bond shows an inverted ligand field. The reactivity of this complex in hydrogen atom and oxygen atom transfer reactions is discussed as well.
DOI
10.1021/jacs.1c04919
Appears in Collections:
자연과학대학 > 화학·나노과학전공 > Journal papers
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE