Abstract
Cobalt-carbon bond cleavage is crucial to most natural and synthetic applications of the cobalamin class of compounds, and here we present the first direct electronic and geometric structural characteristics of intermediates formed following photoexcitation of methylcobalamin (MeCbl) using time-resolved X-ray absorption spectroscopy (XAS). We catch transients corresponding to two intermediates, in the hundreds of picoseconds and a few microseconds. Highlights of the picosecond intermediate, which is reduced in comparison to the ground state, are elongation of the upper axial Co-C bond and relaxation of the corrin ring. This is not so with the recombining photocleaved products captured at a few microseconds, where the Co-C bond almost (yet not entirely) reverts to its ground state configuration and a substantially elongated lower axial Co-NIm bond is observed. The reduced cobalt site here confirms formation of methyl radical as the photoproduct.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1542-1546 |
| Number of pages | 5 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 9 |
| Issue number | 7 |
| DOIs | |
| State | Published - Apr 5 2018 |
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ASJC Scopus subject areas
- Materials Science(all)
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Direct Structural and Chemical Characterization of the Photolytic Intermediates of Methylcobalamin Using Time-Resolved X-ray Absorption Spectroscopy. / Subramanian, Ganesh; Zhang, Xiaoyi; Kodis, Gerdenis; Kong, Qingyu; Liu, Cunming; Chizmeshya, Andrew; Weierstall, Uwe; Spence, John.
In: Journal of Physical Chemistry Letters, Vol. 9, No. 7, 05.04.2018, p. 1542-1546.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Direct Structural and Chemical Characterization of the Photolytic Intermediates of Methylcobalamin Using Time-Resolved X-ray Absorption Spectroscopy
AU - Subramanian, Ganesh
AU - Zhang, Xiaoyi
AU - Kodis, Gerdenis
AU - Kong, Qingyu
AU - Liu, Cunming
AU - Chizmeshya, Andrew
AU - Weierstall, Uwe
AU - Spence, John
PY - 2018/4/5
Y1 - 2018/4/5
N2 - Cobalt-carbon bond cleavage is crucial to most natural and synthetic applications of the cobalamin class of compounds, and here we present the first direct electronic and geometric structural characteristics of intermediates formed following photoexcitation of methylcobalamin (MeCbl) using time-resolved X-ray absorption spectroscopy (XAS). We catch transients corresponding to two intermediates, in the hundreds of picoseconds and a few microseconds. Highlights of the picosecond intermediate, which is reduced in comparison to the ground state, are elongation of the upper axial Co-C bond and relaxation of the corrin ring. This is not so with the recombining photocleaved products captured at a few microseconds, where the Co-C bond almost (yet not entirely) reverts to its ground state configuration and a substantially elongated lower axial Co-NIm bond is observed. The reduced cobalt site here confirms formation of methyl radical as the photoproduct.
AB - Cobalt-carbon bond cleavage is crucial to most natural and synthetic applications of the cobalamin class of compounds, and here we present the first direct electronic and geometric structural characteristics of intermediates formed following photoexcitation of methylcobalamin (MeCbl) using time-resolved X-ray absorption spectroscopy (XAS). We catch transients corresponding to two intermediates, in the hundreds of picoseconds and a few microseconds. Highlights of the picosecond intermediate, which is reduced in comparison to the ground state, are elongation of the upper axial Co-C bond and relaxation of the corrin ring. This is not so with the recombining photocleaved products captured at a few microseconds, where the Co-C bond almost (yet not entirely) reverts to its ground state configuration and a substantially elongated lower axial Co-NIm bond is observed. The reduced cobalt site here confirms formation of methyl radical as the photoproduct.
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U2 - 10.1021/acs.jpclett.8b00083
DO - 10.1021/acs.jpclett.8b00083
M3 - Article
VL - 9
SP - 1542
EP - 1546
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 7
ER -