| Title: |
Photochemical Formation and Electronic Structure of an Alkane delta Complex from Time Resolved Optical and X ray Absorption Spectroscopy |
| Authors: |
Jay, R.M.; Coates, M.R.; Zhao, H.; Winghart, M.O.; Han, P.; Wang, R.P.; Harich, J.; Banerjee, A.; Wikmark, H.; Fondell, M.; Nibbering, E.T.J.; Odelius, M.; Huse, N.; Wernet, P. |
| Source: |
Journal of the American Chemical Society 146 2024 , p. 14000 14011 |
| Publication Year: |
2024 |
| Collection: |
Helmholtz Zentrum Berlin (HZB): Publications |
| Subject Terms: |
Optical absorption |
| Description: |
C H bond activation reactions with transition metals typically proceed via the formation of alkane amp; 963; complexes, where an alkane C H amp; 963; bond binds to the metal. Due to the weak nature of metal alkane bonds, amp; 963; complexes are challenging to characterize experimentally. Here, we establish the complete pathways of photochemical formation of the model amp; 963; complex Cr CO 5 alkane from Cr CO 6 in octane solution and characterize the nature of its metal ligand bonding interactions. Using femtosecond optical absorption spectroscopy, we find photoinduced CO dissociation from Cr CO 6 to occur within the 100 fs time resolution of the experiment. Rapid geminate recombination by a fraction of molecules is found to occur with a time constant of 150 fs. The formation of bare Cr CO 5 in its singlet ground state is followed by complexation of an octane molecule from solution with a time constant of 8.2 ps. Picosecond X ray absorption spectroscopy at the Cr L edge and O K edge provides unique information on the electronic structure of the Cr CO 5 alkane amp; 963; complex from both the metal and ligand perspectives. Based on clear experimental observables, we find substantial destabilization of the lowest unoccupied molecular orbital upon coordination of the C H bond to the undercoordinated Cr center in the Cr CO 5 alkane amp; 963; complex, and we define this as a general, orbital based descriptor of the metal alkane bond. Our study demonstrates the value of combining optical and X ray spectroscopic methods as complementary tools to study the stability and reactivity of alkane amp; 963; complexes in their role as the decisive intermediates in C H bond activation reactions |
| Document Type: |
article in journal/newspaper |
| File Description: |
application/pdf |
| Language: |
unknown |
| Relation: |
info:eu-repo/grantAgreement/EU/H2020/788704 |
| Availability: |
https://www.helmholtz-berlin.de/pubbin/oai_publication?VT=1&ID=112918 |
| Rights: |
info:eu-repo/semantics/openAccess |
| Accession Number: |
edsbas.546CD26D |
| Database: |
BASE |