Agostic Isomers: different colors and structures

Agostomers orbitals

Researchers from PNNL have, for the first time, isolated and characterized two agostic isomers (‘agostomers’). Isomers of a cationic Mo piano stool complex, important intermediates in catalytic hydrogenation, have been separated by crystallization and can interconvert upon dissolution. The γ-agostomer of [CpMo(CO)2(PiPr3)]+ has a blue color, while the β-agostomer is orange. ADF calculations confirm that the two agostomers are very close in energy and the calculated VIS/NIR spectra are in good agreement with the experimental data. While the frontier orbitals of the two isomers are very similar, the LUMO of the β-agostomer is higher in energy by 0.64 eV compared to the γ-agostomer, resulting in the observed higher absorption energy.


Agostomers orbitals DFT

LUMO and HOMO of β-agostomer (left) and γ-agostomer (right) of [CpMo(CO)2(PiPr3)]+. The β-agostomer absorbs shorter wavelength of light in the VIS absorption, resulting in orange-colored crystals for the β-agostomer and blue-colored crystals for the γ-agostomer.

Go to overview

Stay up to date!

Subscribe to our newsletter (5 times a year) to stay up to date about news, job openings, functionality and events such as webinars and workshops!

No sales. No spam. Occasional notifications. Unsubscribe anytime.