Photochemistry of Cp′Mn(CO) 2(NHC) (Cp′ = η 5-C 5H 4Me) species: Synthesis, time-resolved ir spectroscopy, and DFT calculations

Madeeha Batool, Thomas A. Martin, Andrés G. Algarra, Michael W. George, Stuart A. MacGregor, Mary F. Mahon, Michael K. Whittlesey

Research output: Journal PublicationArticlepeer-review

17 Citations (Scopus)

Abstract

UV irradiation of Cp′Mn(CO) 3 (Cp′ = η 5-C 5H 4Me) in the presence of the free N-heterocyclic carbenes IEt 2Me 2, I iPr 2Me 2, IMes, and IPr affords the NHC dicarbonyl complexes Cp′Mn(CO) 2(NHC) (1-4). Time-resolved infrared spectroscopy in alkane solution reveals that 1-4 photodissociate CO to generate Cp′Mn(CO)(NHC) (1-CO, 2-CO, 3-CO, 4-CO), which exhibit solvent-independent second-order rate constants (k CO) for reaction with CO. These observations are consistent with 1-CO to 4-CO being stabilized by intramolecular agostic interactions with the NHCs rather than intermolecular alkane coordination. Density functional theory calculations provide support for this hypothesis and locate a series of agostic structures varying from δ-agostic (1-CO, 2-CO), to ε-agostic (3-CO), to φ-agostic (4-CO). The atoms-in-molecules approach is used to characterize these species, along with the γ-agostic interaction seen in the CpMn(CO)(PPh 3) analogue (5-CO), and shows that these species are distinguished primarily by the magnitude of the electron density at the agostic ring critical point.

Original languageEnglish
Pages (from-to)4971-4979
Number of pages9
JournalOrganometallics
Volume31
Issue number14
DOIs
Publication statusPublished - 23 Jul 2012
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

Fingerprint

Dive into the research topics of 'Photochemistry of Cp′Mn(CO) 2(NHC) (Cp′ = η 5-C 5H 4Me) species: Synthesis, time-resolved ir spectroscopy, and DFT calculations'. Together they form a unique fingerprint.

Cite this