title: Mo2 paddlewheel complexes functionalized with a single MLCT, S1 infrared-active carboxylate reporter ligand: preparation and studies of ground and photoexcited states.
abstract: From the reactions between Mo2(DAniF)3pivalate (DAniF = N,N'-di(p-anisyl)formamidinate) and the carboxylic acids LH, the title compounds Mo2(DAniF)3L have been prepared and characterized: compounds I (L = O2CC≡CPh), II (L = O2CC4H2SC≡CH), and III (L = O2CC6H4-p-CN). The new compounds have been characterized in their ground states by spectroscopy ((1)H NMR, ultraviolet-visible absorption, near-infrared absorption, and steady state emission), cyclic voltammetry, and density functional theory calculations. The compounds show strong metal Mo2 to ligand L δ-π* transitions in their visible spectra. The nature of the S1 (1)MLCT and T1 states has been probed by time-resolved (femtosecond and nanosecond) transient absorption and infrared spectroscopy. The observed shifts of the C≡C and C≡N vibrational modes are found to be consistent with the negative charge being localized on the single L in the S1 states, while the T1 states are (3)Mo2 δδ*. The present results are compared to earlier studies of the photoexcited states of trans-Mo2(2,4,6-triisopropylbenzoate)2L2 compounds that have been assigned as either localized or delocalized.
authors.affiliation: Department of Chemistry and Biochemistry, The Ohio State University , 100 W. 18th Avenue, Columbus, Ohio 43210, United States.
authors.forename: Samantha E
authors.initials: SE
authors.lastname: Brown-Xu
authors.forename: Malcolm H
authors.initials: MH
authors.lastname: Chisholm
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Durr
authors.forename: Sharlene A
authors.initials: SA
authors.lastname: Lewis
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Spilker
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Young