Longer-Wavelength-Absorbing, Extended Chalcogenorhodamine Dyes
Sponsor
This research was supported in part by the National Science Foundation (Grant CHE-1151379) and by a contract from the Wake Forest Medical Center to M.R.D. and M.W.K.
Published In
Organometallics
Document Type
Citation
Publication Date
5-19-2016
Abstract
Extended rhodamines were prepared by inserting an additional fused benzene ring into the rhodamine xanthylium core. The synthesis of “bent” dyes 4-E (E = S, Se, Te) began with regioselective lithiation of the 1-position of N,N-diisopropyl 6-dimethylamino-2-naphthamide (11b) with n-BuLi/TMEDA (≥25:1 1- vs 3-lithiation) followed by addition of a dichalcogenide electrophile. The synthesis of “linear” dyes 5-E (E = S, Se, Te) began with regioselective lithiation of the 3-position of N,N-diethyl 6-dimethylamino-2-naphthamide (11a) with lithium tetramethylpiperidide (≥50:1 3- vs 1-lithiation) followed by addition of a dichalcogenide electrophile. Dyes 4-E and 5-E have absorption maxima in the 633–700 nm range. Dyes 4-E generate singlet oxygen upon irradiation while dyes 4-S and 5-S are highly fluorescent, with quantum yields for fluorescence of 0.47 and 0.18, respectively. DFT calculations were performed on the 4-E and 5-E chromophores. For the dyes 4-E, the lowest energy excitation is due solely to the HOMO–LUMO transition. For dyes 5-E, the lowest energy excitation is a combination of two excitations, both having contributions from the HOMO to LUMO and HOMO-1 to LUMO.
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DOI
10.1021/acs.organomet.6b00255
Persistent Identifier
http://archives.pdx.edu/ds/psu/18867
Citation Details
Kryman, M. W., McCormick, T. M., & Detty, M. R. (2016). Longer-Wavelength-Absorbing, Extended Chalcogenorhodamine Dyes. Organometallics, 35(11), 1944-1955.