%0 Journal Article %A Kryman, Mark W. %A McCormick, Theresa M. %A Detty, Michael R. %D 2016 %T Longer-Wavelength-Absorbing, Extended Chalcogenorhodamine Dyes %U https://acs.figshare.com/articles/journal_contribution/Longer-Wavelength-Absorbing_Extended_Chalcogenorhodamine_Dyes/3386104 %R 10.1021/acs.organomet.6b00255.s001 %2 https://ndownloader.figshare.com/files/5289997 %K regioselective lithiation %K dye %K energy excitation %K LUMO %K dimethylamino %K HOMO %K DFT %K Se %K rhodamine xanthylium core %K synthesis %K vs %K Te %K dichalcogenide electrophile %K Extended Chalcogenorhodamine Dyes Extended rhodamines %X 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. %I ACS Publications