title: Single- and two-photon properties of a dye-derivatized Roussin's red salt ester (Fe2(mu-RS)2(NO)4) with a large TPA cross section.
abstract: The synthesis, characterization, photochemistry, and two-photon photophysical properties of a new dye-derivatized iron sulfur nitrosyl cluster Fe2(mu-RS)2(NO)4 (AFX-RSE, RS = 2-thioethyl ester of N-phenyl-N-(3-(2-ethoxy)phenyl)-7-(benzothiazol-2-yl)-9,9-diethyl-fluoren-2-yl-amine) were investigated. Under continuous photolysis, AFX-RSE decomposes with modest quantum yields (Phi(diss) = (4.9 +/- 0.9) x 10(-3) at lambda(irr) = 436 nm) as measured from the loss of the nitrosyl bands in the IR absorbance spectrum. Nitric oxide (NO) was qualitatively demonstrated to be photochemically produced via single-photon excitation through the use of an NO-specific electrode. Steady-state luminescence measurements have shown that AFX-RSE fluorescence is about 88% quenched relative to the model compound AF-tosyl. This is attributed to a relatively efficient energy transfer from the excited states of the antenna chromophores to the dinuclear metal center, with the subsequent production of NO. In addition, the two-photon absorption (TPA) cross sections (delta) were measured for the AF-chromophores via the two-photon excitation (TPE) photoluminescence technique using a femtosecond excitation source. The TPA cross section of AFX-RSE was found with this technique to be delta = 246 +/- 8 GM (1 GM = 10(-50) cm4 s photon(-1) molecule(-1)).
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, USA.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Wecksler
authors.forename: Alexander
authors.initials: A
authors.lastname: Mikhailovsky
authors.forename: Dmitry
authors.initials: D
authors.lastname: Korystov
authors.forename: Fabian
authors.initials: F
authors.lastname: Buller
authors.forename: Ramamurthi
authors.initials: R
authors.lastname: Kannan
authors.forename: Loon-Seng
authors.initials: LS
authors.lastname: Tan
authors.forename: Peter C
authors.initials: PC
authors.lastname: Ford
mesh_terms: D004952:Esters; D005453:Fluorescence; D058085:Iron Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D009569:Nitric Oxide / Q000737:chemistry*; D010777:Photochemistry; D017785:Photons
chemical_list: D004952:Esters; D058085:Iron Compounds; D009569:Nitric Oxide; C106536:Roussin's red salt