Very Large Infrared Two-Photon Absorption Cross Section of Asymmetric Zinc Porphyrin Aggregates:  Role of Intermolecular Interaction and Donor−Acceptor Strengths

2006 ◽  
Vol 110 (44) ◽  
pp. 12342-12347 ◽  
Author(s):  
Paresh Chandra Ray ◽  
Zuhail Sainudeen
Keyword(s):  
Intermolecular Interaction ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Zinc Porphyrin ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Donor Acceptor

Syntheses and properties of acetylene-linked bis- and trisporphyrins toward two-photon photodynamic therapy

2007 ◽  
Vol 11 (06) ◽  
pp. 406-417 ◽  
Author(s):  
Yusuke Inaba ◽  
Kazuya Ogawa ◽  
Yoshiaki Kobuke
Keyword(s):  
Photodynamic Therapy ◽  
Cross Section ◽  
Sodium Salt ◽  
Absorption Cross Section ◽  
Water Soluble ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Two Photon Absorption ◽  
Photon Irradiation ◽  
Two Photon

Acetylene-bridged bisporphyrins and trisporphyrins having branched bulky bis(carboxylethyl)methyl meso-substituents were synthesized. These compounds showed large effective two-photon absorption cross-section values at 890 nm measured by using a nanosecond Z-scan method. Sodium salt of hydrolyzed trisporphyrins showed broad and red-shifted Q-bands over 900 nm. Two-photon absorption cross-section values of water-soluble dimers in water were similar to, or slightly larger than, those of ester forms evaluated in toluene. Furthermore, the generation of singlet oxygen upon one-photon irradiation for dimers in water was confirmed.

scholarly journals Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

2019 ◽  
Vol 15 ◽  
pp. 2438-2446 ◽  
Author(s):  
Alessandro Iagatti ◽  
Baihao Shao ◽  
Alberto Credi ◽  
Barbara Ventura ◽  
Ivan Aprahamian ◽  
...  
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Transient Absorption ◽  
Solvent Polarity ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Time Resolved ◽  
Two Photon Absorption ◽  
Two Photon

In this work we apply a combination of steady state and time resolved luminescence and absorption spectroscopies to investigate the excited-state dynamics of a recently developed molecular photoswitch, belonging to the hydrazone family. The outstanding properties of this molecule, involving fluorescence toggling, bistability, high isomerization quantum yield and non-negligible two-photon absorption cross section, make it very promising for numerous applications. Here we show that the light induced Z/E isomerization occurs on a fast <1 ps timescale in both toluene and acetonitrile, while the excited state lifetime of the Z-form depends on solvent polarity, suggesting a partial charge transfer nature of its low lying excited state. Time-resolved luminescence measurements evidence the presence of a main emission component in the 500–520 nm spectral range, attributed to the Z-isomer, and a very short living blue-shifted emission, attributed to the E-isomer. Finally, transient absorption measurements performed upon far-red excitation are employed as an alternative method to determine the two-photon absorption cross-section of the molecule.

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