Tatu Kumpulainen

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The excited-state proton transfer and subsequent intramolecular ion pair formation of a cupreidine-derived Cinchona organocatalyst (BnCPD) were studied in THF-water mixtures using picosecond time-resolved fluorescence together with global analysis. Full spectral and kinetic characterization of all the fluorescent species allowed us to monitor the 3-step(More)
Synthesis and characterization of three phthalocyanine-fullerene (Pc-C(60)) dyads, corresponding monoisomeric phthalocyanines (Pc), and building blocks, phthalonitriles, are described. Six novel bisaryl phthalonitriles were prepared by the Suzuki-Miyaura coupling reaction from trifluoromethanesulfonic acid 2,3-dicyanophenyl ester and various oxaborolanes.(More)
Efficient electronic energy transfer (EET) in the newly synthesized dyads comprised of zinc porphyrin covalently linked to one, two or four numbers of boron dipyrrin (BDP) entities is investigated. Both steady-state and time-resolved emission as well as transient absorption studies revealed occurrence of efficient singlet-singlet energy transfer from BDP to(More)
Ultrafast photochemical reactions in liquids occur on similar or shorter time scales compared to the equilibration of the optically populated excited state. This equilibration involves the relaxation of intramolecular and/or solvent modes. As a consequence, the reaction dynamics are no longer exponential, cannot be quantified by rate constants, and may(More)
A thorough understanding of the microscopic mechanism of excited-state proton transfer (ESPT) and the influence of the solvent environment on its dynamics are of great fundamental interest. We present here a detailed investigation of an ESPT to solvent (DMSO) using time-resolved broadband fluorescence and transient absorption spectroscopies. All(More)
Singlet-singlet energy transfer in self-assembled via axial coordination of imidazole-appended (at different positions of one of the meso-phenyl entities) free-base tetraphenylporphyrin, H(2)PIm, to either zinc phthalocyanine, ZnPc, or zinc naphthalocyanine, ZnNc, dyads is investigated in noncoordinating solvents, o-dichlorobenzene and toluene, using both(More)
Complex formation and intermolecular excited-state proton transfer (ESPT) between a dihydroxy-1,8-naphthalimide photoacid and organic bases are investigated in polar aprotic solvents. First, quantum chemical calculations are used to explore the acid-base and spectroscopic properties and to identify energetically favorable complexes. The two hydroxyl groups(More)
5-(Diphenylphosphanyl)-10,15,20-triarylporphyrins (meso-phosphanylporphyrins) underwent complexations with palladium(II) and platinum(II) salts to afford phosphapalladacycle- and phosphaplatinacycle-fused coplanar porphyrin dimers, respectively, via regioselective peripheral β-C-H activation of the meso-phosphanylporphyrin ligands. The optical and(More)
There is broad interest in molecular encapsulation as such systems can be utilized to stabilize guests, facilitate reactions inside a cavity, or give rise to energy-transfer processes in a confined space. Detailed understanding of encapsulation events is required to facilitate functional molecular encapsulation. In this contribution, it is demonstrated that(More)
Polar solvation dynamics of six 7-aminocoumarins and 4-aminophthalimide (4AP) are investigated using broadband FLuorescence UP-conversion Spectroscopy (FLUPS) combined with a global analysis based on time-dependent band-shape functions. The solvation dynamics of the coumarins in ethanol exhibit only minor differences but are, however, significantly(More)