Photoinduced Electron Transfer Processes in 1,8-Naphthalimide-Linker-Phenothiazine Dyads

Abstract

Photoinduced electron transfer (PET) processes of 1,8-naphthalimide-linker-phenothiazine (NI-L-PTZ) dyads have been investigated using the nanosecond- and picosecond-transient absorption measurements. Two kinds of linker were introduced, i.e., polymethylene-linked dyad (NI-C8-PTZ and NI-C11-PTZ) and a poly(ethyl ether)-linked one (NI-O-PTZ). The 355 nm pulsed laser excitation of NI-C8-PTZ, NI-C11-PTZ, and NI-O-PTZ in acetonitrile produced NI radical anion (NI*-) and PTZ radical cation (PTZ*+) with the absorption bands around 420 and 520 nm, respectively, through charge transfer from PTZ to NI in the singlet excited state (NI(S1)) as well as in the triplet excited states (NI(T1)) in acetonitrile. On the other hand, the charge transfer process occurred only from NI(S1) in nonpolar solvents. The rates of charge transfer and charge recombination processes largely depended on the solvent polarity and they are affected by the length of linkers and electronic coupling through polyether linker. The PET mechanism is discussed in terms of the free energy change for the charge transfer.

Synthesis, Optical Characteristics and Complex Formation of Molecular Receptors Based on 1,8-Naphthalimide Derivatives in Solution and in Composition of Hybrid Tin Dioxide Nanoparticles

“…As expected the addition of metals salts (Cu(ClO 4 ) 2 remarkable changes in position of the long wavelength bands in the absorption and fluorescence spectra, but in the case of Hg…”

“…After the reaction mixture was cooled to room temperature, the catalyst was filtered off, the filtrate was evaporated in vacuo. The residue was purified by column chromatography (silica gel, eluent PhH-EtOH, gradient elution) to yield 23 mg (16 % (1) 6-(2- (2,3,5,6,8,9,11, [1,4,10,7,13] …”

“…Studies have shown that the introduction of the two sulfur atoms in the crown ether receptor leads to ligands selective towards the Hg 2+ and Pb 2+ cations in the presence of alkali, alkaline earth and some heavy metal ions (AgClO 4 , Ni(ClO 4 ) 2 Molecular Receptors Based on 1,8-Naphthalimide Derivatives in SI). Similar to compound 2b crown containing carboxyl derivative 4b shows a low level of fluorescence due to the concurrent efficient photoinduced electron transfer process ( Figure 6).…”

“…In the past two decades, much progress has been achieved due to the development of optical chemosensors containing a selective receptor, and a signaling moiety capable of changing its spectral characteristics as a result of complex formation. [2] The functionalization of nanostructured solids with specific groups to enhance active functions, such as the recognition of guests or to switch surface properties, is particularly interesting. Such materials with a high and readily accessible specific surface can amplify certain functional chemical processes.…”

Intra- and Interlayer Energy Transfer in Planar Systems Based on Amphiphilic Naphthalimide Derivatives

“…[7] Фотофизические свойства производных нафтали-мида привлекают значительное внимание исследовате-лей не только благодаря своим функциональным харак-теристикам. Наличие у нафталимидного ядра электроно-акцепторных свойств в возбужденном состоянии делает эти соединения удобными моделями для изучения распространенных в живой природе процессов фотоин-дуцированного переноса электрона, [8,9] а также процес-сов безызлучательного резонансного переноса энергии электронного возбуждения по механизму Г. Фёрстера (Forster Resonance Energy Transfer, FRET). [10][11][12][13][14][15][16] В связи с этим большой интерес представляют возможности исследования механизмов FRET-процессов, открываю-щиеся при использовании модельных бисхромофорных систем, состоящих из высокоорганизованных мономоле-кулярных слоев соединений данного типа, с контролиру-емыми условиями сборки.…”