کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5186175 1381097 2009 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Photochemical and photophysical reactions of poly(propylene imine) dendrimers tethering cinnamamide groups
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Photochemical and photophysical reactions of poly(propylene imine) dendrimers tethering cinnamamide groups
چکیده انگلیسی

Here we report on photochemical and photophysical properties of poly(propylene imine) dendrimers tethering cinnamamide groups at the peripheral positions. Photoexcitation of the dendrimer solutions with 313 nm brought about monotonous decrease of absorption band of trans-cinnamamide around 270 nm as a result of trans-to-cis photoisomerization and [2+2] photocycloaddition. The first-generation dendrimer showed preferential formation of cis-isomer, whereas photocycloaddition was more favorable for the third- and fifth-generation dendrimers. Interestingly, the third- and fifth-generation dendrimers could encapsulate phosphorescent donors into the dendrimer nanocavities. When the dendrimers capturing the donors were excited at 365 nm, photocycloaddition proceeded efficiently through triplet-triplet energy transfer. By analyzing phosphorescence spectra with theoretical Perrin's formula, we found that this triplet-triplet energy transfer is quenched within a radius of ∼0.5 nm. Such triplet-triplet energy transfer within dendrimer nanocavities would provide promising strategy to design and fabricate novel molecular devices by utilizing the dendrimers.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 50, Issue 13, 19 June 2009, Pages 2944-2952
نویسندگان
, , , ,