Triarylamine dendrimers

All of the monodendrons 395-397 and dendrimers 398-400 exhibit apparently identical violet-blue light emission with two maxima at 373 and 390 nm. Triarylamine dendrimers with terminal 2,5-diarylthiophene moiety have been synthesized (03JA8104). 

Goodson and co-workers investigated excitation energy transfer processes in nitrogen cored distyrylbenzene and triarylamine dendrimer systems (Fig. 1.5) by photon echo and polarized fluorescence upconversion spectroscopy. Observed components of less than 1 ps were attributed to a coherent energy transport mechanism. The contributions from his group were recently summarized [15],... 

An interesting electrochemical and spectroelectrochemical behavior has been reported for zinc porphyrin-cored triarylamine-dendrimers of first and second generation [131]. The first-generation dendrimer was oxidized by a total of 6e that were assigned to (i) le oxidation of the zinc porphyrin generating the monocation radical (ii) le oxidation of one of the triarylamine units and (iii) a 4e oxidation process attributed to the three remaining triarylamine units and to the oxidation of the zinc porphyrin to the dication species. The zinc porphyrin ring oxidation... 

Moore et al. later reported [98] the design and synthesis of triarylamine based dendrimers. These fluorescent macromolecules exhibited reversible redox processes and their potential use in electro-optic film applications was envisioned. 

Hartwig first reported the arylation of diarylamines using both (o-to jP/Pd-and DPPF/Pd-catalysts, Eq. (33) [29,64]. The Yale group utilized the (o-tol jP/Pd-and DPPF/Pd-based protocols for the preparation of triarylamine-containing dendrimers and cyclophanes, respectively. 

Dendrimer encapsulated pentathiophenes 142-144 have been synthesized. The core pentathiophene and peripheral triarylamines have been shown to simultaneously emit light <03JA13165>. This provides a good model for single layer multichromic organic light-emitting... 

Cyclic voltammetry in THF of the triarylamine-based dendrimer 68 indicated the presence of at least four unresolved waves, giving rise to delocalized radical cations [138]. 

It should be noted here for triarylamine networks and dendrimers [104], respectively, the radical cations have interesting properties like the formation of high-spin polyradicals with ferromagnetic coupling [105] or conducting polymers [106]. Very often, triarylamines have been used as the hole-transport layer in electroluminescent devices [107]. 

Scheme 29 Dye-labeled dendrimers with triarylamine peripheries for OLEDs by Fr chet and coworkers [88,89]...

A. Petrella, J. Cremer, L. De Cola, P. Bauerle and R. M. WiUiams, Charge transfer processes in conjugated triarylamine-oligothiophene-perylenemonoimide dendrimers, J. Phys. Chem. A, 109, 11687-11695 (2005). 

Other important feature of triarylamine-zinc porphyrin dendrimers is the intramolecular energy transfer from the triarylamine moieties to the zinc porphyrin unit. Interestingly, zinc porphyrin fluorescence emission takes place with higher quantum yield upon excitation in the triarylamine moieties UV absorption bands than upon direct excitation of the ZnTPP unit. Similar antenna effect has been previously reported for a series of carbazole-porphyrin dendrimers [132] encompassing up to 21 redox centers. Their electrochemical pattern is strongly dependent on the way the carbazole are structured along the dendrimer branches and connected to the porphyrin core. 

Huang C-Y, Su YO (2010) Spectral and redox properties of zinc porph5nin core dendrimers with triarylamines as dendron. Dalton Trans 39(35) 8306-8312... 

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