Dual luminescence

Other first-generation dendrimers built around multichelating ligands are the trinuclear complexes 29 - 38 [50-52] and several hexanuclear complexes (for representative examples, see 39 and 40) [53]. In all of these compounds, the photophysical properties are equivalent to those of their building blocks. In the mixed-metal complexes 31 and 34 [50b] the Ru(II)- and Os(II)-based chromo-phores are only weakly-coupled and a dual luminescence is observed. 

Cowley DJ, Peoples AH (1977) Rotational isomerism and dual luminescence in dipolar dialkylamino-compounds. J Chem Soc Chem Commun 352-353... 

Stich MIJ, Nagl S, Wolfbeis OS, Henne U, Schaeferling M (2008) A dual luminescent sensor material for simultaneous imaging of pressure and temperature on surfaces. Adv Funct Mater... 

Photoinduced electron transfer from eosin and ethyl eosin to Fe(CN)g in AOT/heptane-RMs was studied and the Hfe time of the redox products in reverse micellar system was found to increase by about 300-fold compared to conventional photosystem [335]. The authors have presented a kinetic model for overall photochemical process. Kang et al. [336] reported photoinduced electron transfer from (alkoxyphenyl) triphenylporphyrines to water pool in RMs. Sarkar et al. [337] demonstrated the intramolecular excited state proton transfer and dual luminescence behavior of 3-hydroxyflavone in RMs. In combination with chemiluminescence, RMs were employed to determine gold in aqueous solutions of industrial samples containing silver alloy [338, 339]. Xie et al. [340] studied the a-naphthyl acetic acid sensitized room temperature phosphorescence of biacetyl in AOT-RMs. The intensity of phosphorescence was observed to be about 13 times higher than that seen in aqueous SDS micelles. 

Lee, S.J., Luman, C.R., Castellano, F.N. and Lin, W. (2003) Directed assembly of chiral organometallic squares that exhibit dual luminescence. Chem. Commun.,2124—2125. 

The dual luminescence bands exhibited by the M(CO)4(a,a/-diimine) complexes in room-temperature solution are unusual and have been further explored by excitation wavelength studies [60], The higher energy emission band is seen to increase substantially in intensity as shorter exciting wavelengths are used... 

Mixed clusters Eu c NagEus-jcYbt. with x = 4 or 5 (see fig. 100), in which the central site is occupied by Eum whereas the Yb111 ions are statistically distributed in the peripheral sites, are isostructural with the NagLng species. They display dual luminescence from Eum and Ybm, an interesting property despite the fact that the quantum yield of the Yb111 luminescence... 

The formation of a (U204H4+) exciplex has recently been suggested to occur in 10-2M HNO3 solution where dual luminescence was observed224). 

The complexes K[Au(CN)2] and K[Ag(CN)2] in water and methanol displayed intense luminescence that was dependent on the concentration, solvent, temperature, and excitation wavelength. The emission spectra of the gold complex in aqueous solution at ambient conditions showed dual luminescence at ca. 400 410nm (HE band) and 430-470inn (LE... 

Under jet-cooled conditions, no long-wave emission is observed for a series of the D-A compounds that show dual luminescence in solutions, except III (Figure 2). The observed broad emission (Figure 8) of the latter, highly pretwisted , molecule is a manifestation of the overlap of two fluorescences, a and b (Figure 3). The longwave emission a dominates upon direct excitation to the CT state and the intensity... 

Solute-solvent complexes of different stoichiometry have been observed between all the D-A compounds under consideration and various solvent molecules. Some of the clusters show structured excitation spectra and a narrow short-wave emission that has been assigned to the primary excited state of the vdW complex. The broad, red-shifted emission of other clusters can be explained in terms of the transformation of the vdW complexes of stoichiometry l n (n > 0) into excimers or the transition into an intramolecular CT state of the D-A chromophore which is induced by its polar partner(s) (for the complexes of stoichiometry 1 ). The main conclusion from the fluorescence behaviour of the jet-cooled vdW clusters is that dual luminescence is obviously connected with the preference of specific solute-solvent geometries. 

Besides, a tetranuclear copper(I) cluster [Cu4 S2P(0 Pr)2 4] (15) with dialky Idithiophosphate as ligands has also been reported to be luminescent [88]. The solid-state emission of the complex occurs at 547 nm at 298 K. At 77 K, dual luminescence at 573 and 647 nm has been observed. 

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