Octupolar and Other Multibranched Dyes

However, for molecule oc.2 with R3 and diphenylamine donors the largest cross section (i5n 2.6 X 10 GM) was observed at 800 nm, for the transition into a higher-lying state [119]. 

The degree of intermolecular charge transfer can be expected to be smaller in compound oc.5 than in compounds oc.2 and oc.4, because oc.5 does not have the three cyano substituents. The 2PA spectrum of oc.5 shows a broad band around 770 nm, with 3max = 3.8 x 10 GM [121]. Even if a direct comparison with the oc.2 series [119] is not possible because of the different nature of the conjugated linker and of the solvent used in the experiment, the cross section of oc.5 is significantly smaller than for oc.2 with the R2 branch (which is shorter than the branch in oc.5) and a dialkylamino substituent (W= 1.4x103 gm[119]). 

The second series of molecules, oc.9-11, was described by Katan et al. and is characterized by arms with a D- 7r-A structure (class V of Fig. 8), where the 

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