Chromophores propeller shaped

D. Octupolar/ Propeller Shaped Chromophores with Large Two-Photon Absorptivity... 

Donor-7i)3-Donor chromophores are another group of propeller-shaped chromophores. TPA studies of 117 indicated only a small 5 of 30 GM at 740 nm. The shape of the excitation spectrum showed that the maximum must be located at X < 740 nm [505]. Chromophore 117 has an amino nitrogen at the central core as donor, which combines three unsaturated arms with end capped amino... 

D-7i-A)3-D chromophores exhibit large TPA, as shown for chromophore 122 [490]. This compound can be considered a propeller-shaped molecule consisting of three quadrupolar arms. This study demonstrates that addition of each individual arm results in a twofold increase of 8 as shown for the TPA of 122 (5 = 5030 GM) in comparison with the quadrupolar chromophore 100c (7) = 1370 GM). The latter comprises one arm of 122. Substitution of one arm by a methyl group results in a twin chromophore exhibiting a 8 of 3130 GM. Thus, one can conclude that TPA depends on the number of arms (na), na > 2, incorporated in both (D-rc- A)na-D and (D-7i)na-D chromophores. The structural pattern of 122 comprises three quadrupolar arms. Thus, Eqs. (59) and (60) cannot be applied to describe TPA of 122 because A/(m 0 due to the quadrupolar pattern of each arm. Therefore, the enhacement of 8 is better explained by the increase of the transition dipole moments Mqi and M 2 because... 

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