Impact of the Subunit Arrangement on the Nonlinear Absorption Properties of Organometallic Complexes with Ruthenium(II) σ-Acetylide and Benzothiadiazole as Building Units §

Authors :: Claudia Dragonetti
Dominique Roberto
Eleonora Garoni
Alessia Colombo
Kenji Kamada
Source :: Inorganics, Vol 7, Iss 5, p 67 (2019), Inorganics, Volume 7, Issue 5
Publication Year :: 2019
Publisher :: MDPI AG, 2019.
Abstract: In this paper, the nonlinear absorption properties of two complexes consisting of Ru(C&equiv CPh)(C&equiv C)(dppe)2 (dppe = Ph2PCH2CH2PPh2) as electron donor (D) and 4,7-di(2-thienyl)benzo[c][1,2,5]thiadiazole as electron acceptor (A) units in two different arrangement, i.e., A&ndash D&ndash A and D&ndash A&ndash D, are presented. They were measured in solution by the femtosecond open-aperture Z-scan method. The complexes show moderate two-photon absorption cross-sections &sigma (2) of several hundred to one thousand GM (here 1 GM = 10&minus 50 cm4 s molecule&minus 1 photon&minus 1). Although they are formed by the same building units, it was found that the two-photon absorption values of the D&ndash D arrangement are six times higher than that of the A&ndash A one. This difference can be explained by the number of metal cores (one or two ruthenium centers), the geometrical configurations of the complexes (more or less planar), and the resonance enhancement by lowering the intermediate state.

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