No abstract

International audienceThe 2,7-fluorenyl-bridged Fe(?5-C5Me5)(?2-dppe)[C≡C(2,7-C13H6Bu2)C≡C]Fe(?5-C5Me5)(?2-dppe) (1a), its extended analogue Fe(?5-C5Me5)(?2-dppe)[C≡C(1,4-C6H4)C≡C(2,7-C13H6Bu2)C≡C(1,4-C6H4)C≡C](?5-C5Me5)(?2-dppe)Fe (1b), and the corresponding mononuclear complexes Fe(?5-C5Me5)(?2-dppe)[C≡C(2-C13H7Bu2)] (2a) and Fe(?5-C5Me5)(?2-dppe)[C≡C(1,4-C6H4)C≡C(2-C13H7Bu2)] (2b), which model half of these molecules, have been synthesized and characterized in their various redox states. The molecular wire characteristics of the dinuclear complexes were examined in their mixed-valent states, with progression from 1a[PF6] to 1b[PF6] resulting in a sharp decrease in electronic coupling. The cubic nonlinear optical properties of these species were investigated over the visible and near-IR range, a particular emphasis being placed on their multiphoton absorption properties; the complexes are shown to function as redox-switchable nonlinear chromophores at selected wavelengths, and the more extended derivatives are shown to exhibit the more promising NLO performanc

International audienceFour new mononuclear alkynyl complexes each featuring a terminal 2-fluorenyl group, namely Fe(η5-C5Me5)(CO)2[C≡C(2-C21H25)] (2), Ru(κ2-dppe)2Cl[C≡C(2-C21H25)] (3), Ru(κ2-dppe)2[C≡C(4-C6H4NO2)][C≡C(2-C21H25)] (4), and [Fe(η5-C5Me5)(κ2-dppe)_C≡C(C5H4N)-CH2(2-C13H9)_][PF6] (5[PF6]), have been synthesized and characterized, and their redox, absorption, and emission properties have been studied. For the two ruthenium derivatives 3 and 4, these studies are complemented by spectroelectrochemical investigations, Z-scan measurements, and DFT calculations. Fluorimetric studies reveal that these compounds are poorly or not luminescent, and, when luminescent, that the detected weak luminescence most likely originates from a higher lying ligand-centred (LC) excited state presumably located on fluorene. Finally, the third-order nonlinear optical (NLO) properties of 3 and 4 are reported. It is shown that the bis-alkynyl complex 4 is significantly more active than 3 and that both compounds exhibit two-photon absorption (TPA) around 860–1050 nm, with TPA cross-sections above 350 GM. In addition, it is shown that both species should give rise to a marked switching of their cubic NLO properties in this spectral range upon oxidation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

No abstract

No abstract