Linear and Third-Order Nonlinear Optical Properties of Fe(n5-C5Me5)(k2-dppe)- and trans-Ru(k2-dppe)2-Alkynyl Complexes Containing 2-Fluorenyl End Groups

The synthesis and characterization of a set of redox-active iron and ruthenium alkynyl complexes of general formula [[M]Cl(1–p){C≡CC6H5–m(C≡CFlu)m}(1+p)][PF6]n are reported (n = 0–1; m = 1–2; [M] = [Fe(η5-C5Me5)(κ2-dppe)] and p = 1 or [M] = [trans-Ru(κ2-dppe)2] and p = 0–1). The linear and third-order nonlinear optical properties of these new organometallic complexes featuring phenylalkynyl ligands functionalized by 2-fluorenyl (Flu) groups were studied in their stable redox states. Their first electronic transitions are assigned with the help of DFT calculations. We show here that these compounds possess significant third-order NLO responses in the near-IR range for molecules of their size. In particular, the remarkably large 2PA activities of the new Ru(II) compounds in the 600–800 nm range (Z-scan) make them attractive nonlinear chromophores. Structure–property studies emphasize the importance of para- versus meta-connection of the 2-fluorenylethynyl units on the phenylalkynyl core and reveal that upon progressing from mono- to bis-alkynyl complexes a further increase of the 2PA cross section can be obtained while maintaining linear transparency in the visible range

Octupolar platforms for applications in Non Linear Optics

During this Ph.D work, we were able to synthesize a series of 2D octupoles as well as study their linear and nonlinear optical properties. These molecular architectures are known for their good NLO properties, especially their two-photon absorption properties (TPA). In this thesis, we focused most of our work on isocyanurate and triazine cored octupoles. Isocyanurates are quite understudied even though they have recently proven to be promising for TPA applications, whereas triazines were already known for their good TPA properties. In this respect we started out by the synthesis and characterization of a series of organic isocyanurates. These compounds allowed us to derive useful structure/property relationships. We also synthesized a series of analogous triazines possessing the same donor groups than the isocyanurate series, in order to be able to compare the effect of the core in these two series. This study allowed us to select two candidate chromophores for one of the applications of TPA, two-photon photodynamic therapy (2PPDT). We then focused our efforts on making hydrosoluble version of our model compounds for 2PPDT. Thanks to a collaboration with the group of Magali Gary-Bobo and Manuel Garcia (UMR 6247, Montpellier), photosensitization and biocompatibility results have been obtained in vitro and in vivo. In the last part of this work, the structure/property relationships derived on organic molecules have been used to design a new series of cyclometalated platinum complexes

2,7-Fluorenediyl-Bridged Complexes Containing Electroactive "fe(η⁵-C₅Me₅)(k²-dppe)C=C-" End Groups: Molecular Wires and Remarkable Nonlinear Electrochromes

The 2,7-fluorenyl-bridged Fe(η5-C5Me5)(κ2-dppe)[C≡C(2,7-C13H6Bu2)C≡C]Fe(η5-C5Me5)(κ2-dppe) (1a), its extended analogue Fe(η5-C5Me5)(κ2-dppe)[C≡C(1,4-C6H4)C≡C(2,7-C13H6Bu2)C≡C(1,4-C6H4)C≡C](η5-C5Me5)(κ2-dppe)Fe (1b), and the corresponding mononuclear complexes Fe(η5-C5Me5)(κ2-dppe)[C≡C(2-C13H7Bu2)] (2a) and Fe(η5-C5Me5)(κ2-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 performance