Hubert Le Bozec

Dipolar and Non‐Dipolar Pyridine and Bipyridine Metal Complexes for Nonlinear Optics

Metal complexes of pyridine and bipyridine-type ligands represent an important class of nonlinear optical (NLO) materials: (i) They can incorporate a variety of functionalised ligands with a wide range of metals which can give rise to tuneable NLO properties; (ii) they are generally associated with intense low-lying charge-transfer excitations such as metal to ligand charge-transfer (MLCT) or intraligand charge-transfer (ILCT); (iii) bipyridyl ligands are also good building blocks that allow the construction of octupolar complexes with a defined geometry and symmetry. This review describes the recent developments in the design of such dipolar and octupolar chromophores for second-order nonlinear optics.

Organometallic chemistry of arene ruthenium and osmium complexes

Publisher Summary This chapter focuses on the organometallic chemistry and new aspects of arene ruthenium and osmium complexes. It explores that arene ruthenium and osmium complexes play an increasingly important role in organometallic chemistry. They appear to be good starting materials for access to reactive arene metal hydrides or 16-electron metal (0) intermediates that have been used recently for carbon-hydrogen bond activation. Various methods of access to cyclopentadienyl, borane, and carborane arene ruthenium and osmium complexes have been reported. Recently, from classic organometallic arene ruthenium and osmium chemistry has grown an area making significant contributions to the chemistry of cyclophanes. These compounds are potential precursors of organometallic polymers, which show interesting electrical properties and conductivity. The possibility of coordination of a two-electron ligand, in addition to arene, to the ruthenium or osmium atom provides a route to mixed metal or cluster compounds. Cocondensation of arene with ruthenium or osmium vapors has recently allowed access to new types of arene metal complexes and clusters. It reviews that arene ruthenium and osmium appear to be useful and specific catalyst precursors, apart from classic hydrogenation, for carbon–hydrogen bond activation and activation of alkynes; such compounds may become valuable reagents for organic syntheses.

Design and synthesis of 4,4′-π-conjugated[2,2′]-bipyridines: a versatile class of tunable chromophores and fluorophores

A series of 4,4′-disubstituted[2,2′]-bipyridines, featuring π-conjugated substituents such as donor-(acceptor-) substituted styryl, thienylvinyl, phenylimino and phenylazo groups, have been synthesized. X-Ray structures are provided for three ligands containing –CC–, –CN– and –NN– linkers, respectively. These chromophores display good to excellent thermal stabilities with decomposition temperatures of up to 350°C. The strong influence of the nature of the endgroups and π-linkers on the optical properties is discussed. The stepwise protonation of 4,4′-dibutylaminostyryl-[2,2′]-bipyridine and its coordination behavior to different metallic moieties [Zn(II), Hg(II), Pd(II), Re(I), Re(VII)] have also been investigated. It is found that the absorption and emission maxima can be easily tuned by these exogenous additives over a wide range of wavelengths (360

Cyclometallated platinum(II) complexes incorporating ethynyl–flavone ligands: switching between triplet and singlet emission induced by selective binding of Pb2+ ions

Platinum-ethynylflavone complexes featuring various polyether arms display 3IL phosphorescence associated with the appended flavone perturbed by the platinum centre (tau approximately 20 micros), but switch dramatically to flavone-localised 1IL fluorescence (tau approximately 2 ns) upon selective binding of Pb2+.

Modulating the luminescence of an iridium(III) complex incorporating a di(2-picolyl)anilino-appended bipyridine ligand with Zn2+ cations

A novel iridium complex incorporating a di(2-picolyl)anilino-appended bipyridine ligand was synthesized and its optical properties studied. The presence of Zn2+ ions specifically perturbs the excited state, giving rise to a blue-shifted absorption and emission, and a shorter luminescence lifetime.

Heteroleptic copper(I)–polypyridine complexes as efficient sensitizers for dye sensitized solar cells

The synthesis and the physico-chemical characterization of HETPHEN based heteroleptic copper(I)–bis(diimine) complexes are reported. For TiO2 based dye sensitized solar cells (DSCs), the latter display impressive photoconversion efficiencies (PCEs), unprecedented for first row transition metal coordination complexes.

EFFICIENT SYNTHESIS OF NEW NITROGEN DONOR CONTAINING TRIPODS UNDER MICROWAVE IRRADIATION AND WITHOUT SOLVENT

Five new N,N-bis(pyrazole-1-yl-methyl) alkylamines have been prepared in one step by condensation of two equivalents of 1-(hydroxymethyl)-3,5-disubstituted pyrazoles with a series of primary amines. This reaction is carried out under microwave irradiation (60 W) in the absence of solvent for 20 m and affords high yields (75–90%) of mixed nitrogen donor tripodal molecules.

Synthesis and characterization of ruthenium(II) complexes containing the new tridentate ligand 4,4′,4″-tri-tert-butyl-terpyridine

Abstract The synthesis of coordination compounds of ruthenium(II) containing the new tridentate ligand 4,4′,4″,-tri-tert- butyl-terpyridine (trpy*) is reported. Trpy* has been prepared in up to 50% yield from tert-butyl-pyridine, and easily separated from 4,4′-di-tert-butyl-bipyridine (bpy*). A series of complexes [(trpy*)(L2)RuX]+ (L2bpy; bpy*; X−Cl−, CF3SO3−) and [(trpy*)(L2)RuOH2]2+ (L2bpy; bpy*) were obtained from (trpy*)RuCl3. Individual complexes have been characterized by elemental analyses, 1H NMR and UV-Vis spectroscopies, and cyclic voltammetry.

Linear and nonlinear optical properties of tris-cyclometalated phenylpyridine Ir(III) complexes incorporating π-conjugated substituents.

The synthesis, luminescence, and nonlinear optical properties of a new series of Ir(ppy)3 (ppy = 2-phenylpyridine) complexes incorporating π-extended vinyl-aryl substituents at the para positions of their pyridine rings are reported. Appropriate substitution of the pyridyl rings allows the tuning of the luminescence properties and the second-order nonlinear optical response of this unusual family of three-dimensional chromophores. Theoretical calculations were performed to evaluate the dipole moments, to gain insight into the electronic structure, and to rationalize the observed optical properties of the investigated complexes.

First lanthanide dipolar complexes for second-order nonlinear optics

New push-pull NLO-phores based on lanthanide complexes (Ln = La, Gd, Dy, Yb) featuring an annelated dibutylaminophenyl functionalised terpyridyl ligand have been synthesised and shown to exhibit large first-order hyperpolarizability.