H. Le Bozec

Preparation and characterization of ruthenium complexes with the new 4,4′,4″-tri-tert-butylterpyridine ligand and with 4,4′-di-tert-butylbipyridine

Abstract An efficient procedure for the preparation of 4,4′,4″-tri- tert -butylterpyridine (trpy*) which is formed together with 4,4′-di- tert -butylbipyridine (bipy*) is described, and the preparation of the complexes (trpy*)RuCl 3 , [(trpy*)L 2 RuCl]PF 6 (L 2 = bipy, bipy*), and (bipy*) 2 RuCl 2 and their characterization by cyclic-voltametry, UV—vis and 1 H NMR spectroscopy are reported. It is shown that introduction of tert -butyl substituents increases the solubility of the resultant complexes and enhances the electron donating influence of the trpy ligand.

Sulfur-containing carbene-metal compounds: General route from carbon disulfide manganese complexes; X-ray structure of 1,3-dithiol-2-ylidenemanganese(I) derivative

Abstract Chiral carbene-manganese(I) complexes have been synthesized by the cyclo-addition of dimethyl acetylenedicarboxylate to the coordinated CS 2 ligand in Mn(η 2 -CS 2 )(CO)(L)C 5 H 4 R (L = P(OMe) 3 ; PMe 2 Ph; PMe 3 ). Irrespective of the nature of the ligand L, these 1,3-dithiol-2-ylidenemanganese(I) complexes are stable towards isomerisation into heterometallocycles and exhibit low frequency carbonyl absorption bands in the infrared consistent with a strong electron releasing effect of the carbene ligand. The structure of Mn(CS 2 C 2 (CO 2 Me) 2 )(CO)(P(OMe) 3 )(C 5 H 5 ) has been determined by X-ray analysis of a suitable crystal. The molecule shows a carbene carbonmanganese bond C(7)Mn of length 1.876 A and a planar carbene which does not adopt the 1,3-dithiolium aromatic-ring geometry but contains a carboncarbon double bond, C(8)C(9), of length of 1.341 A. The CO 2 Me groups are out of the plane of the carbene ligand and two positions with equal occupancy are found for each oxygen atom O(3) and O(5) belonging to the CO groups.

Coordination chemistry for nonlinear optics: a powerful tool for the design of octupolar molecules and supramolecules

Metal ions such as ruthenium(II) are excellent templates for building 3D octupolar nonlinear optical (NLO)-phores. Their associations with bipyridyl ligands give rise to octahedral metal complexes with large first-order hyperpolarizabilities. The ability to functionalize these octupoles allows their incorporation into macromolecular architectures such as polyimides and metallodendrimers. The quadratic NLO susceptibilities β of these supramolecules are characterized by harmonic light scattering performed at the near-IR 1.91 μm fundamental wavelength, in order to rule out two-photon fluorescence contributions to the harmonic signal. Comparison with a linear polymer clearly demonstrates a quasi-optimized octupolar supramolecular ordering in a dendrimer made of seven ruthenium(II) complexes.

Derives heterodinucleaires pontes par le sulfure de carbone FeCS2Mn et FeCS2 Mo. Utilisation de complexes η2-CS2-Fer comme ligands

Abstract Heterodinuclear complexes containing a CS 2 bridge were formed by displacement of a weakly bonded ligand to manganese(I) and molybdenum(O) by Fe(η 2 -CS 2 )(CO) 2 L 2 derivatives. It is shown that carbon disulphide is η 2 -bonded to iron and σ-bonded to manganese by 13 C NMR spectroscopy and that the CS 2 bridge allows electron transfer from iron to manganese.

η2-dithiomethyliron(II) ionic complexes. Evidence for a strong dependence on the nature of the trans-phosphorus ligands bonded to iron

Abstract Cationic η 2 -dithiomethyliron(II) complexes have been made by alkylation of the uncoordinated sulfur atom of Fe(CO) 2 [η 2 -CS 2 ](L) 2 . Surprisingly, only when the phosphorus ligands L are strong donors (PMe 3 , PMe 2 Ph) does coordination of iodide take place to give the neutral Fe(η 2 -CS 2 CH 3 )(I)(CO)(L) 2 derivatives. The 13 C NMR spectra of the latter at 215 K indicated the presence of both isomers when L was PMe 2 Ph. Reaction with iodine under carbon monoxide regenerated the cationic precursor.

Carbon disulphide iron complexes as a source of bis(trifluoroacetato)iron derivatives

Abstract Treatment of complexes of the type Fe(η 2 -CS 2 )(CO) 2 L 2 with trifluoroacetic acid provides a convenient route to Fe(η 1 -OCOCF 3 ) 2 (CO) 2 L 2 derivatives (L = PPh 3 , PMe 2 Ph, Download full-size image ). The latter react with (NO) + PF 6 − in acetonitrile to give NO and [Fe(gh 1 -OCOCF 3 )(NCCH 3 )(CO) 2 L 2 ] PF 6 complexes.

Highly efficient supramolecular self-assembly with octupolar symmetry for quadratic nonlinear optics

Summary form only given. 3-D octupolar molecules and molecular arrangements represent the right match between nonlinear tensorial properties and stereochemistry, especially in the realm of organometallics. Moreover, the 3-D character of octupolar nonlinear molecules are expected to be particularly suitable for the formation of supramolecular dendrons. As the ruthenium-tris-bipyridine building blocks of various organometallic dendrimers may display large octupolar /spl beta//sub J=3/ hyperpolarizabilities, an octupolar spontaneous supramolecular order would be of great interest for nanoscale quadratic NLO. We have synthesized various dendrimer-like oligomers containing N (N = 1, 2, 3 and 7) monomeric ruthenium tris-bipyridine derivatives. A linear ruthenium-tris-bipyridine sidechain-functionalized oligointide (N = 14) is also synthesized and investigated for comparison. The quadratic NLO hyperpolarizabilities of these supramolecules were characterized by harmonic light scattering in order to rule out 2-photon fluorescence contributions to the harmonic signal.