ORGANOMETALLIC LIGANDS: A NEW STRATEGY TO CONSTRUCT LUMINESCENT ASSEMBLIES FOR OPTOELECTRONICS – OPTOELECTR-OM

The expected results will be obtained, thanks to the methods developed since several years in the group. These methods are based on the « bottom-up » approach for the elaboration of luminescent molecular materials. The latter are prepared by treatment of luminophors based on ruthenium, rhodium and iridium with the assembling ligands based on metal-stabilized quinones, thioquinones and selenoquinones and according to the know-how of the group. Thus we expect to modify profoundly the photophysical properties of the chromophores in order to obtain a novel generation of molecules for applications in the optoelectronic and photovoltaic domains.

In a second approach we developed the synthesis of novel organometallic ligands with planar chirality. In fact these optically active ligands were prepared with a carbinol function. Such ligands display a sulfur or phosphine coordinating center and possess (Sp, S) or (Rp, R) configurations. These organometallic ligands pave the way for novel perspectives for the enantioselective preparation of coordination complexes, which might show interesting luminescent properties.

The research perspectives lie within the frame of the current project. In fact with the collaboration of professor Vivian W. W. Yam (partner 4), we wish to develop the synthesis of luminescent coordination assemblies with the organometallic ligands para-dithiobenzoquinone and para-diselenobenzoquinone.These Ligands are capable of binding to two molecular luminophors of the type Pt(terpy) or/and Pt(CF3-N^C^N) (N^C^N = 1,3-bispyridylbenzene) to generate trinuclear complexes displaying Pt---Pt and ?-? interactions in the solid state. On the other hand with the collaboration of the two other partners we wish to prepare emitters le in the near infrared region at room temperature for future applications in the domain of photovoltaic and l’optoelectronic.

1-A. Damas, B. Ventura, J. Moussa, A. Degli Esposti, L.-M. Chamoreau, A. Barbieri, H. Amouri Inorg. Chem. 2012, 51, 1739. 2- J. Dubarle-Offner, M. R. Axet, L. M. Chamoreau, and H. Amouri Organometallics 2012, 31, 4429. 3-A. Damas, L.-M. Chamoreau, A. L. Cooksy, A. Jutand and H. Amouri Inorg. Chem. 2013, 52, 1409.

Polyphenylpyridyl coordination complexes of ruthenium(II), rhodium(III), iridium(III), platinum(II) and gold(III) constitute an important class of chromophores because of their unique photophysical properties. This kind of chromophoric bricks have found important applications as biological probes, sensors, antitumor agents, sensitizers in Graetzel cells and also as emitters in optoelectronics (OLEDs). This class of chromophores are of great technical and economical importance and were therefore highly investigated in the last years and are among the most studied organometallic compounds. Many of such compounds were described in the literature and some of them, especially with platinum(II) and iridium(III) have found applications in the area of OLEDs to build LCD screens.
From a practical point of view, the energy and intensity of the emission can be tuned by simply either functionalizing the phenylpyridine ligands and/or modifying the organic ancillary ligands. In this context, many functionalized phenylpyridyl and ancillary organic ligands were screened to solve specific scientifical, technical and economical problems. Despite prodigious accomplished progresses in this field, several important research activities are currently under investigations. In this highly competitive international context, we propose within the ANR frame an original contribution to the area luminescent polyphenylpyridyl late transition metal complexes as emitters in optoelectronics in order to seek an innovative application in fine. Indeed, even though many functionalized phenylpyridyl and organic ancillary ligands were used, as far as we are aware, no example using organometallic ancillary ligands «OM-Ligands» was described. We indeed successfully introduced the novel concept of organometalloligands «OM-Ligands» in several phosphorescent polyphenylpyridyl Ru(II), Ir(III), Rh(III) and Pt(II) bimetallic assemblies. Several papers have already been published and prove the feasibility of our strategy. The so called organometalloligands are p complexes of benzoquinone and dithiobenzoquinone (ortho- and para-) stabilised by the «Cp*M» (M= Ir(I), Rh(I)) fragment. These organometalloligands are capable of binding through either the oxygen or the sulphur atoms to the chromophoric bricks to build phosphorescent polymetallic assemblies with real future applications in optoelectronic field. The preliminary results obtained by our group are highly stimulating and prove the strength of our proposal and exclude any major risk. In this context, we seek an ANR financial support to pursue our efforts in this competitive area in order to design and prepare luminescent coordination assemblies using our unique approach of the «OM-Ligands». We would like to draw attention to the fact, that last year, the ANR committee has examined the present proposal. The committee considered the project to be original, ambitious, on solid bases and well written. Moreover they considered the consortium to be of very high-level with internationally renowned partners in the fields of organometallic and coordination chemistry, photophysics and electrochemistry. In this revised version we modified our project to meet with the referees comments. For instance the size and pattern of the luminescent coordination polymers are governed by the self-assembly process. Further as requested by the referees, a fourth partner is now included in this revised version, the latter will contribute in harmony towards applicative objectives in the area of optoelectronics. In order to carry out these objectives, a support from the ANR is crucial for us in a highly competitive context.