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RUTHENIUM AND OSMIUM CLUSTER COMPLEXES DERIVED FROM N-HETEROCYCLIC SILYLENES, GERMYLENES AND STANNYLENES

Final Report Summary - POLYRUOSSIGESNYLENES (RUTHENIUM AND OSMIUM CLUSTER COMPLEXES DERIVED FROM N-HETEROCYCLIC SILYLENES, GERMYLENES AND STANNYLENES)

PROJECT OBJECTIVES

-The purpose of POLYRUOSSIGESNYLENES was to extend the chemistry of ruthenium and osmium clusters to derivatives containing group-14 bis(amino)metalenes (NHM, M = Si, Ge, Sn). The objectives were: (1) To prepare the first ruthenium and osmium clusters containing NHMs; (2) To study the reactivity of the prepared clusters; (3) To rationalize some of the obtained results with the help of theoretical calculations; and (4) To evaluate of the catalytic activity of the synthesised clusters.

WORK PERFORMED SINCE THE BEGINNING OF THE PROJECT

-The research activity included the preparation of cyclic group-14 bis(amino)metalenes and also of donor-stabilized NHMs and non-cyclic bis(amino)metalenes and the study of their reactivity with ruthenium and osmium clusters (other transition metal complexes, such as Fe, Co, Mn, Re, and Au were also tested). DFT calculations were performed to rationalize some of the obtained results, particularly, the uncommon coordination of certain amidinate-type donor-stabilized NHMs (M = Si, Ge) to polymetallic complexes. Eventually, the catalytic activity of the least air-sensitive complexes containing ligands with potential hemilabile character (particularly, mixed Ru2Ge and Co2Ge clusters), was tested in organic processes of interest, such as the Pauson-Khand cyclization and alcohol dehydrogenations.

MAIN RESULTS

-The main results published were: (I) Syntheses and reactivity of the first transition metal carbonyl clusters derived from NHMs: This work unveiled that the volume of the NHM bis(amino)metalene ligands is of key importance in determining the nature of the final products of their reactions with [Ru3(CO)12] (Inorganic Chemistry, 2011, 50, 6195; 2012, 51, 2569); (II) Expansion of the noncarbene-like coordination chemistry of NHMs: This work revealed an unprecedented transformation of a monodentate donor-stabilized NHM (M = Ge) into a bidentate Ge,N-ligand. Such a new ligand allowed the isolation of ruthenium and cobalt clusters that, in contrast to the vast majority of NHM complexes, were air stable (Dalton Transactions, 2012, 42, 1329); (III) First systematic reactivity studies on an NHM-ruthenium cluster: This work revealed the reactive sites of this type of complexes and their capacity to activate inorganic sigma bonds under mild conditions (unpublished results); (IV) Introduction of bis(amino)metalenes as ligands in gold chemistry: This study led to chlorometalate-metalene gold complexes that can be easily functionalized by chloride replacement (Inorganic Chemistry, 2012, 51, 3896); (V) Synthesis of the first heavier carbene analogues stabilized by an amidate fragment: Considering the ease of preparation and great variety of modifications allowed by simple amides, this work represented the starting point of a new generation of ligands for transition metal complexes (Organometallics, 2013, 32, 3557); (VI) Synthesis of the first Mn, Re, and Co carbonyl complexes derived from donor-stabilized bis(amino)metalenes and initial studies on their reactivity.

IMPACT OF THE PROJECT

-The impact of the project can be measured considering: (A) The complete reintegration of the fellow who, thanks to the improvement of his track record and capacity as independent researcher during the ERG project, has recently obtained a “Ramón y Cajal” grant sponsored by the Spanish Government (5-year contract, position as professional researcher ensured after this period and €40k for contracting personnel and/or buying consumables); (B) The recognition from the scientific community (acceptance for publication of the results submitted so far and invitation to write a review on his research area in Coordination Chemistry Reviews); (C) Training of PhD students (two during the ERG project and others that will be sponsored by the “Ramón y Cajal” grant); (D) The opening, inspired by the ERG project, of a cut-edge research line (multifunctional heavier carbene analogues). As a proof of quality, the application of an ERC Starting Grant (FP7-336861) in this new area passed the first evaluation stage (only 10 % of the applications go this far).

CONCLUSION

The main objective of the “Reintegration Grant” has been achieved because the fellow has now got a long-term employment in research and has established his own research group. Other beneficiaries of this proyects are (a) the PhD students that, thanks to the this project and its budgetary support, have received high quality training, (b) the Spanish research system, that has seen increased the number of its high-quality researches, and (c) the international scientific community, who has in hand the results provided by this project and will receive those afforded in the future by the fellow’s research group.