Within this theme, we are interested in the reactivity of lamellar matrices containing (Qn)2- oligomers (Q = S, Se; n = 2-4) towards a metal. The reactivity of the precursor La2O2S2 perfectly sums up our research theme. This compound, built from 2/∞[La2O2]2+ sheets separated by free (S2)2- pairs, can intercalate Cu at low temperatures to lead to the compound La2O2Cu2S2. During this reaction, the sulfur pair (S2)2- is reduced by copper according to the reaction (S2)2- + 2 Cu° → 2 S2- + 2 Cu+. This reaction is reversible, as Cu atoms can be deinserted from La2O2Cu2S2 at 200°C with I2 as the oxidizing agent. We have shown that similar reactions can be obtained using other polychalcogenides (BaS3, LaSe2 …) or other transition elements (Fe, Co, Ni) with systematically a strong correlation between host and intercalated crystal structures (topochemical reactions). We are currently exploring reactivity with alkali metals, and our initial results point to totally different behaviours, with stabilization of metastable structures.
Find out more at[Chalcogen Dimers],[Oligomers].
People involved: I. Braems, M. T. Caldes, L. Cario, B. Corraze, C. Guillot-Deudon, E. Janod, S. Jobic.
Keywords: topochemical reaction, hole chemistry, chalcogenides, oligomers, exploratory chemistry
This research is conducted within the “Chalcogenide” transverse axis built around IMN’s MIOPS, PMN and ID2M groups. Our studies have led to collaborations with G. Frapper of the Institut de Chimie des Milieux et Matériaux in Poitiers, and Gwladys Steciuk and Lukáš Palatinus of the Institute of Physics in Pragues.
We are participating in the Core to Core project with Japan (resp. Pr. Kageyama), bringing together internationally renowned laboratories from the universities of Kyoto, Oxford, Antwerp, Shenzhen, Bordeaux, Lille and Rennes.
