%0 Journal Article 
%A García Algarra, Andrés
%A Pino-Chamorro, Jose Ángel
%A A. Laricheva, Yuliya
%A Guillamón, Eva
%A Fernández-Trujillo Rey, María Jesús
%A Bustelo, Emilio
%A L. Gushchin, Artem
%A Y. Shmelev, Nikita
%A A. Abramov, Pavel
%A N. Sokolov, Maxim
%A Llusar, Rosa
%A García Basallote, Manuel
%T Cycloaddition of alkynes to diimino Mo3S4 cubane-type clusters: a combined experimental and theoretical approach
%D 2016
%U http://hdl.handle.net/10498/20490
%X A heterocyclic ligand 4,40-di-tert-butyl-2,20-bipyridine (dbbpy) has been coordinated to the Mo3S4 cluster unit affording the complex [Mo3S4Cl3(dbbpy)3]+ ([1]+) in a one-step ligand-exchange protocol from [Mo3S4(tu)8(H2O)]Cl4 4H2O (tu = thiourea). The new cluster was isolated as [1]PF6 and [1]Cl salts in high yields and the crystal structure of the latter determined by X-ray analysis. The synthetic procedure was extended to tungsten to afford [W3S4Cl3(dbbpy)3]+ ([2]+). Kinetic and NMR studies show that [1]+ reacts with several alkynes to form dithiolene species via concerted [3+2] cycloaddition reactions whereas [2]+ remains inert under similar conditions. The different rates for the reactions of [1]+ are rationalised by computational (DFT) calculations, which show that the more electron-withdrawing the substituents of the alkyne the faster the reaction. The inertness of [2]+ is due to the endergonicity of its reactions, which feature DGr values systematically 5–7 kcal mol 1 more positive than for those of [1]+.
%~ Universidad de Cádiz