Phosphorescent complexes of {Mo<inf>6</inf>I<inf>8</inf>}⁴⁺with triazolates: [2+3] cycloaddition of alkynes to [Mo<inf>6</inf>I<inf>8</inf>(N<inf>3</inf>)<inf>6</inf>]^2-

Abstract

© The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. (Bu4N)2[Mo6I8(N3)6], prepared in a clean high-yield reaction from (Bu4N)2[Mo6I8(CH3COO)6] and Me3SiN3, undergoes [3+2] cycloaddition with CH3O(O)CC(O)OCH3 with the formation of a novel hexakis(triazolate) complex, (Bu4N)2[Mo6I8(N3C2(COOCH3)2)6] with symmetrically coordinated 4,5-di(carbmethoxy)triazol-2-yl ligands. The product was characterized by X-ray analysis, NMR, IR and ESI-mass spectrometry. It undergoes a quasi reversible oxidation in CH3CN at E1/2 = 1.36 V (vs. Ag/AgCl) and is red-light emissive upon UV photoexcitation. Reaction with methylpropiolate also yields a corresponding hexakis(triazolate) complex, [Mo6I8(N3C2H(COOCH3))6]2-, which exists as a 1:1 mixture of two isomers. Alkynes that lacking strongly electron-withdrawing substituents fail to undergo the cycloaddition reaction. This journal is