Abstract
At the ambient temperature and under catalyst-free conditions, reactions between [MN3(LET)]PF6 (M = Pd(II) and Pt(II); LET = 2,6-bis(1-ethylbenzimidazol-2 '-yl)pyridine) and substituted alkynes (dimethyl acetylene-dicarboxylate and 4,4,4-trifluoro-2-butynoic acid ethyl ester) afforded the corresponding triazolate complexes. These reactions produced a mixture of triazolate bound isomers. The N1 triazolate isomer of the Pt(II) complexes, which first appeared in the [3 + 2] coupling, eventually isomerized to the N2-analogue during the incubation in DMSO. The reactions of [MN3(LET)]PF6 with asymmetric alkyne, 4,4,4-trifluoro-2-butynoic acid ethyl ester, produced a mixture of the three anticipated triazolate isomers, according to 19F NMR spectroscopy. The stability of the triazolate complexes was investigated, along with the cycloaddition reaction's mechanism and the nature of the intermediates, using NMR spectroscopy.