title: Hydrotris(3-mesitylpyrazolyl)borato-copper(I) alkyne complexes: synthesis, structural characterization and rationalization of their activities as alkyne cyclopropenation catalysts.
abstract: The use of the bulky hydrotris(3-mesitylpyrazolyl)borate anionic ligand has allowed the synthesis of stable Tp(Ms)Cu(alkyne) complexes (alkyne = 1-hexyne, 1, phenylacetylene, 2, and ethyl propiolate, 3). The spectroscopic and structural features of these compounds and their relative reactivity have been examined, indicating the existence of a low π back-bonding from the copper(I) centre to the alkyne. Ligand exchange experiments have shown that terminal alkyne adducts are more stable than internal alkyne analogues. In good accordance with this, the previously reported alkyne cyclopropenation reaction catalysed by the Tp(x)Cu complexes can be rationalized and correlated with their relative stability.
authors.affiliation: Laboratorio de Catálisis Homogénea, Departamento de Química y Ciencia de los Materiales, Unidad Asociada al CSIC, Centro de Investigación en Química Sostenible (CIQSO), Universidad de Huelva, Campus de El Carmen, 21007 Huelva, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Martín
authors.forename: Marta
authors.initials: M
authors.lastname: Sierra
authors.forename: Eleuterio
authors.initials: E
authors.lastname: Alvarez
authors.forename: Tomás R
authors.initials: TR
authors.lastname: Belderrain
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Pérez