title: An ab Initio Benchmark and DFT Validation Study on Gold(I)-Catalyzed Hydroamination of Alkynes.
abstract: High level ab initio calculations have been carried out on an archetypal gold(I)-catalyzed reaction: hydroamination of ethyne. We studied up to 12 structures of possible gold(I)-coordinated species modeling different intermediates potentially present in a catalytic cycle for the addition of a protic nucleophile to an alkyne. The benchmark is used to evaluate the performances of some popular density functionals for describing geometries and relative energies of stationary points along the reaction profile. Most functionals (including hybrid or meta-hybrid) give accurate structures but large nonsystematic errors (4-12 kcal/mol) along the reaction energy profile. The double hybrid functional B2PLYP outperforms all considered functionals and compares very nicely with our reference ab initio benchmark energies. Moreover, we present an assessment of the accuracy of commonly used approaches to include relativistic effects, such as relativistic effective potentials and a scalar ZORA Hamiltonian, by a comparison with the results obtained using a relativistic all-electron four-component Dirac-Kohn-Sham method. The contribution of nonscalar relativistic effects in gold(I)-catalyzed reactions, as we investigated here, is expected to be on the order of 1 kcal/mol.
authors.affiliation: Istituto di Scienze e Tecnologie Molecolari del CNR c/o Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , 06123, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ciancaleoni
authors.affiliation: Istituto di Scienze e Tecnologie Molecolari del CNR c/o Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , 06123, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Rampino
authors.affiliation: Dipartimento di Chimica, Fisica e Ambiente, Università di Udine , Via Cotonificio 108, I-33100 Udine, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Zuccaccia
authors.affiliation: Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , 06123, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Tarantelli
authors.affiliation: Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , 06123, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Belanzoni
authors.affiliation: Istituto di Scienze e Tecnologie Molecolari del CNR c/o Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , 06123, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Belpassi