1,3-Dipolar cycloaddition between a metal–azide (Ph3PAuN3) and a metal–acetylide (Ph3PAuCCPh): an inorganic version of a click reaction

Abstract

This report describes the synthesis and characterization of 1,5-bis-triphenylphosphinegold(I) 1,2,3-triazolate (3_(1,5)). The synthesis of the dinuclear complex 3_(1,5) is achieved via an unprecedented inorganic click (iClick) reaction between the metal–azide PPh₃AuN₃ (1) and the metal–acetylide PPh₃Au–CCPh (2). Characterization of 3_(1,5) includes multinuclear NMR spectroscopy, combustion analysis, and single crystal X-ray crystallography. Experimental characterization is complemented with density-functional-theory (DFT) calculations which indicate the 1,4-isomer 3_(1,4) is less stable by 3.3 kcal mol⁻¹. The energetic difference lies primarily in the ability of the phenyl group in the 4-position of 3_(1,5) to lie coplanar with the triazolate to create a delocalized π-bonding HOMO orbital.