1,3-Dipolar cycloaddition between a metal–azide (Ph3PAuN3) and a metal–acetylide (Ph3PAuCCPh): 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 PPh(3)AuN(3) (1) and the metal-acetylide PPh(3)Au-C≡CPh (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.

Expanding iClick to group 9 metals

“…In 2010 [41], we published the cycloaddition reaction between a gold(I)-acetylide and a gold(I)-azide to from a triazolate linked digold complex (Fig. 1a); and termed the reaction inorganic click (iClick) to acknowledge the two metal ions that substitute either protons or organic substituents in typical copper-catalyzed azidealkyne cycloadditions (CuAAC) [42,43].…”

Azide Chemistry – An Inorganic Perspective, Part II[‡] [3+2]‐Cycloaddition Reactions of Metal Azides and Related Systems

“…[492] To conclude this short chapter, we refer to the blockbuster already exposed in the Introduction: the perfect inorganic version of the click reaction between Ph 3 PAuN 3 and PhCϵCAuPPh 3 as performed in the group of Veige (Equation (22)). [20] In extension of this remarkable inorganic "click" (iclick), Veige and co-workers studied the reactions of the diazido complexes cis-[Pt(N 3 ) 2 (PR 1 3 ) 2 ] (R 1 = Et, Ph) with the gold acetylide (Equation (23)). [493] A particularly interesting product resulting from the reaction of (25)).…”

“…Nothing illustrates this better than the following equation denoting "iClick", the first inorganic version of a 1,3-dipolar Huisgen cycloaddition reaction, which perfectly fits into the concept of this article, besides. [20,21] In no time an enormous number of reviews, tutorial reviews and cover stories came out on this and related subjects, which, though only marginally relevant to the current issue, will shortly be referred to in chapters 1 and 3 of this review, or where it appears appropriate.…”

“…[26,27] Starting in the mid-1960s, a series of papers mainly coming from our Munich laboratory not only brought numerous new compounds into play, but also showed the azide ligand to be a centre of remarkable reactivity with a wide range of synthetic applications. [28][29][30][31][32][33][34][35][36][37] In a sense, this was the rise of what had recently been referred to as "the Inorganic Version of the Huisgen 1,3-Dipolar Cycloaddition", [20,21,38] exactly the subject of the present survey. At about the same time, similar studies had been carried out by Dori and Ziolo, [39,40] and there were sporadic reports before and thereafter.…”

Synthesis, characterization, photophysics, and anion binding properties of gold(i) acetylide complexes with amide groups

“…The Au(1)-C(1) and Au(1)-P(1) bond distances for 3a (2.012(5) and 2.2802(18) Å, respectively) are similar to those reported for other gold(I) arylacetylide complexes with triphenylphosphine ligands. 55,56 The CRC bond distance (1.187(8) Å) is in the range of those typical for gold(I) Scheme 1 Synthetic route for gold(I) acetylide complexes 3a-3d. (i) Pd(PPh 3 ) 2 Cl 2 , CuI, (CH 3 ) 3 Si-CRCH, NEt 3 , reflux, N 2 , overnight; (ii) ClC(O)C 6 H 4 -R, NEt 3 , CHCl 3 , reflux, N 2 , overnight; (iii) Ph 3 PAuCl, KFÁ2H 2 O, CH 2 Cl 2 /CH 3 OH, dark.…”