Galactopyranoside-SubstitutedN-Heterocyclic Carbene Gold(I) Complexes: Synthesis, Stability, and Catalytic Applications to Alkyne Hydration

Abstract

A series of novel gold(I) complexes bearing galactopyranoside-based N -heterocyclic carbene ligands have been synthesized via transmetalation of the corresponding Ag(I) complex. Gold(I) complexes have been characterized by NMR, Fourier transform infrared (FTIR), and elemental analysis. An exhaustive NMR analysis shows that the complexes are not stable when hydroxyl groups are deprotected. Catalytic studies, using the alkyne hydration as a model reaction, indicate that the synthesized complexes are active and reusable.

Carbohydrate-based N-heterocyclic carbene-metal complexes: a new avenue for sustainable catalysts in organic transformations

“…The catalytic activity of synthesized complexes was applied in an alkyne hydration reaction, as in Scheme 32a and b. 59 All CNHC-Au(I) complexes 90a-d, 91 and their respective imidazolium salts were investigated as a catalyst in the hydration reaction in the presence of H 2 O, MeOH, and H 2 O/MeOH mixtures in the solvent system in Scheme 32a. Initially, for the reaction conditions, the authors decided to use 1 mol% of all catalyst 90aÀd, 91 and respective imidazolium salts at 100 1C in an aqueous solvent system up to 20 h. Therefore, no product formation was observed as in Table 5.…”

“…Scheme 32 (a) Preliminary investigation of the hydration reaction using CNHC-Au(I) complexes. 59 (b) Hydration of phenylacetylene catalyzed by 90a-d and 91 under optimal conditions. 59…”

“…Scheme 33 Investigation of the chemoselectivity of 90b in MeOH. 59 Scheme 34 (a) Synthesis of various imidazolium and imidazolinium salts via coupling reactions with thiosugars. 60 (b) Synthesis of CNHC Ag(I)thioglycosides via the ball mill method.…”

A new candidate for smart drug synthesis via silver (I)-NHC complexes

“…2) Among these compounds, compound 3a showed the best performance against both gram-positive and gram-negative bacteria [34]. The structures of whole synthesized NHC complexes were examined with spectroscopic techniques such as 1 H-NMR, 13 C-NMR [35] conductivity analysis [36], FT-IR spectra [37],…”

A new candidate of smart drug synthesis via silver (I)-NHC complexes

“…Among these compounds, compound 3a showed the best performance against both gram-positive and gram-negative bacteria [34]. The structures of all synthesized NHC complexes were examined with spectroscopic techniques such as 1 H-NMR, 13 C-NMR [35], conductivity analysis [36], FT-IR spectra [37], elemental analysis [38], LC-Mass spectra [39], UV-vis spectra [40], TGA-DTA analysis [41] and XRD spectra [42]. Activity tests for Ag(I)-NHC complexes against grampositive and gram-negative bacteria and fungi were performed.…”