Gold nanoparticle (AuNPs) and gold nanopore (AuNPore) catalysts in organic synthesis

Abstract

Organic synthesis using gold has gained tremendous attention in last few years, especially heterogeneous gold catalysis based on gold nanoparticles has made its place in almost all organic reactions, because of the robust and green nature of gold catalysts. In this context, gold nanopore (AuNPore) with a 3D metal framework is giving a new dimension to heterogeneous gold catalysts. Interestingly, AuNPore chemistry is proving better than gold nanoparticles based chemistry. In this review, along with recent advances, major discoveries in heterogeneous gold catalysis are discussed.

Nanoporous Metals as Novel Catalysts for Chemical Transformations☆

“…A number of methods have been tried to selectively reduce C]O bond, especially, using metal and hydrogen gas as a reducing source. 55 However, in most of the cases, it is difficult to achieve chemoselective reduction of a, b-unsaturated aldehydes to allylic alcohols. Some of the metals such as Pt or Au possess special affinity for C]O and show high selectivity for C]O reduction.…”

Organic Synthesis Catalyzed by Supported Gold Nanoparticles

“…from Au-based alloy. 19,37 It is interesting to note that, even without the presence of an oxide support, nanoporous gold still displays very high activity for CO oxidation, even at À30 C, which really challenges the proposed mechanism for gold catalyzing CO oxidation. 39 However, recent works reveal that residues of the secondary metallic species play an important role for the catalytic performance.…”

“…18,34,35 Besides supported metallic gold catalysts, two kinds of unsupported nanogold catalysts should also be mentioned due to their unique physiochemical properties and catalytic performance. One is nanoclusters composed of several or dozens of gold(0) atoms, 36 and another is unsupported nanoporous gold, 19,37 which possesses a three-dimensional open porous framework. A very high atomic efficiency can be obtained by using the nanocluster, which is even higher than analogous enzymatic catalysts.…”

“…[7][8][9][10] Such processes have been thoroughly reviewed over the past few years. [11][12][13][14][15][16][17][18][19] Another pioneering work, the gold-catalyzed hydrochlorination, has triggered abundant studies in homogeneous gold catalysis. In the last few decades, great achievements have been obtained by using coordinated Au(III) or Au(I) with well-designed ligands for alkyne additions and functionalization.…”

Reduction of quinolines to 1,2,3,4-tetrahydroquinolines with hydrosilanes/ethanol catalyzed by TiO2-supported gold nanoparticles under solvent free conditions

“…Heterogeneous reductive processes catalyzed by supported gold nanoparticles (Au NPs) [1][2][3][4][5] and nanoporous gold 6 have received considerable attention especially over the past decade. The reductants employed are H 2 (direct hydrogenation) and CO/H 2 , formates, alcohols, hydrosilanes or hydroborane (transfer hydrogenation).…”