Ruthenium Hydride Complex Supported on Gold Nanoparticle Cored Triazine Dendrimers for C–C Coupling Reactions

Abstract

In this work, the unusual ability of a ruthenium hydride catalyst, [RuHCl(PPh 3 ) 3 CO], supported on gold nanoparticle cored triazine dendrimers in the Suzuki−Miyaura cross-coupling reaction and also in the synthesis of diaryl ketones is reported. [Ru-H@AuNPs-TD] was characterized by Fourier transform infrared spectroscopy, CHNS, TEM, SEM, ICP, and TGA analyses. The ruthenium hydride catalyst was used as a heterogeneous catalyst for the C−C coupling reactions of aryl halides with phenylboronic acids, and the biphenyl derivatives were produced in good to excellent yields. On the other hand, this catalytic system was applied for synthesis of diaryl ketones by the reaction of phenylboronic acids with substituted benzaldehydes. Moreover, this catalyst can be well-dispersed in the reaction medium, conveniently separated from the reaction mixture, and reused several times without significant loss of its activity.

Supported ruthenium hydride catalysts for direct conversion of alcohols to carboxylic acids using styrene oxide as oxidant

“…After successful application of these two catalysts in organic synthesis we decided to investigate their catalytic activity in the direct synthesis of carboxylic acids from alcohols. In this manner, first the reaction parameters were optimized in the oxidation of benzyl alcohol with styrene oxide (Table ).…”

“…Comparison of the catalytic activity of these two catalysts shows that the [Ru–H@AuNPs–TD] is more reactive than [Ru–H@EDT–MWCNT] in the direct oxidation of alcohols to carboxylic acids with styrene oxide. This can be attributed to the smaller size of the gold nanoparticles compared to MWCNTs …”

“…The Ru content of the catalyst was determined by a Jarrell–Ash 1100 ICP analysis. The [RuHCl(CO)(PPh 3 ) 3 ] complex was prepared and supported on MWCNT and gold nanoparticles according to the literature . The procedure for catalysts preparations are supplied in supporting information.…”

“…But the main disadvantage of this expensive catalyst is that the catalyst is not recoverable and reusable. One way to solve this problem is to immobilized this homogeneous catalyst on solid supports such as carbon nanotubes and gold nanoparticles …”

Nano–silica functionalized with thiol–based dendrimer as a host for gold nanoparticles: An efficient and reusable catalyst for chemoselective oxidation of alcohols

“…Recently, some applications of dendritic materials in organic syntheses have been reported by our research group . By combination the advantages of gold nanoparticles as catalyst in the oxidation of alcohols and the ability of dendrimers in the stabilization of nanoparticles, here we wish to present an efficient and environmentally friendly method for preparation of gold nanoparticles immobilized on nano–silica functionalized thiolated dendritic polymer (Au np –nSTDP).…”