A green route for the cross-coupling of azide anions with aryl halides under both base and ligand-free conditions: exceptional performance of a Cu2O-CuO-Cu-C nanocomposite.

Morteza Karimzadeh,Dariush Tarokh,Khodabakhsh Niknam,Neda Manouchehri

doi:10.1039/c8ra04608e

Abstract

A convenient, inexpensive and effective route for the preparation of a Cu2O–CuO–Cu–C nanocomposite is described here by applying Cu(ii) as a source of copper. Characterization of the nanocomposite was performed with X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDX). Analysis of the data showed that the particles of the nanocomposite are uniformly distributed and show high catalytic activity in the cross-coupling of sodium azide with various aryl iodides and bromides. This nanocomposite has a high level of performance, and even led to the synthesis of the products at room temperature. In addition, this is the first report of the synthesis of aryl azides under both base- and ligand-free conditions. For the first time, both ligand- and base-free conditions were applied for the synthesis of aryl azides, which implies exceptional performance of the Cu2O–CuO–Cu–C nanocomposite. Simultaneous removal of the base and ligand in a green solvent is the main advantage of this reaction. Unfortunately, aryl bromides and aryl iodides with electron-withdrawing functional groups in their scaffold did not give the desired aryl azides.

Highlights

Aryl azides are extensively used in bioactive molecules as synthetic motifs due to their wide range of usages.[1,2,3] These compounds contain special functional groups with the capability to get involved in the formation of nitrenes and insert different heteroatoms
The crystal structure of the copper-based nanocomposite was studied by X-ray diffraction (XRD) analysis (Fig. 2)
The amount of carbolite phase in the nanocomposite is negligible when the height of this peak is compared to the others, indicating that a very small amount of C is present in the nanocomposite.[30,31]

Summary

Introduction

Aryl azides are extensively used in bioactive molecules as synthetic motifs due to their wide range of usages.[1,2,3] These compounds contain special functional groups with the capability to get involved in the formation of nitrenes and insert different heteroatoms. Their affectivity as optical sensors has already been described.[4] These compounds have bene cial effects in photography,[5] dendrimers with conducting capability[6] and light-rendered energizing polymers.[7] obtaining an effective route to produce such compounds is highly desirable.

Methods

Results

Conclusion