Comparative Study of Microwave Assisted and Conventional Synthesis of Tp*-Complexes

Hamed Aboajila Alqamoudy

doi:10.11648/j.jmpt.20180401.14

Abstract

Cobalt, copper and nickel complexes with tris(3,5-dimethyl-1H-pyrazol-1-yl)hydroborate (Tp*) were synthesized by the reaction of potassium tris(3,5-dimethyl-1H-pyrazol-1-yl)hydroborate (KTp*) with the corresponding metal(II) chloride by using conventional reflux methods and microwave methods. The two methods were compared and the microwave method was found to be less time consuming and gave higher yields.

Highlights

Pyrazole-derived ligands, known collectively as poly ligands, are derived from two or more Ndeprotonated pyrazole rings bound to a main group atom through one of the ring nitrogens [1]
We present a method for synthesizing complexes containing (KTp*) ligand and some transition metal atoms, (Tp*-Metal), using reflux methods and microwave techniques with a comparison between the two methods
Potassium tris(3,5dimethyl pyrazolyl) hydroborate (KTp*) was synthesized with the use of microwave according to the method described in a previous publication [21]. (Yield: 90 %); m.p: >380°C

Summary

Introduction

Pyrazole-derived ligands, known collectively as poly (pyrazolyl) ligands, are derived from two or more Ndeprotonated pyrazole rings bound to a main group atom through one of the ring nitrogens [1]. Tris(pyrazolyl) borate (Tpx) ligands, known as scorpionates, have attracted considerable attention and proven to be extremely popular ligands since their introduction by Trofimenko in 1967 [3,4] They constitute one of the most widely used group of ligands in chemistry. In a dedicated microwave reactor, reactions can be run in sealed vials under carefully controlled conditions at temperatures up to 200°C and pressures up to 20 bar This provides the means to heat reactions much higher than conventional open-vessel conditions, in which the maximum temperature is limited to the boiling point of the solvent. We present a method for synthesizing complexes containing (KTp*) ligand and some transition metal atoms, (Tp*-Metal), using reflux methods and microwave techniques with a comparison between the two methods

Chemicals and Materials

Instrumentations

Syntheses

Results and Discussion

IR Spectroscopy

Conclusion