Synthesis and Catalytic Application of Two Mononuclear Complexes Bearing Diethylenetriamine Derivative Ligand.

Chao Liu,Yu-Cai Zhao,Zhao Yang,Hao Guo

doi:10.3390/molecules25092101

Abstract

Two mononuclear zero-dimensional Ni(II) and Zn(II) complexes bearing diethylenetriamine derivative ligand, namely [NiL(CH3COO)2(H2O)] (1) and [ZnL(CH3COO)2] (2) [L = N, N’-bis(2-hydroxybenzyl)diethylenetriamine], were synthesized under reflux conditions. The molecular composition and structure of the complexes were identified by IR, PXRD, elemental analyses, and single crystal X-ray diffraction. Complex 1 belongs to a monoclinic crystal system with the P21/n space group, and Complex 2 belongs to a monoclinic crystal system with the C2/c space group. The Henry reaction of nitromethane with aromatic aldehydes was explored with Complexes 1 and 2 as the catalyst. Results from the catalytic reaction revealed that the complexes displayed excellent catalytic activities under the optimized conditions and that the substrate scope of aromatic aldehydes could be extended to a certain extent. In addition, the possible catalytic mechanism of the Henry reaction was also deduced.

Highlights

Due to their special structures with difunctional group, β-nitroalcohols are very important and valuable chemical intermediates [1,2], which can be used in the synthesis of various biologically active derivatives, including amino alcohols [3], nitroalkenes [4], nitroketones, and so on [5,6]
Inspired by the promising applications in the field of organic synthesis, we investigated the Inspired by the applications in the of organic synthesis, investigated the catalytic activities of promising the synthesized complexes in field the Henry reaction
The asymmetric unit of Complex 1 consisted of two acetate anions, one ligand, one water molecule, and one Ni(II) cation

Summary

Introduction

Due to their special structures with difunctional group, β-nitroalcohols are very important and valuable chemical intermediates [1,2], which can be used in the synthesis of various biologically active derivatives, including amino alcohols [3], nitroalkenes [4], nitroketones, and so on [5,6]. The most common method of synthesizing β-nitroalcohols is the nucleophilic addition reaction of nitroalkane with the carbonyl compounds in the presence of catalysts, such as organic small molecules [7,8], ionic liquids [9,10], and metal complexes [11,12]. Interest in the area of rare earth metal-based catalysts has been enhanced considerably, and a variety of rare earth metal complexes has been reported to promote the Henry reaction with good catalytic activities [17]. Ni(II) and Zn(II) complexes, two kinds of typical transition metal complexes, have attracted considerable attention due to their encouraging characteristics and broad application prospects for organic synthesis as catalysts [18,19,20,21]. The research on and exploration of their catalytic activities in the Henry reaction have been a hotspot [22,23,24]

Methods

Discussion

Conclusion