Dinuclear Copper(II) 3,4,5-Tri-O-benzylgallate



Masahiro Mikuriya1, *, Chihiro Yamakawa1, Naoyuki Masuda1, Daisuke Yoshioka1, Sayuri Yamaguchi2, Hidetoshi Yamada2, Tsutomu Mizuta3, Naomi Kawata4, Hidekazu Tanaka5, Makoto Handa5
1 Department of Applied Chemistry for Environment and Research Center for Coordination Molecule-based Devices, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan
2 Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan
3 Department of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526, Japan
4 Natural Science Center for Basic Research and Development, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526, Japan
5 Department of Chemistry, Interdisciplinary Graduate School of Science and Engineering, Shimane University, 1060 Nishikawatsu, Matsue 690-8504, Japan

Abstract

Background:

Ellagitannins have attracted much attention because of the biological and pharmacological activities. In the total synthesis of ellagitannins, 3,4,5-tri-O-benzylgallic acid has been a key compound to introduce the protected galloyl group. From the perspective of coordination chemis-try, 3,4,5-tri-O-benzylgallic acid is an interesting carboxylate ligand which might be capable of dinucle-ar carboxylate complex. Such a dinuclear carboxylate complex might be interesting as a new example of copper acetate type complexes.

Objectives:

The objective of the work is to synthesize a copper acetate type complex by using 3,4,5-tri-O-benzylgallic acid and to see a new feature of copper acetate compounds, by elucidating the crystal structure, magnetic property, and adsorption property for N2 gas.

Methods:

Copper(II) 3,4,5-tri-O-benzylgallate has been synthesized by a reaction of 3,4,5-tri-O-benzylgallic acid and copper(II) nitrate at pH=9 condition. The isolated complex was characterized us-ing single-crystal X-ray structure analysis, XRD analysis, UV-visible spectroscopy, IR spectroscopy, and temperature dependence of magnetic susceptibility.

Results:

The crystal structure shows a crystallographically centrosymmetric dinuclear molecule with four carboxylato-bridges and axial dimethylformamide molecules and crystal dmf molecules [Cu···Cu 2.6345(12) Å]. In the crystal, 1D supramolecular assembly by π-π interaction between the benzyl aro-matic rings of dinuclear molecules was observed. Temperature dependence of magnetic susceptibilities showed a considerable antiferromagnetic interaction between the two copper(II) ions (2J = –214 cm–1). Type-II gas-adsorption property was observed for N2.

Conclusion:

A key-compound for the total synthesis of ellagitannins, 3,4,5-tri-O-benzylgallic acid (Htbng), was shown to be a new ligand for the synthesis of dinuclear copper acetate analogue with a lantern-type core, extending the realm of copper acetate clusters.

Keywords: Copper acetate, Crystal structure, Magnetic property, 3,4,5-Tri-O-benzylgallic Acid.


Abstract Information


Identifiers and Pagination:

Year: 2019
Volume: 06
Publisher Item Identifier: EA-CHEM-2019-HT1-621-3

Article History:

Received Date: 15/1/2018
Revision Received Date: 27/3/2018
Acceptance Date: 27/1/2019
Electronic publication date: 20/2/2019
Collection year: 2019

© 2019 Mikuriya et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Correspondence: Address correspondence to this author at the Department of Applied Chemistry for Environment, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, 669-1337, Japan; Tel: +81-79-565-8365; Fax: +81-79-565-9729; E-mail: junpei@kwansei.ac.jp