Synthesis and Complexation Properties of 2-Hydroxy-5-methoxyphenylphosphonic Acid (H3L1). Crystal Structure of the [Cu(H2L1)2(\u041d2\u041e)2] Complex

G S Tsebrikova,L I Demina,V E Baulin,V P Soloviev,Yu I Rogacheva,I S Ivanova,A Yu Tsivadze,A B Ilyukhin

doi:10.1134/s1070363221110074

Abstract

2-Hydroxy-5-methoxyphenylphosphonic acid (H3L1) and the complex [Cu(H2L1)2(H2O)2] were synthesized and characterized by IR spectroscopy, thermogravimetry, and X-ray diffraction analysis. The polyhedron of the copper atom is an axially elongated square bipyramid with oxygen atoms of phenolic and of monodeprotonated phosphonic groups at the base and oxygen atoms of water molecules at the vertices. The protonation constants of the H3L1 acid and the stability constants of its Cu2+ complexes in water were determined by potentiometric titration. The protonation constants of the acid in water are significantly influenced by the intramolecular hydrogen bond and the methoxy group. The H3L1 acid forms complexes CuL‒ and CuL24‒ with Cu2+ in water.

Highlights

Organophosphorus compounds are used in many fields of medicine and agriculture and play a significant role in organic synthesis, catalysis, and biochemistry [1,2,3,4,5,6]
In the synthesis of H3L3) (6.19±0.12 (H3L1) acid (Scheme 2), we used the technique, which we developed earlier [14]
Cu + L = CuL Cu + 2L = CuL2 Cu + L + OH = Cu(OH)L Cu + 2L + OH = Cu(OH)L2 log βi ± sd Stability constants of copper(II) complexes with deprotonated forms of H3L1 acid were determined by the potentiometry method using the CHEMEQUI program (Table 4)

Summary

Introduction

Organophosphorus compounds are used in many fields of medicine and agriculture and play a significant role in organic synthesis, catalysis, and biochemistry [1,2,3,4,5,6]. The protonation constants of H3L1 acid and the stability constants of its complexes with Cu2+ in water were determined; the IR spectroscopy and thermogravimetry data are presented.

Results

Conclusion