Coordination compounds of diethyl (5-ethyl-2-hydroxyphenyl)phosphonate with lithium, sodium and potassium. Synthesis, single-crystal X-ray diffraction analysis and FTIR spectroscopic study

Dialkyl (5-ethyl-2-hydroxyphenyl)phosphonates are of O-donor ligands and have received considerable attention as a potential extractants for the selective extraction of lithium in the presence of large excesses of sodium and potassium ions. As part of the study of the relationship between the structure of the extractant and the ability to selectively bind lithium ions, the crystal structure of diethyl (5-ethyl-2-hydroxyphenyl)phosphonate HL_Et was established by X-ray diffraction for the first time. HL_Et coordination compounds with lithium, sodium, and potassium were synthesized for the first time; their composition and structure were established by elemental analysis, single-crystal X-ray diffraction analysis, and FTIR spectroscopy. Based on the obtained results, structural regularities of binding of dialkyl (5-ethyl-2-hydroxyphenyl)phosphonates with lithium, sodium and potassium cations were established for the first time. The ability of dialkyl (5-ethyl-2-hydroxyphenyl)phosphonates to form six-membered metallocycles with cations of alkali metals was confirmed.