Effect of the [2-(diphenylphosphorylmethoxy)phenyl]diphenylphosphine oxide derivative structures on the extraction and ion-selective properties toward rare-earth elements

The effect of structures of the derivatives of [2-(diphenylphosphorylmethoxy)phenyl]-diphenylphosphine oxide (L1) on the complexation properties toward rare-earth elements (REE) was studied. A new structural analogue of L1, isopropyl 2-(diphenylphosphorylmethoxy)benzoate (L3), was synthesized. The extraction of REE by the carboxylated podand L3 in a 1,1,7-trihydrododecafluoroheptanol—water system with the HNO3 concentration varied in a range from 1 to 6 mol L−1 was studied. The stability constants of the neodymium(iii) and erbium(iii) nitrate complexes with L3 and 1-(methoxydiphenylphosphoryl)-2-diphenylphosphoryl-4-ethylbenzene (L2) and of lutetium(iii) nitrate and chloride complexes with L2 in 1,1,7-trihydrododecafluorheptanol were determined. The properties of the membranes of the ion-selective electrodes based on L1, L2, and L3 toward REE cations were tested. The crystal structures of L3 and [NdL3(NO3)3(DMSO)2] were determined by X-ray diffraction analysis.