Updated Spectrophotometric Investigation of Neodymium Complexes formed with 1-(2-Pyridylazo-2-Naphthal and 2-(5-Bromo-2-Pyridylazo)-5-Diethylamino-m-Phenol

Abstract

The updated investigation of neodymium complexes formed with two ligands: 1-(2-pyrdidylazo)-2-naphthol (PAN) (at pH 10) and 2-(5-bromo-2-pyridylazo)-5-diethylamino-m-phenol (5–Br–PADAP) (at pH 8) was made in detail by β-corection spectrophotometry.
The nonionic surfactant, emulsifier OP was found to increase the
sensitivity and solubility of ligand and complex. The characteristic
factors were calculated, for example, complex ratio and stability
constant. The results showed that Nd(PAN)₂ and Nd(5-Br-PADAP)₂
were formed in this study and their real but not apparent molar
absorptivities were the first to be determined as follows:
ε⁵⁵⁰_Nd(PAN)2 = 4.54 x 10⁴ at pH 10 and ε⁵⁶⁰_{Nd(5–Br–PADAP)2} = 8.4 X 10⁴ L
mol^–1 cm^–1 at pH 8. In addition, the cumulative stability constants
of two complexes Nd(PAN)₂ and Nd(5–Br–PADAP)₂ were still computed
to be 1.04 x 10¹⁰ and 4.73 x 10⁹ both in ionic strength 0.1
and at temperature 20ºC respectively