| dc.description | Complexes of vanadium(IV) with aminopolycarboxylic acids, nitrilotriacetic (NTA), nitrilodiaceticpropionic
(NDAP), nitrilodipropionicacetic (NDPA), and nitrilotripropionic (NTP)
acids were studied by electromotrice force measurements [emf(H)] in 3.0M KCl ionic medium
at 25 C. Data analysis using the least-squares program LETAGROP, according to the general
reaction p Hþþq VO2þþr C3
!Hp(VO)qCr
pþ2q 3r, indicates that the following complexes
are formed (H3C ligands): NTA ([VOC] and [OHVOC]2 ); NDAP ([VOC] and [OHVOC]2 );
NDPA ([VOC] and [OHVOC]2 ); and NTP ([H2VOC]þ, HVOC, [VOC] , and [OHVOC]2 ).
The following order of coordination capacity NTA4NDAP4NDPA4NTP is suggested,
based on values of stability constants and is attributed to the increase in propionic groups in the
sequence. The study confirms that five-membered ring chelates are the most stable for VIV, like
CuII, NiII, lanthanides, and other heavier elements. | |
