Structural Role of Isonicotinic Acid in U(VI), Np(VI), and Pu(VI) Complexes with TcO₄^–, ReO₄^–, and ClO₄^– Ions

Abstract

A series of new pertechnetate, perrhenate, and perchlorate compounds of hexavalent U, Np, and Pu containing isonicotinic acid were synthesized. Their crystal structures were determined by X-ray diffractometry. In all compounds, actinide atoms are found in pentagonal bipyramidal surroundings. They are coordinated by 2 to 4 isonicotinic acid molecules which exist in zwitterionic form as a result of N atom protonation. If only 2 or 3 isonicotinic acid molecules are present in the surroundings of an actinide (An) atom, TcO or ReO anions act as monodentate ligands. Otherwise, XO play the role of outer sphere anions. Electron and IR spectra of the compounds correlate with their crystal structure.

Stepwise ortho Chlorination of Carboxyl Groups for Promoting Structure Variance of Heterometallic Uranyl–Silver Coordination Polymers of Isonicotinate

“…The isonicotinate skeleton is used as an organic linker here on account of its bearing of bifunctional groups (carboxyl and pyridinyl), which have the potential capacity to coordinate with both uranyl and transition-metal center (such as silver ion) simultaneously. Actually, the introduction of a second nonuranium metal center in heterometallic uranyl–organic compounds , distinguishes them from uranyl–organic compounds with only uranyl nodes. ,− Hence, the comparison between heterometallic uranyl–silver and simple uranyl–organic compounds was conducted to figure out the role of silver ion (Table ). Note that, although several uranyl complexes with isonicotinic acid have been reported, those cases incorporating competing anions (such as NO 3 – , ReO 4 – , or TcO 4 – ) in the coordination sphere of uranium center are excluded from discussion for the sake of convenience, and only uranyl isonicotinate compounds with single isonicotinate ligand as well as hydro/water groups are included in Table .…”

Perrhenate and Pertechnetate Complexes of U(IV), Np(IV), and Pu(IV) with Dimethyl Sulfoxide as an O-Donor Ligand

“…In complexes with isonicotinic acid, the pertechnetate ion can act either as an outer-sphere anion ([NpO 2 (HisoNic) 4 ]­(TcO 4 ) 2 ·H 2 O) or as a monodentate ligand coordinated to the An cation ([UO 2 (HisoNic) 3 (TcO 4 ) 2 ]). Perrhenate ion was shown to enter into the environment of An atoms in [UO 2 (HisoNic) 3 (ReO 4 ) 2 ] and [NpO 2 (HisoNic) 2 (ReO 4 ) 2 (H 2 O)] complexes …”

What kind of interactions we may get moving from zwitter to “dritter” ions: C–O⋯Re(O4) and Re–O⋯Re(O4) anion⋯anion interactions make structural difference between l-histidinium perrhenate and pertechnetate

“…When analysing the Cambridge Structural Database (CSD version 5.43, update of November 2022; 33 ), only four structures were found in which there is this type of anion⋯anion interaction between the carboxyl group and the MO 4 (M = 7B group) fragment (the M⋯O distance is shorter than the sum of van der Waals radii and the carboxyl group (O–C–O angle 116–130°) is deprotonated): two structures with Mn (YATVEY, YATVIC 50 ) and two with Re (DEGXEV, 51 POMKUY 52 ). No interactions of this type have been found for technetium, which may be due to the presence of a small number of structures with it, or perhaps technetium does not form such interactions.…”