In-Plane Thorium(IV), Uranium(IV), and Neptunium(IV) Expanded Porphyrin Complexes

James T Brewster 2nd; Daniel N Mangel; Andrew J Gaunt; Douglas P Saunders; Hadiqa Zafar; Vincent M Lynch; Michael A Boreen; Mary E Garner; Conrad A P Goodwin; Nicholas S Settineri; John Arnold; Jonathan L Sessler

doi:10.1021/jacs.9b09123

In-Plane Thorium(IV), Uranium(IV), and Neptunium(IV) Expanded Porphyrin Complexes

J Am Chem Soc. 2019 Nov 6;141(44):17867-17874. doi: 10.1021/jacs.9b09123. Epub 2019 Oct 25.

Authors

Affiliations

¹ Department of Chemistry , The University of Texas at Austin , Austin , Texas 78712 , United States.
² Chemistry Division , Los Alamos National Laboratory , Los Alamos , New Mexico 87545 , United States.
³ Department of Chemistry , University of California, Berkeley , Berkeley , California 94720 , United States.
⁴ Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States.

PMID: 31609114
DOI: 10.1021/jacs.9b09123

Abstract

Here we report the first series of in-plane thorium(IV), uranium(IV), and neptunium(IV) expanded porphyrin complexes. These actinide (An) complexes were synthesized using a hexa-aza porphyrin analogue, termed dipyriamethyrin, and the nonaqueous An(IV) precursors, ThCl₄(DME)₂, UCl₄, and NpCl₄(DME)₂. The molecular and electronic structures of the ligand, each An(IV) complex, and a corresponding uranyl(VI) complex were characterized using nuclear magnetic resonance (NMR) and UV-vis spectroscopies as well as single-crystal X-ray diffraction analysis. Computational analyses of these complexes, coupled to their structural features, provide support for the conclusion that a greater degree of covalency in the ligand-cation orbital interactions arises as the early actinide series is traversed from Th(IV) to U(IV) and Np(IV). The axial ligands in the present An(IV) complexes proved labile, allowing for the electronic features of these complexes to be further modified.