Open AccessSynthesis and Characterization of Pyridine Dipyrrolide Uranyl Complexes
Author(s) -
Brett M. Hakey,
Dylan C. Leary,
Lauren M Lopez,
Leyla R Valerio,
William W. Brennessel,
Carsten Milsmann,
Ellen M. Matson
Publication year - 2022
Publication title -
inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 233
eISSN - 1520-510X
pISSN - 0020-1669
DOI - 10.1021/acs.inorgchem.2c00348
Subject(s) - chemistry , pyridine , tetrahydrofuran , deprotonation , ligand (biochemistry) , uranyl , medicinal chemistry , crystallography , cyclic voltammetry , redox , metathesis , inorganic chemistry , electrochemistry , organic chemistry , polymerization , ion , biochemistry , receptor , electrode , solvent , polymer
The first actinide complexes of the pyridine dipyrrolide (PDP) ligand class, ( Mes PDP Ph )UO 2 (THF) and ( Cl2Ph PDP Ph )UO 2 (THF), are reported as the U VI uranyl adducts of the bulky aryl substituted pincers ( Mes PDP Ph ) 2- and ( Cl2Ph PDP Ph ) 2- (derived from 2,6-bis(5-(2,4,6-trimethylphenyl)-3-phenyl-1 H -pyrrol-2-yl)pyridine (H 2 Mes PDP Ph , Mes = 2,4,6-trimethylphenyl), and 2,6-bis(5-(2,6-dichlorophenyl)-3-phenyl-1 H -pyrrol-2-yl)pyridine (H 2 Cl2Ph PDP Ph , Cl 2 Ph = 2,6-dichlorophenyl), respectively). Following the in situ deprotonation of the proligand with lithium hexamethyldisilazide to generate the corresponding dilithium salts (e.g., Li 2 Ar PDP Ph , Ar = Mes of Cl 2 Ph), salt metathesis with [UO 2 Cl 2 (THF) 2 ] 2 afforded both compounds in moderate yields. The characterization of each species has been undertaken by a combination of solid- and solution-state methods, including combustion analysis, infrared, electronic absorption, and NMR spectroscopies. In both complexes, single-crystal X-ray diffraction has revealed a distorted octahedral geometry in the solid state, enforced by the bite angle of the rigid meridional ( Ar PDP Ph ) 2- pincer ligand. The electrochemical analysis of both compounds by cyclic voltammetry in tetrahydrofuran (THF) reveals rich redox profiles, including events assigned as U VI /U V redox couples. A time-dependent density functional theory study has been performed on ( Mes PDP Ph )UO 2 (THF) and provides insight into the nature of the transitions that comprise its electronic absorption spectrum.