Phosphine Coordination to Ce, Nd, Np, and Pu in Ar BiAMP t Bu ‐Supported Complexes and Their 2 H and 13 C Isotopologues

Abstract

ABSTRACT 13 C‐ and 2 H‐enriched bis((3,5‐dimethylphenyl)aminomethyl) tert butylphosphine (the natural abundance (NA) ligand Ar BiAMP t Bu ; the 2 H‐ and 13 C‐labelled analogues are denoted as d 4 ‐ Ar BiAMP t Bu and 13 C 2 ‐ Ar BiAMP t Bu , respectively), containing two secondary amines and a tertiary phosphine, was synthesized using a Kabachnik–Fields protocol. The coordination chemistry of the ligand isotopologues (including the NA derivative) was investigated with the paramagnetic lanthanides Ce and Nd and the paramagnetic actinide elements Np and Pu, furnishing MI( Ar BiAMP t Bu )(thf) 3 (M = Ce( 1 ), Nd( 2 ), Np( 3 ), Pu( 4 )), MI( d 4 ‐ Ar BiAMP t Bu )(thf) 3 (M = Ce( 2 H‐1 ), Nd( 2 H‐2 )) and MI( 13 C 2 ‐ Ar BiAMP t Bu )(thf) 3 (M = Ce( 13 C‐1 ), Nd( 13 C‐2 ), Np( 13 C‐3 ), Pu( 13 C‐4 )); each complex bears the metal in the 3+ oxidation state chelated by the amide groups and phosphorus atom of the Ar BiAMP t Bu ligand. Multinuclear ( 1 H, 31 P, 13 C, and 2 H) NMR characterization of the complexes revealed wide windows of paramagnetically shifted resonances; the isotopically enriched derivatives allowed for the unambiguous identification of the methylene environments, highlighting the utility of the Ar BiAMP t Bu ligands for providing rich spectroscopic signatures of paramagnetic f ‐element coordination complexes. A combination of single‐crystal X‐ray diffraction and UV‐vis‐NIR spectroscopic techniques was also employed for the characterization of the compounds. Actinide complexes 3 and 4 possess rare examples of molecular transuranium element–phosphorus bonds and the first examples of transuranium element–phosphine interactions.