Phosphorus-31-Phosphorus-31 spin-spin coupling in metal complexes of phosphorus ligands

Synthesis of NPN-Coordinated Tantalum Alkyl Complexes and Their Hydrogenolysis: Isolation of a Terminal Tantalum Hydride Incorporating a Doubly Cyclometalated NPN Scaffold

“…The tantalaaziridine motif was left unchanged, as indicated by a broadened 1 Similarly, two well-separated, mutually coupled signals were found for the CH 2 moiety of the trimethylsilylmethyl group. On the basis of the 2 J P,P coupling constant noted above, 78,79 a trans alignment of both P donors was anticipated and confirmed by singlecrystal X-ray diffraction (see Figure 6). Two independent molecules with very similar molecular structures were found to be present in the crystal (cf.…”

“…The molecular structure of 8 (see Scheme 7) was then elucidated by single-crystal X-ray diffraction (see Figure 7), and the terminal hydride was located cis to the ligand's phosphine. This allowed for an assignment of the 31 P{ 1 H} NMR signals on the basis of the 2 J P,P coupling constants, 78,79 the molecular structure, and the 1 H, 31 P COSY NMR spectrum (26.0 ppm (P1) with 2 J P1,P3 = 24 Hz, 2 J P1,P2 = 77 Hz, 18.3 ppm (P3) with 2 J P1,P3 = 24 Hz, 16.3 ppm (P2) 2 J P1,P2 = 77 Hz). Interestingly, both C−N vectors of the tantalaaziridines (C22−N2 and C7− N1) in 8 are nearly collinear and span a plane which also includes the central tantalum atom.…”