A polarization propagator analysis of the geminal 31P-31P coupling in bis(difluorophosphino)amine?

Indirect Nonbonded Nuclear Spin–Spin Coupling: A Guide for the Recognition and Understanding of “Through-Space” NMR J Constants in Small Organic, Organometallic, and Coordination Compounds

“…Conversely, although the experimental occurrence of unusually large spin–spin coupling constants observed in 31 P NMR between atoms separated by four chemical bonds or more is fairly frequent, it has been only rarely suggested that this is an abnormal or even simply a curious phenomenon with regard to fundamental NMR knowledge. Experimental and theoretical studies are now advanced enough to illustrate the significant impact of nonbonded J PP SSCCs on the structural determination of organophosphorus molecules as well as for metallocenic phosphines and other related coordination compounds. ,,,− …”

Analysis of Canonical Molecular Orbitals to Identify Fermi Contact Coupling Pathways. 1. Through-Space Transmission by Overlap of 31P Lone Pairs

“…The chosen examples take into account that it is well-known that a complex fragment containing a metal and two phosphorus nuclei offers the possibility of easily investigating the products by 31 P NMR spectroscopy determining the 2 J PP coupling. , A linear correlation between experimental through-space-transmitted J PP SSCCs and the P···P distance for ferrocenyl tetraphosphine coordination complexes has recently been observed . There are also many compounds with structures similar to those of 2a and 2b , where large values of J PP SSCCs suggest that the two P lone pairs overlap . In this context, it is important to analyze the performance of this new approach to rationalize the transmission mechanisms for J PP SSCCs.…”

Chapter 2. Nuclear magnetic resonance spectroscopy

“…The inner projection of the polarization propagator approach (IPPPA) in the RPA has been suggested as a means of separating the various spin transmission mechanisms?21 This procedure has been used, at the INDO level of approximation, in studies on the vicinal P-P coupling in cis-1,2-dephosphino ethylene,422 and on the geminal P-P coupling in bis(difluoroph0sphine) amine. 423 In the latter case it is found that the contact interaction dominates.423 The through-space component is larger than that which operates through the bonds connecting the coupled nuclei, and having the opposite sign. Both of these components of the contact interaction are found to be very sensitive to the value of the P-N-P angle.…”

“…423 In the latter case it is found that the contact interaction dominates. 423 In the latter case it is found that the contact interaction dominates.…”