Theoretical IPPP analysis of ¹³C‐³¹ P through‐space indirect couplings in phosphorus‐substituted alkenes

Abstract

Abstract A refined version of the IPPP‐INDO method was used to analyse the difference between cis and trans 13 C‐ 31 P couplings in phosphorus‐substituted alkenes. A large through‐space transmission of the Fermi contact term is predicted for the cis 13 C‐ 31 P coupling. With the new version of the IPPP method it was assessed how different orbitals, describing chemically intuitive bonds, lone pairs and antibonding orbitals, contribute to the Fermi contact term. The importance of the P lone pair and C‐H bonds was clearly determined. The antibonding orbitals, which are very important but rarely mentioned, are also discussed.