Nuclear magnetic resonance studies of chelate-ring effects in tungsten(0) carbonyl complexes of poly(tertiary phosphines)

Abstract

Magnetic multiple-resonance experiments have been used to determine the absolute signs of the various ³¹P–³¹P spin-coupling constants in tungsten carbonyl complexes of the ligand Ph₂PCH(CH₂PPh₂)CH₂CH₂PPh₂. Apparently anomalous values of these coupling constants may thereby be accounted for in simple terms and shown to be consistent with earlier ideas on the effects of chelate-ring formation on n.m.r. parameters.