1H and 31P NMR spectral analysis of the cis-trans equilibria of [NiX 2(Cy 2PH) 2] complexes: [AMY 2] 2 Spin Systems

Abstract

Analysis of 1H and 31P NMR of cis and trans isomers of {NiI 2[(C 6H 11) 2PH] 2}, {NiBr 2[(C 6H 11) 2PH] 2}, and of cis-{NiCl 2[(C 6H 11) 2PH] 2} is reported. Assignment of coupling constants in these compounds as [AMY 2] 2, spin systems and use of these assignments (particularly 2 J P−P′) in distinguishing cis and trans forms are discussed. The temperature dependence of the cis-trans equilibria of the bromide and iodide complexes, followed by the 31P spectra, is used to calculate thermodynamic constants for the isomerization.