Stereochemically non-rigid transition metal complexes of 2,6-bis[(1-phenylimino) ethyl]pyridine (BIP) Part 1. Dynamic NMR studies of [M(C6F5)2(BIP)](M = PdII or PtII)

Article abstract of DOI:10.1016/S0022-328X(96)06661-2

The complexes [M(C₆F₅)₂(BIP)] (M = Pd^II or Pt^II, BIP = 2,6-bis[(1-phenylimino)ethyl]pyridine) have been synthesised and characterised as involving BIP as a bidentate chelate ligand. In solution they undergo 1,4 metallotropic shifts of the M(C₆F₅)₂ moiety, E,Z isomerisation of the pendant imine bond, and restricted C - C rotation of the pendant portion of the BIP ligand. ¹H and ¹⁹F dynamic NMR studies yielded activation energies for these three types of fluxion. ΔG ^≠ (298 K) values for the three processes were 89.6, 86.6 and 47.4 kJ mol^-1 respectively for the Pt^II complex. Values for the Pd^II complex were significantly lower in magnitude, namely 71.6, 70.4 and 41.8 kJ mol^-1 respectively.