New phosphine ligands with the OPN donor configuration

Abstract

New, functionalised phosphines with an OPN donor set which are potentially capable of square planar co-ordination were synthesized by stepwise introduction of the oxygen and nitrogen functional substituents to phosphorus. The secondary phosphines (phenyl)(tetrahydrofurfuryl)phosphine, 1, and [2-(1,3-dioxolan-2-yl)ethyl](phenyl)phosphine, 2, were first prepared before the introduction of the nitrogen donor substituents. The OPN phosphines (phenylpyridylmethyl}, 3-5, were obtained. This approach was not appropriate for the preparation of an OPN ligand with an ester functionality. Therefore the synthesis of methyl 3-[(phenyl)(2-pyridylmethyl)phosphino]propanoate, 7, was achieved via a radical induced coupling of methyl acrylate to (phenyl)(2-pyridylmethyl)phosphine 6. All new ligands, 1-5, 7, were characterised by 1 H, 13 C and 31 P NMR spectroscopy. The methods developed allowed the ligands to be synthesized in high yields and purity such that further purification was generally unnecessary for subsequent applications.

New Palladium(II) Complexes with a Tridentate PNO Ligand

“…31 P NMR spectra of compounds (9)(10)(11)(12) show two doublet signals in the expected range, due to the PNO and the neutral ligand respectively and with a typical value of J P-P for cis-arrangement in complexes of square-planar geometry.…”

“…However, only a small number of heterotridentate phosphines exist which have both oxygen and nitrogen properly placed for metal coordination, taking the forms PNO, PON or OPN depending upon the relative position of the donors [10]. Several PNO ligands, typically built from a diphenylphosphine unit, and its respective complexes have been described [11][12][13][14][15][16][17][18], and interesting catalytic properties *Corresponding author.…”

Bridged 1-Methylbisimidazoles as Building Blocks for Mixed Donor Bi- and Tridentate Chelating Ligands

“…More recently the synthesis of well tailored chelating ligands containing nitrogen donors or a mixed set of donor atoms has received considerable interest in homogeneous catalysis and coordination chemistry. [1][2][3] As part of our ongoing interest in functionalised ligand systems, 4 we have chosen the bridged bisimidazoles 1 and 2 (Scheme 1) as building blocks for the synthesis of novel bi-and tridentate mixed donor ligands (N^P; N^N'; N^O^N; N^P^N).…”