Rearrangement of phosphinohydrazide ligand –NPh-N(PPh2)2 in transition metal coordination sphere: Synthesis and characterization of nickel and cobalt spirocyclic complexes M(NPh-PPh2N-PPh2)2 and their properties

A survey of pendant donor-functionalised (N,O) phosphine ligands for Cr-catalysed ethylene tri- and tetramerisation

“…Screening of ligand 8 resulted in the most selective trimerisation system of the series with an overall 1-hexene selectivity of 32%, albeit the activity of this ligand is also the lowest which might perhaps be attributed to its rearrangement, that has been known to occur upon deprotonation. 46 It is notable that, for ligands 4, 7…”

“…Interestingly, ligand 8 once again shows poor activity compared to the alkyl substituted species which is most likely due to its poor stability. 46 Activation of the pendant donor functionalised PNP ligands 9-13 with MAO yielded a series of selective oligomerisation systems. Ligand 9 displayed both the lowest activity and selectivity of the pendant donor functionalised systems screened (Table 6, entry 7), similar results have previously been demonstrated by Hor and co-workers for other pyridine functionalised PNP ligands.…”

The rearrangement of phosphitohydrazide ligand [(ArO)2P–NPh–NPh–] into iminophosphoranate anion [(PhNP(OAr)2–NPh–] {(ArO)2P = [CH2(tBuMeC6H2O)2P]} in coordination sphere of divalent cobalt

“…The nitrogen atom N(1) in 2 has a trigonal nearly planar environment (sum of the angles is 356, 45°). The P(1)-N(1) and N(1)-N(2) bond lengths in the molecule (1.698(2) and 1.420(3) Å, respectively) are typical for phosphazanes and phosphinohydrazines [2,5]. Note, however, the N-N bond distance in 2 is somewhat longer than that found in monophosphinohydrazine analog PhNH-NPh-PPh 2 (1.401(2)) [1].…”

“…Recently it was shown that rearrangements of mono-, bisand tris(diphenylphosphino)hydrazide ligands, Ph 2 P-NPh-NPh-, (Ph 2 P) 2 N-NPh-, (Ph 2 P) 2 N-N(PPh 2 )-, in the coordination sphere of nickel(II), cobalt(II) and iron(III) result in the formation of metal complexes of the phosphazene and phosphinoamide type depending on the starting ligand [1][2][3] (see Scheme 1).…”

“…The UV-vis spectrum of the solution of 3 in methylene chloride contains two absorptions with k max 384 and 565 nm. The complex 3 is the single product separated in the reaction(2). It is appeared impossible to separate the proposed intermediate(s) 4 during this slow reaction.…”