Synthesis, Coordination Chemistry, and Catalysis of the First 1,2-Bis(diphenylphosphino)-1,2-diphenylhydrazine, Ph₂PN(Ph)N(Ph)PPh₂

Abstract

The reaction of chlorodiphenylphosphine with dilithiohydrazobenzene gave 1,2-bis(diphenylphosphino)-1,2-diphenylhydrazine, [PPh 2 N(Ph)N(Ph)PPh 2 ] (1). Treatment of 1 with NiCl 2 (DME), PdCl 2 (PhCN) 2 , and PtCl 2 (COD) resulted in the formation of complexes of the type cis-[MCl 2 -{Ph 2 PN(Ph)N(Ph)PPh 2 }] (M = Ni (3), Pd (4), Pt ( 5)). The molecular structures of the starting ligand 1 and the complexes 3, 4, and 5 have been determined by X-ray diffraction. The ligand 1 and its Ni(II) complex 3 were evaluated for their catalytic activity in the oligo-/polymerization of ethylene using methylaluminoxane (MAO) and triethylaluminium (TEA) as cocatalyst.

A Mixed Valent Trinuclear Nickel Complex

“…Both Ni1–Cl distances [Ni1–Cl1 = 2.2060(8) Å, Ni1–Cl2 = 2.1846(8) Å] conform values for other Ni(PPhNR) 2 Cl 2 compounds (Ni–Cl range from 2.1838 Å to 2.209 Å) as published by Ghosh et al, Rosenthal et al, and Daly et al…”

Ethylene oligomerisation chromium catalysts with unsymmetrical PCNP ligands

“…The chemical shifts of these doublets in 2a-d were all very similar and at approx. δ −21 (PCH 2 ) and δ 68 (PN) ppm 10,14 indicating that small changes in the R 1 aromatic substituent have negligible effect on the electronic properties of the P nuclei. The absence of an NH resonance in the 1 H NMR spectra and of a ν(NH) stretch in the IR spectra confirmed that the amine group has successfully been replaced by a -PPh 2 group.…”

“…10 Inspired by these findings, chemists have sought to explore the scope of Group 15/16 ligands for Cr-catalysed ethylene oligomerisations 11,12 and polymerisations. 13 Some examples of P-based ligands studied, for ethylene tri-/tetramerisations, highlight the vari-ation of backbone groups including -NN-, 14,15 -CC- 16,17 and -NSi-(shown in Chart 1). 18 Whilst significant advances in ligand design have aided catalyst performance, there have also been considerable computational [19][20][21][22] and mechanistic [23][24][25] efforts to probe the nature of catalytically important Cr-based intermediates, and the origin of 1-hexene and 1-octene selectivities.…”

PNPN‐H in Comparison to other PNP, PNPN and NPNPN Ligands for the Chromium Catalyzed Selective Ethylene Oligomerization

“…For comparison purposes, the Ni(0) complex [Ni{Ph 2 PN( i Pr)P(Ph)NH( i Pr)‐ P,P′ } 2 ], the M(II) complexes cis ‐[NiX 2 {Ph 2 PN( i Pr)P(Ph)NH( i Pr)‐ P,P′ }] with M=Ni, Pd, Pt, X=Cl or Br and the iron complex trans ‐[Fe(CH 3 CN) 2 {Ph 2 PN( i Pr)P(Ph)NH( i Pr)‐ P,P′ } 2 ](BF 3 ) 2 were prepared. In all of these complexes, by coordination of both P atoms four membered M−P−N−P metallacycles were formed with no interaction between the metal and the N atoms.…”