119703-65-0Relevant academic research and scientific papers
Functionalized Isocyanides as Ligands. Part 5. Syntheses and Reactions of 3-(Benzylphosphonio)indolin-2-ylidene Complexes of Platinum(II). X-Ray Crystal Structure of trans-X(PPh3)2>BF4*2C2H4Cl2 (X=Cl or Br)
Michelin, Rino A.,Mozzon, Mirto,Facchin, Giacomo,Braga, Dario,Sabatino, Piera
, p. 1803 - 1812 (2007/10/02)
Reactions of the isocyanide o-ClCH2C6H4NC with benzylphosphines, PR3=P(CH2Ph)Ph2, P(CH2Ph)2Ph, or P(CH2Ph)3, in acetone at room temperature in the presence of excess of LiBr, yield the benzylphosphonium-substituted isocyanides Br, which are converted to the less hygroscopic tetrafluoroborate salts BF4 (L) 1), P(CH2Ph)2Ph (L2), or P(CH2Ph)3 (L3)> upon reaction with excess NaBF4 in acetone.The ligands, L, react with a mixture of cis- and trans- and NaBF4 to form the cationic complexes trans-BF4 1-L3>.Treatment of complexes (1a)-(3a) with a 10-fold excess of NEt3 in CH2Cl2 at room temperature leads to the cyclization reaction of the isocyanide ligands via phosphorus-ylide intermediates with the formation of 3-(benzylphosphonio)indolin-2-ylidene derivatives trans-Cl(PPh3)2>BF4 .Complexes (1a)-(3a) and (1b)-(3b) were characterized by their elemental analyses, i.r., 1H, and 31P n.m.r. spectra.The structure of trans-X(PPh3)2>BF4*2C2H4Cl2 (X=Cl or Br) was determined by X-ray diffraction: space group C2, a=21.946(1), b=14.097(3), c=19.801(1) Angstroem, β=96.95(1) deg, Z=4, R=0.037 (R'=0.041) for 4 802 independent reflections.The co-ordination geometry around the PtII atom is square planar with the indole ligand perpendicular to the plane.The Pt-C(sp2) distance is 2.036(8) Angstroem.The bond lengths within the condensed system indicate extensive electronic delocalization.Complex (1b) reacts with aqueous KOH in acetone at room temperature to give, in high yield, the platinaheterocycle (1c).Chloride abstraction by AgBF4 from (1c) and reaction of the cationic intermediate with OH(1-), CO, and PPh3 afford the corresponding derivatives (1d), (1e), spectively.
