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PINCER COMPLEXES

PINCER COMPLEXES. A SPECIAL TOPIC. Pincer Complexes. Complexes of mixed donor polydentate ligands pioneered by Shaw in mid-70s. Generic Structure of Pincer Complex. Dehydrogenation of Alkanes. Palladium Pincer Complexes as Catalysts for the Heck Reaction.

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PINCER COMPLEXES

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  1. PINCER COMPLEXES A SPECIAL TOPIC

  2. Pincer Complexes Complexes of mixed donor polydentate ligands pioneered by Shaw in mid-70s

  3. Generic Structure of Pincer Complex

  4. Dehydrogenation of Alkanes

  5. Palladium Pincer Complexes as Catalysts for the Heck Reaction

  6. Palladium Phosphinito PCP Pincer Complex in Heck Reactions Involving Aryl Chlorides CsOAC, 180oC, Dioxane

  7. The Classical Mechanism

  8. The Pd(II)/Pd(IV) Mechanism

  9. Platinum NCN and PCP pincer complexes as catalysts for alkane CH bond activation and functionalization

  10. Mechanism for the Shilov system

  11. Preparation of Pincer Complex synthesis of pincer ligand synthesis of metal precursor Metalation of pincer ligand

  12. Preparation of C6H4 -2,6 -(OPPri2)2 A solution of resorcinol (0.36 g, 3.28 mmol) and DMAP (0.81 g, 6.60 mmol) in THF (30 ml) was added a solution of ClPPri2 (1.0 g, 6.55 mmol) in THF (20 ml), while stirring at 0°C. The resulting mixture was allowed to reach room temperature (r.t.) and stirred for an additional 24 h. Following removal of the solvent in vacuo, the solid residue was extracted with toluene (220 ml). The combined extracts were filtered through a short plug of Celite and the toluene removed in vacuo to yield the product (1.1 g, 95%) as a colorless oil. NMR spectroscopy showed the product to be greater than 98% pure and it was used in further steps without further purification. 1H NMR (400.03 MHz, CDCl3): d 7.10–6.80 (m, 4H, arom.); 2.00–1.80 (m, 4H, CH(CH3)2); 1.15–1.00 (m, 24H, CH(CH3)2). 13C NMR (100.59 MHz, CDCl3): d 160.22 (s, ArC), 129.38 (s, ArC), 111.77 (s, ArC), 109.25 (s, ArC), 28.26 (d, 1JPC 17.9 Hz, PCH(CH3)2), 17.71 (s, PCH(CH3)2), 16.98 (s, PCH(CH3)2). 31P{1H} NMR (161.93 MHz, CDCl3): d 149.0. Anal. Calc. for C18H32O2P2 (342.40.): C, 63.14; H, 9.42. Found: C, 63.42; H, 9.74%.

  13. DMAP = 4 dimethylaminopyridine

  14. Preparation PdCl{C6H3 -2,6 -(OPPri2)} A toluene (50 ml) solution of C6H4-2,6-(OPPri2)2 (500 mg, 1.46 mmol), and PdCl2(COD) (417 mg, 1.46 mmol) was refluxed for 5 h. The solvent was evaporated under vacuum and the crude product was extracted with pentane. Following recrystalization from diethyl ether, a purified product was obtained (Yield 630 mg, 90 %). 1H NMR (400.03 MHz, CDCl3): d 1.20–1.40 (m, 24H, CH(CH3)2), 2.40–2.52 (sep m, 3JHH7.2 Hz, 4H, CH(CH3)2), 6.54 (d, 3JHH8.0 Hz, 2H, arom), 6.96 (t, 3JHH8.0 Hz, 1H, arom); 13C NMR (100.59 MHz, CDCl3) d 166.29 (bs, ArC), 149.84 (s, ArC), 128.02 (s, ArC), 105.94 (vt, JPC14.48 Hz, ArC), 28.78 (vt, JPC23.14 Hz, PCH(CH3)2), 17.26 (s, PCH(CH3)2), 16.69 (s, PCH(CH3)2); 31P NMR (161.93 MHz, CDCl3): d 187.68 (s, 1P). Anal. Calc. for C18H31Cl1O2P2Pd (483.24): C, 44.74; H, 6.47. Found: C, 44.49; H, 6.15%.

  15. Single-crystal X-ray diffraction study

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