Preparation of highly reactive metal powders. Preparation and reactions of highly reactive palladium and platinum metal slurries

Abstract

apparatus and the distillate was examined by analytical GC °C depending on sample) and TLC (30% ether/ petroleum ether). Ketol 7, when present, appeared at a longer retention time and a smaller R¡ than enone 6. The product yields and physical data are recorded in Tables I and II. In some instances analytical samples were obtained by preparative GC or TLC.Method B. To a solution of 4 mmol of alcohol 4 in 6 mL of dry pyridine was added 2 mmol of phosphorus oxychloride, and the solution was refluxed under nitrogen for 2.5 h. The reaction mixture was cooled, 15 mL of water was added, and the cloudy mixture was extracted three times with ether (total volume ~100 mL). The combined organic phases were extracted with cold 6 N HC1 until all the pyridine was removed. The ether solution was transferred to a round-bottomed flask, 20 mL of 2 N HC1 was added, and the two-phase system was vigorously stirred at room temperature for 18 h to effect hydrolysis of the enol ether moiety. The aqueous phase was separated and extracted three times with ether, and the combined organic phases were extracted once with saturated NaHC03 solution and once with brine and then dried. After removal of the solvent, the residue was distilled with a Kugelrohr apparatus and analyzed by GC and TLC. Generally a small amount of unhydrolyzed diene 5 was detected and was found to have a shorter retention time and a larger Rf than those for enone 6.10 The yields of enone 6 for this procedure are reported in Table I.Conversion of 4 to Ketol 7. A solution of 4-5 mmol of crude Grignard product 4 in 100 mL of ether was stirred vigorously for 18 h with 25 mL of 5% H2S04. After the aqueous phase was extracted three times with ether, the combined organic phases were extracted once with a saturated NaHCOg solution and once with brine and then dried with anhydrous MgS04. Removal of the solvent yielded ketol 7 which exhibited carbonyl absorption at 1720 cm"1 in its IR spectrum and a singlet methyl carbinol resonance at 8 1.3 in its NMR spectrum.Acknowledgments. The authors acknowledge the financial assistance of the National Research Council of Canada.

Photophysical Properties of Endohedral Amine-Functionalized Bis(phosphine) Pt(II) Complexes as Models for Emissive Metallacycles

“…2,6-Bis(pyrid-4-ylethynyl) aniline ( 1 ), 2,6-bis(pyrid-3-ylethynyl) aniline ( 2 ), bromophenylbis(triethylphosphine)platinum, μ-1,4-phenylenetetrakis(triethylphosphine)bis(1,1,1-trifluoromethanesulfonato-κ O )diplatinum, bromo(4-methoxy)bis(triethylphosphine)-, ( SP -4-3)platinum ( 10 ), iodo(4-nitrophenyl)bis(triethylphosphine)-, ( SP -4-3)platinum ( 11 ), and bromophenylbis(triethylphosphine) palladium ( 12 ) were prepared using known procedures. All compounds were used as received from Sigma-Aldrich, Oakwood Chemicals, and TCI America, whereas deuterated solvents were purchased from Cambridge Isotope Laboratory (Andover, MA).…”

Palladium/phosphinated polystyrene as a catalyst in the Heck arylation. A comparative study

“…A dissolution of palladium metal has been observed in similar systems. 21 We therefore suggest that the catalytic cycle is extended to include a connection between palladium metal and ligated arylpalladium halide complex as outlined in Scheme I.…”

Photochemical Intermolecular Oxidative Addition of the C−Cl Bond of Chlorobenzene to Rhenium

“…96 kcal mol -1 in chlorobenzene) compared with C−Br or C−I, although mechanistic factors must be considered 3a. Chlorobenzene has been shown to react with Ni(PPh 3 ) 3 , Ni(bipy)Et 2 , Ni(PEt 3 ) 4 , Ni(COD)L 2 (L = bipy or tmed), Pd(PPh 3 ) 4 , Pd(PPh 3 ) 2 (dba), Pd(P(cyclohexyl) 3 ) 2 (dba), Pd(dippp) 2 , Pd(PEt 3 ) 3 , Pt(PEt 3 ) 3 , and Pt{P(cyclohexyl) 3 } 2 . − It was reported to react with Vaska's compound trans -IrCl(CO)(PPh 3 ) 2 to give evidence of the oxidative addition product (ν CO = 2050 cm -1 ), but this could not be isolated pure as do some uranium complexes .…”