Tetrakis triethylphosphine platinum

Submitted by T. YOSHIDA, T. MATSUDA, and S. OTSUKA Checked by G. W. PARSHALLt and W. G. PEETt 

Tetrakis(triethylphosphine)platinum(0) is extremely air sensitive and readily soluble in saturated aliphatic hydrocarbons. The complex can be stored under dry nitrogen in a freezer (-35°) for several months. The complex readily loses one of the coordinated phosphine molecules to give Pt(PEt3)36 (dissociation constant (K ) in heptane is 3.0 X 10 ). The H NMR spectrum measured in benzene-d6 shows two multiplets at 5 1.56 (CH2) and 1.07 ppm (CH3). Tetrakis-(triethylphosphine)platinum(O) is a strong nucleophile and reacts readily with chlorobenzene and benzonitrile to give a-phenyl complexes PtX(Ph)(PEt3)2 (X = Cl, CN).7 Oxidative addition of EtOH affords [PtH(PEt3)3] +. 

Shriver, Manipulation of Air-Sensitive Compounds, McGraw-Hill Book Co., New York, 1969. 

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Caution. Triethylphosphine and tetrakis(triethylphosphine)platinum(0) are extremely air-sensitive. The phosphine is malodorous and toxic. Therefore all... 

A solution of 20.8 g. (55 mmoles) of potassium tetrachloro-platinate(II) in 100 ml. of water is prepared in a 250-ml. suction flask with a nitrogen flow through the sidearm to provide an inert atmosphere. (The procedures work equally well at halfscale.) Triethylphosphine (15 ml., 100 mmoles) is added all at once and the mixture is stirred with a magnetic stirrer at room temperature for one hour. A pink-tan precipitate of tetrakis-(triethylphosphine)platinum(II)tetrachloroplatinate(II) forms. The mixture is heated on a steam bath for one hour. The pink salt dissolves, and a layer of pale yellow dichloro-bis(triethyl-phosphine)platinum forms on the liquid. The solid is filtered, washed with water, crushed in a mortar, and dried under... 

Hexagonal macrocycle 50 is produced from a 120°-angle-tecton 33 and 120°-angle-linker 49 <19990L1921> (Scheme 8). Tecton 33 is prepared by double oxidative addition of 4,4 -diiodobenzenophenone 47 with tetrakis(triethylphosphine)platinum(ll) followed by treatment with AgOTf. Bis(4-pyridyl)ketone 49 combines spontaneously with 33 at room temperature to form metallocycle 50. 

Oxidative addition into the transition-metal center is an important reaction in organometallic chemistry. The Cl-C bond in dichlorophosphaethene is sensitive to this oxidative addition. Thus, the Mes -substituted 2,2-dihalophosphaethene 2 was allowed to react with tetrakis(triethylphosphine)platinum(0) to afford the corresponding complex 14 to result in the formation of diplatinum complex 15 [27] (Scheme 9). Bis(trimethylsilyl)amino-substituted dichlorophosphaethene 16 was treated with a nickel(O) reagent to afford the corresponding nickel(II) complex 17 [28] (Scheme 10). Complex 14 displays a carbenoid reaction as mentioned in Sect. 4. 

Transition-metal induced [1,2]-rearrangement is also available to obtain phosphaalkyne 39. Dichlorophosphaethene 2a was allowed to react with an equivalent amount of tetrakis(triphenylphosphine)palladium(0) to afford phosphaalkyne 39 through intermediates (Scheme 21) [37]. The rearrangement process takes place in the reaction of dibromophosphaethene 2b with a small amount (0.2 equiv.) of dibromobis(triphenylphosphine)nickel(II) in the presence of zinc and tetraethylammonium iodide through the generation of a nick-el(0) intermediate [38]. Complex 43 was isolated in the reaction of 2a and tetrakis(triethylphosphine)platinum(0) which could afford phosphaalkyne 39 [27,28,39]. 

A 15-mL Schlenk flask is evacuated and refilled with nitrogen three times. Tetrakis(triethylphosphine)platinum (0.66 g, 1 mmol) is charged by the Schlenk-tube techniques. Under a nitrogen flow the flask is connected to a vacuum line through a liquid nitrogen U trap. Tie flask is heated at 50-60° at reduced pressure (S torr) for 6 h to give an orange-red viscous oil. Yield 0.49 g (90%). 

H2BP4PtC,4H3i, Platinum(IlX /i-hydrido-hydridophenyl-tetrakis(triethylphosphine)ditetta-phenylborate( 1—X 26 136 H2Fe309 C9, Iron, nonacarbonyldihydiido-IJj-thiotri-, 26 244... 

PtP4C24H8 , Platinum(O), tetrakis(triethyl-phosphine)-, 28 122 PtP4C,2H8o, Platinum(O), tetrakis(tri-phenylphosphine)-, 28 124 Pt2BH3P4C4,H8o, Platinum(II), di-p-hydrido-hydridotetrakis(triethylphosphine)di-, tetraphenylborate( I -), 27 34... 

PrCl2Li02Si4C3oH,g, Praseodymium, bis[q -1,3-bis(trimethylsilyl)-cyclopentadienyl]di- -chloro-bis(tetrahydrofuran)lithium-, 27 170 PrOjCgsHgj, Praseodymium, tris(2,6Kli tert-butyl-4-methylphenoxoK 22 167 Pr2Cl2Si4C44H 4, Praseodymium, tetrakis-[if -l,3-bis(trimethylsilyl)-cyclopentadienyl]di-/t-chloro-di-, 27 171 PtAu2CIFj03P4SC4,Hjo. Platinum(l-l-), chloro-1 -kC lbis(triethylphosphine-... 

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