Carbonyl Complexes of Triphenylphosphine, Triphenylarsine, and Triphenylstibine

IRON CARBONYL COMPLEXES OF TRIPHENYLPHOSPHINE, TRIPHENYLARSINE, AND TRIPHENYLSTIBINE 

Iron carbonyl phosphines were first mentioned by Reppe and Schweckendiek as products of the direct reaction 

Hallam and Pauson prepared [Fe(CO)a- (CeHs) sP 2] by heating triphenylphosphine in an autoclave with an equimolecular amount of [Fe(CO)2CeH6]2 or [FeCl(CO)2C5H5], or by treating [Fel2(CO)j (C.Hs)aP ] with cyclopentadienylsodium in tetrahydrofuran. Recently, Cotton and Parish obtained the phosphine derivatives by heating triphenylphosphine and iron pentacarbonyl in a Carius tube. It has been found possible to prepare both mono- and diphosphine derivatives, as well as the corresponding arsines and stibines, much more simply by reaction in an appropriate solvent.  

TETRACARBONYLMONO(TRIPHENYLPHOSPHmE)IRON AND TRICARBONYLBIS(TRIPHENYLPHOSPHmE)IRON 

Two grams (0.007 mol) of triphenylphosphine is dissolved in 100 ml. of dioxane or tetrahydrofuran. One gram (0.0020 mol) of triiron dodecacarbonyl (synthesis 46) is added, and the mixture is stirred in an atmosphere of nitrogen at a temperature of about 70° for 45 minutes, or until the green color of the solution completely disappears. The mixture is then cooled to room temperature, filtered, and the brow n residue washed with dioxane or tetrahydrofuran. The solvent is removed from the filtrate and washings by distillation under vacuum and the residue treated with 50 ml. of methanol or ethanol and cooled. A yellow crystalline product is obtained. The crystals are filtered, washed with two 10-ml. portions of petroleum ether, and sublimed under vacuum at 180°. The sublimate consists of [Fe(CO)4- (CeH6)jP ], which melts at 201 to 203° with decomposition. The residue from the sublimation is dissolved in a minimum amount of benzene, and the solution is filtered. The fil- 

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