Degree Name

Master of Science (MS)

Semester of Degree Completion

1985

Thesis Director

Richard L. Keiter

Abstract

Two heterobimetallic complexes, [(CO)4W(PPh2CH2CH2-PPh2)2MCl2]n ( M = Pd or Pt ), were prepared from the reaction of trans-W(CO)4(ŋ1-PPh2CH2CH2PPh2) 2 with M(COD)Cl2 (COD = cyclooctadiene). A trans arrangement about tungsten was found for both the palladium and platinum complexes. The square planar palladium center was shown to have a trans geometry in solution while a cis arrangement for the platinum moiety was observed. Far infrared studies indicated a mixture of cis and trans isomers in the solid state for the platinum center. The solubility of the bimetallic complexes precluded solution molecular weight studies and as a result the value of n has not been determined.

Preliminary results for the reaction of trans-W(CO)4-(PPh2CH=CH2)2 with Pt(PPh2H) 2Cl2 in the presence of base lead to unidentified products. This method does not appear promising for the preparation of bimetallic compounds.

The reaction of W(CO)6 with PPh2CH=CH2 in n-butanol in the presence of NaBH4 yielded the starting material, trans-W(CO)4(PPh2CH=CH2) 2 in 31% yield. It appears that the less soluble trans isomer precipitates from a solution containing an equilibrium mixture of cis and trans isomers. The vinyl complex was converted to trans-W(CO)4-(ŋ1-PPh2CH2CH2PPh2) 2 by allowing it to react with PPh2H in the presence of potassium t-butoxide. Some isomerization and cyclization led to the formation of W(CO)4-[PPh2CH2CH2CH(PPh2)CH2PPh2], obtained as minor product.

It was not possible to prepare W(CO)4(PPh2H) 2 from the reaction of W(CO)6 with PPh2H in the presence of NaBH4. This reaction led to the formation of (OC)4W-(PPh2) 2W(CO)4, (CO)4W(PPh2) 2W(CO)3PPh2H and an unidentified product.

The reaction of fac-W(CO)3(PPh2CH=CH2)3 with PPh2H in the presence of base gave W(CO)3(ŋ2-PPh2CH2CH2PPh2)-(ŋ1- PPh2CH2CH2PPh2) instead of fac-W(CO)3(ŋ1-PPh2CH2CH2-PPh2)3.

Proton decoupled phosphorus-31 NMR and infrared spectra, along with elemental analyses, were used to determine the structures of the compounds. Computer methods were used to simulate NMR spectra of trans-W(CO)4-(ŋ1-PPh2CH2CH2PPh2) 2, (CO)4W(PPh2CH2CH2PPh2) 2PtCl2, and W(CO)3(ŋ2-PPh2CH2CH2PPh2)(ŋ1-PPh2CH2CH2PPh2).

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