ISOLATION AND CHARACTERIZATION OF THE ACYL COMPLEXES TRANS-[PT(PPH(3))(2)(COR)CL] (R=(N)BU OR (S)BU) AND THEIR RELEVANCE TO THE HYDROFORMYLATION OF LINEAR BUTENES CATALYZED BY PLATINUM TIN/TRIPHENYLPHOSPHINE CATALYTIC-SYSTEMS - MOLECULAR-STRUCTURE OF CIS-[PT(PPH(3))(2)CL(SNCL3)]/

The acyl complex trans-[Pt(PPh(3))(2)(CO(eta)Bu)Cl] (A) has been synth esized by reaction of [Pt(PPh(3))(2)Cl-2] with 1-butene under 100 atm of CO at 80-100 degrees C, in ethanol. With 2-butene rather than 1-but ene under the same conditions, a mixture of the above acyl complex and of trans-[Pt(PPh(3))(2)(CO(s)Bu)Cl] (B) was formed. Complexes A and B do not interconvert. The new acyl complexes A and B have been charact erized by IR and H-1 NMR and C-13 NMR spectroscopy. The ratio A/B incr eases with PPh(3)/Pt ratio and with temperature. The formation of two isomers when 2-butene is used involves an isomerization process which is likely to be limited to the alkyl precursor complexes. The reactivi ty of complexes A and B has been tested in reactions with SnCl2, H-2, HCl and trans-[Pt(PPh(3))(2)HCl]. From the reaction solutions crystals of cis-[Pt(PPh(3))(2)Cl(SnCl3)] have been obtained. Its molecular str ucture has been determined by X-ray diffraction. The Pt atom has cis s quare planar coordination, with angular distortions due to steric fact ors. The strong trans influence of the SnCl3 group is confirmed by the lengthening of the trans Pt-P distance. The SnCl3 group has the pyram idal geometry found in all related compounds.