Interaction of organotin compounds with trans-carbonylchlorobis(triphenylphosphine)platinum(II) perchlorate

Abstract

The reactions of trans-[Pt(CO)Cl(PPh₃)₂][ClO₄] with aryltrialkyl-, tetra-aryl-, and tetra-alkyl-tin compounds (usually in dichloromethane) have been studied, mainly by ³¹P-{¹H} n.m.r. spectroscopy. Tetramethyltin gives trans-[Pt(CO)Me(PPh₃)₂][ClO₄] quantitatively at room temperature. With SnRMe₃ compounds (R = aryl) the main product is again trans-[Pt(CO)Me(PPh₃)₂][ClO₄], but trans-[PtR(Cl)(PPh₃)₂] is also usually produced, and sometimes trans-[Pt(CO)R(PPh₃)₂][ClO₄]. The styryl compound Sn(CHCHPh)Me₃ likewise gives mainly trans-[Pt(CO)Me(PPh₃)₂][ClO₄] together with trans-[Pt(CHCHPh)Cl(PPh₃)₂]. The neutral complexes such as trans-[PtR(Cl)(PPh₃)₂] may arise by loss of CO from trans-[Pt(CO)Cl(PPh₃)₂][ClO₄] to give [Pt₂Cl₂(PPh₃)₄][ClO₄]₂ followed by reaction of the latter with the excess of SnRMe₃. The reaction of trans-[Pt(CO)Cl(PPh₃)₂][ClO₄] with Sn(CH₂CHCH₂)Me₃ gives exclusively [Pt₂Cl₂(PPh₃)₄][ClO₄]₂ and this is also the main product from SnPh₄, but substantial amounts of trans-[PtPh(Cl)(PPh₃)₂] and trans-[Pt(CO)Ph(PPh₃)₂][ClO₄] are also formed in this case. Tetraethyltin gives initially trans-[Pt(CO)Et(PPh₃)₂][ClO₄], but this subsequently decomposes to give finally an unidentified complex. This is also formed from SnREt₃, SnRBuⁿ₃, and SnPrⁱ₄[and from SnMe₄ and Sn(C₆H₄OMe-p)Me₃ at higher temperatures], and is suggested to be a carbonyl-bridged platinum cluster complex. In reactions of SnMe₄, SnPh₄, Sn(C₆H₄OMe-p)Me₃, and SnPhMe₃, with trans-[Pt(CO)ClL₂][ClO₄]–cis-[PtCl₂L₂] mixtures (L = PEt₃ or PMe₂Ph), the cis-[PtCl₂L₂] species (which are normally inert to such organotin reagents) are brought into reaction, and this accounts for the substantial formation of trans-[PtMe(Cl)L₂] from SnMe₄. The complex trans-[Pt(CO)Cl(PPh₃)₂][ClO₄] reacts with PbPhMe₃ to give trans-[Pt(CO)Me(PPh₃)₂][ClO₄], trans-[PtMe(Cl)(PPh₃)₂], and cis-[PtMe₂(PPh₃)₂], together with trans-[PtPh(Cl)(PPh₃)₂], and the last complex is the sole product from PbPh₄. The reaction with Hg(C₆H₄Me-p)₂ gives the neutral aroyl complex trans-[Pt(COC₆H₄Me-p)Cl(PPh₃)₂] together with trans-[Pt(CO)(C₆H₄Me-p)(PPh₃)₂][ClO₄] and trans-[Pt(C₆H₄Me-p)Cl(PPh₃)₂]. Sodium tetraphenylborate gives exclusively trans-[Pt(CO)Ph(PPh₃)₂][ClO₄], and is the reagent of choice for this conversion. The GeRMe₃ and SiRMe₃ compounds examined did not react.