cis-[Pt(SeR)₂(PPh₃)₂] [R = ^tBu (1), ⁿBu (2)] can be synthesized by the reaction of RSeLi with cis-[PtCl₂(PPh₃)₂] in a molar ratio of 2:1. The reaction of equimolar amounts of cis-[PtCl₂(PPh₃)₂] and RSeLi (R = ^tBu, ⁿBu) produces a mixture containing cis-[Pt(SeR)₂(PPh₃)₂] and [PtCl(SeR)(PPh₃)₂] [R = ^tBu (3), ⁿBu (4)] in addition to unreacted cis-[PtCl₂(PPh₃)₂]. The direct reaction of ⁿBuLi with cis-[PtCl₂(PPh₃)₂] affords cis-[Pt(ⁿBu)₂(PPh₃)₂] (6). The complexes were characterized by ³¹P{¹H}, ¹⁹⁵Pt{¹H} and ⁷⁷Se NMR spectroscopy, as well as by singlecrystal X-ray crystallography. Unlike the corresponding arylselenolato complexes, 1 and 2 do not isomerize from cis- to trans-isomers upon standing in solution. However, they are not stable. For example, 2 slowly forms dinuclear [Pt₂(µ-SeⁿBu)₂(SeⁿBu)₂(PPh₃)₂] (5) due to the condensation of the mononuclear species. In the solid state, 1 and 2 crystallize as cis,antiisomers. It was furthermore observed that the n-butyl groups can adopt various conformations in different complexes. In order to model the structural properties and energetics of the mononuclear alkylselenolatoplatinum complexes, the geometries and relative stabilities of the isomers of [Pt(SeR)₂(PH₃)₂], [PtCl(SeR)(PH₃)₂] and [Pt(R)₂(PH₃)₂] (R = ⁿBu, ^tBu) were studied by density functional theory (DFT) molecular orbital (MO) techniques. The calculations also provide insight into the pathway of the reaction from cis-[PtCl₂(PPh₃)₂] to cis-[Pt(SeR)₂(PPh₃)₂] involving two successive substitution steps of Cl⁻ by RSe⁻.

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Ligand chemistry of alkylselenolates: an experimental and DFT study of the formation and structural characterization of [PtCl 2−x (SeR) x (PPh 3 ) 2 ] (x = 1,2;R = t Bu,n Bu)