Study on Platinum(II) Induced Formation of Dithiiranes

Abstract

The reaction of a series of stable alpha-chlorinated oligosulfanes 2 and 3 with [Pt(eta(2)-C(2)H(4))(Ph(3)P)2] 1 have been investigated. Starting with the alpha-chlorodisulfanes 2 a,b, the platinum dichloride complex 5 and the side-on bonded thioketone platinum complexes 6 a,b were formed. Complex 1 was treated with corresponding trisulfanes 3 a,b to give 5, 6 a,b and the dithiolatocomplexes 7 a,b. We assume that the {Pt(0)(Ph(3)P)2}-complex fragment inserted along the S--S bond to form the unstable intermediate G, which decomposed to form the products described above. We could prove that the sterically crowded 1,2,4-trithiolane 8 was not involved in the reaction pathway by treatment of 1 with 8 under the same conditions; after 24 h, 8 was found to be unreacted. X-ray structure analyses were performed on complexes 6 a, 7 a and 7 b.

ChemInform Abstract: The Topotactic Reduction of Sr3Fe2O5Cl2—Square Planar Fe(II) in an Extended Oxyhalide.

“…After 7 h, TLC analysis of the reaction mixture indicated the presence of two new compounds, which was further confirmed by the appropriate signals in the 31 P{ 1 H} NMR spectrum, in which a singlet accompanied by typical 195 Pt satellites at δ =25.86 ppm ( 1 J (P,Pt)=2940 Hz) and an AB spin system at δ =25.69/25.09 ppm ( 1 J (P,Pt)=4526/3088 Hz, 2 J (P,P)=10.7 Hz) were observed. As has been previously reported,4d, 9, 10a, b, 12, 13 this pattern is typical for a η 2 ‐thioketone complex. Owing to its chemical shift as well as its coupling constants, the AB spin system was easily identified as the known thiobenzophenone complex 9b 10a.…”

“…Owing to the methylene bridge, the S1‐Pt‐S2 angle decreased to 75.79(3)°. Key bond lengths and angles were comparable to those reported for similar dithiolato complexes 4d. 9, 10b The reaction of compound 6 and compound 1d occurred regioselectively, thereby resulting in the formation of only two products ( 8d and 9b ).…”

“…The alignment of the ligands around the Pt center is distorted square‐planar. In comparison with compound 8d and other complexes that contain a methylene‐bridged dithiolato unit,4d, 9, 10b the S1‐Pt‐S3 angle is significantly widened. As shown in Figure 2, the platinacycle adopts a twist‐conformation, which was rationalized as a result of the reduced electrostatic repulsion of the lone pairs on atoms S1 and S3.…”

“…The 31 P{ 1 H} NMR spectrum (recorded after 2.5 h) revealed only one singlet peak ( δ =25.59 ppm) with the corresponding 195 Pt satellites ( 1 J (P,Pt)=2965 Hz). Based on its spectroscopic data, this A 2 spin system was attributed to the known complex 8e 4d (Scheme…”

Organic and Coordination Chemistry of 1,2,4‐Trithiolanes

“…In analogy to 1,2,4‐trithiolanes, bisphosphane Pt(0) complexes react also with α,α′‐dichloroalkyl oligosulfanes prepared from monothioketone 2f yielding the corresponding platinathiirane of type 20 and the dithiolato Pt(II) complex 21c . Interestingly, in contrast to 1b , the sterically crowded 1,2,4‐trithiolane 1m did not react with (Ph 3 P) 2 Pt(η 2 ‐C 2 H 4 ) in toluene at room temperature for 24 h …”