Reaction of “Non‐Symmetrical” 1,2,4‐Trithiolanes with [(phosphane)Pt⁰(η²‐nbe)] Complexes

Abstract

Two unsymmetrical 1,2,4-trithiolanes (1d and 1e) were reacted with [Pt(0)(PPh(3))(2)(η(2)-nbe)] (6; nbe=norborn-2-ene) and [Pt(0)(dppn)(η(2)-nbe)] (11; dppn=1,8-bis(diphenylphosphanyl)naphthalene)), respectively. Their treatment with compound 6 resulted in the formation of six-membered platinacycles of type 7, which selectively underwent fragmentation into dithiolato complexes and thiobenzophenone (4b). The isolation of the first stable C-substituted member of this class of compounds (i.e., compound 7e) permitted kinetic studies of this process by using UV/Vis spectroscopy. These results, together with DFT calculations, allowed us to propose a mechanism for the reactions of compound 6 with 1,2,4-trithiolanes. In contrast, similar treatment of compound 11 with compounds 1d and 1e at room temperature did not result in any reaction. Heating the appropriate samples to 110 °C led to the formation of dithiolato complexes and η(2)-thioketone compounds, thus pointing to a thermally induced [3+2]-cycloreversion of the heterocycles as an initial step of the reaction.

Diferrocenyl Thioketone: Reactions with (Bisphosphane)Pt(0) Complexes—Electrochemical and Computational Studies

“…In addition, platinathiirane 3d was prepared from thiobenzophenone ( 1b ) and 2c . Three of the four complexes 3a – d have been characterized using XRD methods revealing that the bond lengths in the platinathiirane rings correspond to the data reported for similar platinaheterocycles derived from several aryl and cycloaliphatic thioketones [16,17,18,47]. Compounds 3a – d were characterized electrochemically using CV.…”

“…Subsequent (3 + 2)-cycloelimination of the intermediate formed thereby, releases the corresponding thioketone which in the next step interacts with another equivalent of 2 forming platinathiiranes 3 . In these multi-step reactions, the second type of products formed, was identified as four membered (dithiolato)platinum(II) complexes 4 [17].…”

Thioformaldehyde S-Sulfide, Sulfur Analogue of the Criegee Intermediate: Structures, Energetics, and Rovibrational Analysis

“…However, cycloreversion proved a successful strategy for studying the sulfur analogue, thioformaldehyde S -sulfide (CH 2 SS; 2b in Figure ). Indeed, Maier and co-workers showed via matrix isolation that the thermal fragmentation of 1,2,4-trithiolane ( 2a ), a stable substance that is common in nature, − yields CH 2 SS ( 2b ) and the companion product dithiirane (H 2 CS 2 ; 2c in Figure ) in a ratio of 1:2.5. Complete conversion to 2c was achieved photochemically through irradiation of the product mixture with visible light (λ > 570 nm).…”

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

“…Similar studies performed with differently substituted 1,2,4‐trithiolanes demonstrated that the “dithiirane mechanism” shown in Scheme has to be replaced by the alternative ring‐expansion of the starting 1,2,4‐trithiolane 1 resulting in the formation of six‐membered Pt‐heterocycles 22 , which undergo thermal decomposition with release of the corresponding thioketone, which is subsequently trapped by another bisphosphane Pt(0) complex, (Scheme ). The postulated six‐membered intermediate formed from 1n and (Ph 3 P) 2 Pt(η 2 ‐nbe) is stable at room temperature, and its structure was confirmed not only spectroscopically but also by X‐ray crystallography …”