Polydentate chalcogen reagents for the facile preparation of Pd₂ and Pd₄ complexes

Abstract

The silylated organochalcogen reagents 1,2-(Me3SiSCH2)2C6H4, and 1,2-(Me3SiSeCH2)2C6H4, were prepared from the corresponding organobromides and lithium trimethylsilanechalcogenolate Li[ESiMe3] (E = S, Se). They have been characterized by multinuclear NMR spectroscopy ((1)H, (13)C, (77)Se) and electrospray ionization mass spectrometry. and react under mild conditions with (1,3-bis(diphenylphosphino)propane)palladium(ii) chloride, [PdCl2(dppp)], to provide the dinuclear organochalcogenolate-bridged complexes [(dppp)2Pd2-μ-κ(2)S-{1,2-(SCH2)2C6H4}]X2, []X2 and [(dppp)2Pd2-μ-κ(2)Se-{1,2-(SeCH2)2C6H4}]X2, []X2 (X = Cl, Br) in good yield, respectively. Furthermore, the tetranuclear palladium complex [(dppp)4Pd4-μ-κ(4)S-{1,2,4,5-(SCH2)4C6H2}]X4, []X4 (X = Cl, Br) can be synthesized from the reaction of the tetrathiotetrasilane 1,2,4,5-(Me3SiSCH2)4C6H2, and [PdCl2(dppp)]. The structures of []X2, []X2 and []X4 were determined by single crystal X-ray diffraction methods. A variety of NMR experiments including two-dimensional homonuclear and heteronuclear correlated spectra were used to probe the solution behaviour of the dinuclear complexes in more detail. These complexes were further characterized by electrospray ionization (ESI) mass spectrometry, and for []X2 and []X2, UV-Vis absorption spectroscopy.

Metal Trimethylsilylthiolates for the Synthesis of Trinuclear MnPd2 Complexes

“…The spectrum for 4 in THF reveals two peaks at 350 and 275 nm and a shoulder at 406 nm. The absorbance values below 300 nm can be assigned to the dppp ligands and are well documented for other diphosphine palladium(II) complexes . The shoulders at 320 and 410 nm for 2 and the peak at 350 and shoulder at 406 nm for 4 dominate the rest of the spectrum and trail out towards lower energy.…”

Tethered Polynuclear Copper–Chalcogenolate Assemblies Enabled via NHC Ligation

“…These molecules represent the first examples of the incorporation of such a large number of reactive −ESiMe 3 moieties onto an organic molecular scaffold. We also demonstrated the reactivity of −ESiMe 3 toward ferrocenoyl chloride as a simple route for the formation of polyferrocenyl­chalcogenoesters and the preparation of butterfly-shaped Pd 2 E 2 (E = S, Se) complexes via the reaction of [(dppp)­PdCl 2 ] (1,3-bis­(diphenylphosphino)­propane)­palladium­(II)) with the disubstituted thio- and selenotrimethylsilane reagents, 1,2-(Me 3 SiECH 2 ) 2 (C 6 H 4 ) . Taking advantage of the symmetrical distribution of chalcogen centers in 1,2,4,5-(Me 3 SiSCH 2 ) 4 (C 6 H 2 ) offers an entry into “double-butterfly” Pd 2 S 2 complexes, therefore demonstrating the use of such chalcogen reagents with defined spacers between the formed metal–chalcogenolate units …”