Polydentate chalcogen reagents for the facile preparation of Pd-2 and Pd-4 complexes

摘要

The silylated organochalcogen reagents 1,2-(Me3SiSCH2)(2)C6H4, 1a and 1,2-(Me3SiSeCH2)(2)C6H4, 1b were prepared from the corresponding organobromides and lithium trimethylsilanechalcogenolate Li[ESiMe3] (E = S, Se). They have been characterized by multinuclear NMR spectroscopy (H-1, C-13, Se-77) and electrospray ionization mass spectrometry. 1a and 1b react under mild conditions with (1,3-bis(diphenyl-phosphino)propane)palladium(II) chloride, [PdCl2(dppp)], to provide the dinuclear organochalcogenolate-bridged complexes [(dppp)(2)Pd-2-mu-kappa S-2-{1,2-(SCH2)(2)C6H4}]X-2, [2a]X-2 and [(dppp)(2)Pd-2-mu-kappa Se-2-{1,2-(SeCH2)(2)C6H4}]X-2, [2b]X-2 (X = Cl, Br) in good yield, respectively. Furthermore, the tetranuclear palladium complex [(dppp)(4)Pd-4-mu-kappa S-4-{1,2,4,5-(SCH2)(4)C6H2}]X-4, [3]X-4 (X = Cl, Br) can be synthesized from the reaction of the tetrathiotetrasilane 1,2,4,5-(Me3SiSCH2)(4)C6H2, and [PdCl2(dppp)]. The structures of [2a]X-2, [2b]X-2 and [3]X-4 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 [2a]X-2 and [2b]X-2, UV-Vis absorption spectroscopy.