P,S,N-Hybrid Ligands And Correspondine Au/Pd Complexes: Synthesis And Application To Homogenous Catalysis

2-(1-Imidazolyl)thiazo le was utilized as a parent molecule to afford the monophosphines (1,2, and 6), biphosphine (4), and triphosphine (5) (scheme 1)respectively through controllable substitution of the active H-atoms in thiazolyl and imidazoly rings by--PPh2 groups with the presence of a strong base (n-BuLi), which were defined as P,S,N-ligands. The corresponding Au(I)-and Pd(II)-complexes were synthesized subsequently upon the complexation of the obtained P,S,N-ligands with the transition metal centers respectively(scheme 2). All the P,S,N-hybrid ligands and the corresponding Au(I)- and Pd(II)-complexes were fully characterized by NMR spectra, thermal gravimetric analysis (TG), UV-visible spectra, single crystal X-ray diffraction and other means. It is indicated that the Au(I)-centered vectors in each of these P,S,N-hybrid ligand-ligated Au(I)-complexes are all in the typical linear configurations, which are similar to that of Au(PPh3)CL But the electron density of the P atoms in which is generally higher than that of Au(PPh3)Cl. Compared with the mono-nuclear (8 and 9) and di-nuclear Au(I)-complexes (11), the tri-nuclear Au(I)-complex (12) exhibits the best structural and thermal stability. And the P,S,N-hybrid ligand ligated Pd(II)-complexes (15 and 16) possesses the typical square-planar geometry, which are structurally similar to trans-PdCl2(PPh3)2, which are coordinated respectively by two chloride ions and two phosphine ligands in trans-postions.When the Au(I)-complexes (8,9,11,12 and 13) were applied as the pre-catalysts for hydration of phenylacetylene, it was found that, free of any axillary additive, the complex 12 exhibited the best catalytic performance due to. the synergetic catalytic effect of the involved three different P-Au units. Comparatively, with the presence of additives (H2SO4 and AgOTf), the complex 8 corresponded to the best catalytic performance due to the relatively high electron density of P-atom with the exposed N-and S-sites for the good protection of the active P-Au+ intermediate.When the Pd(Ⅱ)-complexes (15 and 16) were applied as the pre-catalysts for carbonylative.Sonogashira reaction of aryl iodkles,it was found that,under the mild conditions,the complex 15 exhibited better catalytic performance than .in addition,when 15and 16 were disolved in the room temperative ionic liquid(RTIL) of,this cataly since the loss of Pd into the organic phase was completely avided.