Metal-organic chains constructed from pre-organized N2S2 donor ligands

Three new N2S2 donor ligands 1,1′-((2-(2-(phenylthio)phenylthio)phenyl)methylene)bis(3,5-R-1H-pyrazole), R = H (LH), R = Me (LMe), R = i-Pr (Li-Pr) have been prepared and characterized. These bifunctional ligands incorporate two distinct chelate donor systems, by virtue of the presence of bispyrazole and bisthioether functions. The preferred conformation of these ligands is such that the N2 and S2 donor moieties may be oriented in opposite directions, thus favoring the formation of molecular chains when treated with AgBF4. The X-ray structures of Ag(I) complexes show that, depending on the steric hindrance present on the pyrazole rings, these ligands behave as κ4-SSNN-μ bridging tetradentate (when R = H), or κ3-SNN-μ bridging tridentate (when R = Me, i-Pr). Interestingly, [Ag(LH)]BF4 crystallizes in the chiral space group P41, with the molecular chain that is folded around the 41 screw axis.

Graphical abstractThree novel N2S2 donor ligands were prepared. Their preferred conformation makes them suitable to build molecular chains, as evidenced by the X-ray structures of their Ag(I) complexes.Figure optionsDownload full-size imageDownload as PowerPoint slide