Platinum complexes with the SC6F4H-4 ligand – Synthesis, structures and spectroscopy

• Variations to prepare platinum(II) complexes with the SC6F4H-4 ligand.
• Single crystal XRD and NMR reveal structures and binding strength of the ligands.
• Multiple inter- and intramolecular π stacking of the SC6F4H-4 coligands.
• Marked contributions of the SC6F4H-4 ligand to the HOMO from UV–Vis and Echem.

The reaction of HSC6F4H-4 and base with suitable platinum(II) chlorido precursor complexes leads to mononuclear complexes containing diimine ligands [(N^N)Pt(SC6F4H-4)2], or [(N^N)Pt(Me)(SC6F4H-4)] (N^N = 2,2′-bipyridine (bpy), dipyrido[3,2-a:2′,3′-c]phenazine (dppz) or 11-trifluoromethyl-dipyrido[3,2-a:2′,3′-c]phenazine (CF3dppz)), cycloocta-1,5-diene (COD) complexes [(COD)Pt(SC6F4H-4)2] or [(COD)Pt(R)(SC6F4H-4)] (R = Me, Bn (benzyl) or C6F5), or phosphine complexes cis-[(PPh3)2Pt(SC6F4H-4)2], [(dppe)Pt(SC6F4H-4)2] (dppe = 1,2-bis(diphenylphosphino)ethane) and [(dppb)Pt(C6F5)(SC6F4H-4)] (dppb = 1,4-bis(diphenylphosphino)butane). Reaction of cis-[(DMSO)2PtCl2] lead to the labile cis- and trans-[(DMSO)2Pt(SC6F4H-4)2] which rapidly lose DMSO to yield polymeric [Pt(SC6F4H-4)2]m. Reaction of HSC6F4H-4 and KOtBu with K2PtCl4 gave K2[Pt(SC6F4H-4)4]. The new compounds were analysed and characterised by single crystal XRD, 1H, 19F and 195Pt NMR and IR spectroscopy. Both single crystal XRD (in the solid) and NMR (in solution) reveal that the ligand strength of the thiolate ligand −SC6F4H-4 strongly depends on the further ligands in the complexes. The crystal structures exhibit various inter- and intra molecular π stacking interactions of the SC6F4H-4 coligands. The absorption spectroscopy and electrochemistry of the diimine complexes [(N^N)Pt(SC6F4H-4)2] (N^N = bpy, dppz and CF3dppz) have been investigated and reveal that the Pt complexes are superior to the recently reported Pd derivatives in view of their application in photoactive materials.

Preparative routes to platinum(II) complexes with the SC6F4H-4 ligand have been explored and their structures and spectroscopy have been studied using single-crystal XRD, multi-nuclear NMR, and in part UV–Vis absorption spectroscopy and electrochemistry.Figure optionsDownload as PowerPoint slide