Photocatalytic Splitting of CS₂ to S₈ and a Carbon–Sulfur Polymer Catalyzed by a Bimetallic Ruthenium(II) Compound with a Tertiary Amine Binding Site: Toward Photocatalytic Splitting of CO₂?

The catalytic photocleavage of CS₂ to S₈ and a (C_xS_y)_n polymer with visible light using a dinuclear ruthenium(II) compound with a bipyridine units for photoactivity and a vicinal tertiary amine binding site for CS₂ activation was studied. The catalyst was characterized by X-ray diffraction, ¹H NMR, and ¹³C NMR, ESI-MS and elemental analysis. CS₂ photocleavage was significant (240 turnovers, 20 h) to yield isolable S₈ and a (C_xS_y)_n polymer. A mononuclear catalyst or one without an amine binding site showed significantly less activity. XPS of the (C_xS_y)_n polymer showed a carbon/sulfur ratio ∼1.5–1.6 indicating that in part both C–S bonds of CS₂ had been cleaved. Catalyst was also included within the polymer. The absence of peaks in the ¹H NMR verified the (C_xS_y)_n nature of the polymer, while ¹³C NMR and IR indicated that the polymer had multiple types of C–S and C–C bonds.