Synthesis and Coordination Behavior of a Bipyridine Platinum(II) Complex with Thioglucose

A mononuclear platinum­(II) complex with two monodentate-<i>S</i> H₄tg^– ligands, [Pt­(H₄tg-κ<i>S</i>)₂(bpy)] (<b>1</b>), was newly synthesized by the reaction of [PtCl₂(bpy)] (bpy = 2,2′-bipyridyl) with NaH₄tg (NaH₄tg =1-thio-β-d-glucose sodium salt) in water. Complex <b>1</b> reacted with additional [PtCl₂(bpy)] in water to give an S-bridged dinuclear complex, [Pt₂(μ₂-H₄tg-κ¹<i>S</i>:κ¹<i>S</i>)₂(bpy)₂]²⁺ ([<b>2</b>]²⁺), in which a square-planar [Pt­(H₄tg)₂(bpy)] unit binds to a [Pt­(bpy)]²⁺ moiety through two thiolato groups. Treatments of <b>1</b> with Cu²⁺ and Ni²⁺ in water in the presence of bpy produced S-bridged dinuclear complexes [PtCu­(μ₂-H₄tg-κ¹<i>S</i>:κ²<i>O</i>,<i>S</i>)₂(bpy)₂]²⁺ ([<b>3</b>]²⁺) and [PtNi­(μ₂-H₄tg-κ¹<i>S</i>:κ²<i>O</i>,<i>S</i>)₂(bpy)₂]²⁺ ([<b>4</b>]²⁺), respectively, in which a square-planar [Pt­(H₄tg)₂(bpy)] unit binds to a [M­(bpy)]²⁺ (M = Cu^II, Ni^II) moiety through two thiolato and two hydroxyl groups to form a chiral [M­(N)₂(O)₂(S)₂] octahedron with the Δ configuration. On the other hand, similar treatment with Cd²⁺ in the presence of bpy resulted in the formation of an S-bridged trinuclear complex, [Cd­{Pt­(μ₂-H₄tg-κ¹<i>S</i>:κ²<i>O</i>,<i>S</i>)­(μ₂-H₄tg-κ¹<i>S</i>:κ¹<i>S</i>)­(bpy)}₂]²⁺ ([<b>5</b>]²⁺), in which each of two square-planar [Pt­(H₄tg)₂(bpy)] units binds to a Cd^II ion through two thiolato groups and one hydroxyl group to form a chiral [Cd­(O)₂(S)₄] octahedron with the Λ configuration. Of two geometrical configurations, syn and anti, which arise from the relative arrangement of two β-D-pyranose moieties, [<b>2</b>]²⁺ adopts the syn configuration with symmetric bridging sulfur atoms, while [<b>3</b>]²⁺, [<b>4</b>]²⁺, and [<b>5</b>]²⁺ all have the anti configuration with <i>R</i> configurational bridging sulfur atoms. All of the complexes were fully characterized by electronic absorption, CD, and NMR spectroscopies, along with single-crystal X-ray crystallography

Water-Molecule-Driven Vapochromic Behavior of a Mononuclear Platinum(II) System with Mixed Bipyridine and Thioglucose

A mononuclear platinum­(II) complex with mixed bpy and H₄tg^– ligands, [Pt­(H₄tg-<i>S</i>)₂(bpy)]·2H₂O (<b>1a</b>; bpy = 2,2′-bipyridine and H₅tg = 1-thio-β-d-glucose), is photoluminescent in the solid state and undergoes facile and reversible removal of solvated water molecules accompanied by changes in its absorption and emission wavelengths. The analogous dmbpy complex, [Pt­(H₄tg-<i>S</i>)₂(dmbpy)]·H₂O (<b>2a</b>; dmbpy = 4,4′-dimethyl-2,2′-bipyridine), is also emissive in the solid state, but its absorption and emission spectra remain unchanged after dehydration. X-ray crystallographic analyses revealed that the difference in the chromism of <b>1a</b> and <b>2a</b> is due to the difference in their hydrogen-bonding networks, which involve solvated water molecules