Synthesis
and Coordination Behavior of a Bipyridine Platinum(II) Complex with
Thioglucose
- Publication date
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Abstract
A mononuclear platinum(II) complex
with two monodentate-<i>S</i> H<sub>4</sub>tg<sup>–</sup> ligands, [Pt(H<sub>4</sub>tg-κ<i>S</i>)<sub>2</sub>(bpy)] (<b>1</b>), was newly synthesized by the reaction of
[PtCl<sub>2</sub>(bpy)] (bpy = 2,2′-bipyridyl) with NaH<sub>4</sub>tg (NaH<sub>4</sub>tg =1-thio-β-d-glucose sodium
salt) in water. Complex <b>1</b> reacted with additional [PtCl<sub>2</sub>(bpy)] in water to give an S-bridged dinuclear complex, [Pt<sub>2</sub>(μ<sub>2</sub>-H<sub>4</sub>tg-κ<sup>1</sup><i>S</i>:κ<sup>1</sup><i>S</i>)<sub>2</sub>(bpy)<sub>2</sub>]<sup>2+</sup> ([<b>2</b>]<sup>2+</sup>), in which a
square-planar [Pt(H<sub>4</sub>tg)<sub>2</sub>(bpy)] unit binds to
a [Pt(bpy)]<sup>2+</sup> moiety through two thiolato groups. Treatments
of <b>1</b> with Cu<sup>2+</sup> and Ni<sup>2+</sup> in water
in the presence of bpy produced S-bridged dinuclear complexes [PtCu(μ<sub>2</sub>-H<sub>4</sub>tg-κ<sup>1</sup><i>S</i>:κ<sup>2</sup><i>O</i>,<i>S</i>)<sub>2</sub>(bpy)<sub>2</sub>]<sup>2+</sup> ([<b>3</b>]<sup>2+</sup>) and [PtNi(μ<sub>2</sub>-H<sub>4</sub>tg-κ<sup>1</sup><i>S</i>:κ<sup>2</sup><i>O</i>,<i>S</i>)<sub>2</sub>(bpy)<sub>2</sub>]<sup>2+</sup> ([<b>4</b>]<sup>2+</sup>), respectively,
in which a square-planar [Pt(H<sub>4</sub>tg)<sub>2</sub>(bpy)] unit
binds to a [M(bpy)]<sup>2+</sup> (M = Cu<sup>II</sup>, Ni<sup>II</sup>) moiety through two thiolato and two hydroxyl groups to form a chiral
[M(N)<sub>2</sub>(O)<sub>2</sub>(S)<sub>2</sub>] octahedron with the
Δ configuration. On the other hand, similar treatment with Cd<sup>2+</sup> in the presence of bpy resulted in the formation of an S-bridged
trinuclear complex, [Cd{Pt(μ<sub>2</sub>-H<sub>4</sub>tg-κ<sup>1</sup><i>S</i>:κ<sup>2</sup><i>O</i>,<i>S</i>)(μ<sub>2</sub>-H<sub>4</sub>tg-κ<sup>1</sup><i>S</i>:κ<sup>1</sup><i>S</i>)(bpy)}<sub>2</sub>]<sup>2+</sup> ([<b>5</b>]<sup>2+</sup>), in which each
of two square-planar [Pt(H<sub>4</sub>tg)<sub>2</sub>(bpy)] units
binds to a Cd<sup>II</sup> ion through two thiolato groups and one
hydroxyl group to form a chiral [Cd(O)<sub>2</sub>(S)<sub>4</sub>]
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>]<sup>2+</sup> adopts the syn configuration
with symmetric bridging sulfur atoms, while [<b>3</b>]<sup>2+</sup>, [<b>4</b>]<sup>2+</sup>, and [<b>5</b>]<sup>2+</sup> 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
