| Abstract
| - The complex [Ru(py)3([9]aneS3)][PF6]2, 1 (py = pyridine), has proved to be a suitable starting material for thesynthesis of heteroleptic Ru(II) complexes. By exploiting unfavorable steric interactions between 2-H and 6-Hhydrogens of coordinated pyridyl ligands, we have synthesized half-sandwich complexes incorporating the thiocrown[9]aneS3 and a variety of facially coordinated N-donor ligands. Such complexes are easily prepared: Stirring 1at room temperature in the presence of a suitable nitrile ligand leads to the exclusive substitution of one py ligandto produce complexes such as [([9]aneS3)Ru(py)2(NCMe)][PF6]2, 2. However, if the same reaction is carried outat higher temperatures, two py ligands are substituted, leading to complexes such as [([9]aneS3)Ru(py)(NCMe)2][PF6]2,3. An alternative approach to such heteroleptic species has also been developed which exploits the restrictedability of thioethers to neutralize positive charges through σ-donation. This phenomenon allows the synthesis ofheteroleptic complexes in a two-step procedure via monocationic species. By variation of the donor/acceptorproperties of ligands incorporated into the [Ru([9]aneS3)]2+ metal center, it is possible to tune the Ru(III)/Ru(II)redox couple over a range of >700 mV. The solid-state structures of 1−3 were confirmed by X-ray crystallographystudies. Crystal data: C22H30F12N4O2P2RuS3 (1·CH3NO2), monoclinic, Cc, a = 23.267(5) Å, b = 11.5457(18) Å,c = 26.192(5) Å, α = 90°, β = 114.836(10)°, γ = 90°, Z = 8; C18H25F12N3P2RuS3 (2), triclinic, P1̄, a =11.3958(19) Å, b = 11.4280(19) Å, c = 11.930(2) Å, α = 100.518(3)°, β = 100.542(3)°, γ = 112,493(3)°, Z =2; C15H23F12N3P2RuS3 (3), orthorhombic, Pna21), a = 14.748(5) Å, b = 18.037(18) Å, c = 10.341(5) Å, α =90°, β = 90°, γ = 90°, Z = 4.
- The complex [Ru(py)3([9]aneS3)][PF6)]2, 1 (py = pyridine), has been synthesized. Due to unfavorable steric interactions between coordinated ligands, 1 is a suitable starting material for the synthesis of a series of mono- and disubstituted pyridyl derivatives. An alternative approach to the synthesis of heteroleptic species, exploiting the restricted ability of thioethers to neutralize positive charges through σ-donation, has also been developed.
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