Preparation, Stereochemistry, and Reactivity of Linear-Type S-Bridged MCrIIIM (M = RhIII, IrIII) Trinuclear Complexes with 2-Aminoethanethiolate (aet). Crystal Structures of ΔΛ-[Cr{M(aet)3}2]3+

Abstract

S-Bridged trinuclear complexes, [CrIII{M(aet)3}2]3+, (M = RhIII (1), IrIII (2); aet = NH2CH2CH2S−) were newly prepared by the reaction of fac(S)-[M(aet)3] with chromium(III) nitrate. They were separated and optically resolved into the ΔΔ, ΛΛ, and ΔΛ isomers. Of these isomers for 1 and 2, the crystal structures of the ΔΛ isomers (1a and 2a) were determined by an X-ray diffraction method. Each of 1a and 2a consists of two fac(S)-[M(aet)3] subunits, a central Cr atom, three nitrates, and three water molecules, [Cr{M(aet)3}2](NO3)3·3H2O, in which three metals are aligned so as to be exactly linear. The central Cr atom is situated in an octahedral environment with the CrIIIS6 chromophore, which is formed by the coordination of two terminal fac(S)-[M(aet)3] units. The other isomers for 1 and 2 were characterized by the absorption and CD spectra, the molar conductivity, and the magnetic susceptibility. Each cyclic voltammogram of ΔΛ-[Cr{M(aet)3}2]3+ in water showed a reversible redox couple (M(IV)/M(III)) and an irreversible reduction wave (Cr(III)/Cr(II)). The stabilities of the S-bridged MCrIIIM complexes are also discussed in relation to the Cr–S bond strengths.

Synthesis of Novel S‐Bridged Heterotrinuclear Complexes Containing Six‐Membered Chelate Rings: Structural, Spectroscopic, and Electrochemical Properties of [Co{Rh(apt)3}2]3+ (apt = 3‐Aminopropanethiolate)

“…mol -1 ). [2,3,34,35] The structures of 2a, 2b, and 4a, determined by X-ray structural analysis, are shown in Figures 3, 4, and 5, respectively. The crystal structure of 4a was determined for purposes of comparison.…”

Kinetic Effect of Zinc(II) and Cadmium(II) Ions on Configurational Inversion of ΔLLL-fac(S)-Tris(l-cysteinato-N,S)cobalt(III) Complex

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] These S-bridged complexes are usually rather stable in solution and their optically active isomers exhibit quite strong circular dichroism (CD) spectral bands attributed to µ-thiolato sulfur-to-metal charge-transfers. While these S-bridged trinuclear complexes exhibit broad intense absorption bands in the whole spectral region characteristic of the S-bridged structure, the CD spectra exhibit positive and negative Cotton effects for each component of the electronic transitions.…”

Polymer‐Supported Optically Active fac(S)‐Tris(thiotato)rhodium(III) Complex for Sulfur‐Bridging Reaction With Precious Metal Ions

“…Such characteristics of the CD spectra are of great advantage to selective or simultaneous determinations for mixtures of analytes because a change in concentration of one analyte can be detected at λ Δε =0 for the other analytes. Recently, the inherent property of the CD spectra and the optical and chemical properties of the S ‐bridged complexes were applied to the selective and simultaneous CD spectropolarimetric determination of some metal ions using Δ LLL ‐ fac ( S )‐[Rh(L‐cys‐ N , S ) 3 ] 3− and optically resolved Λ ‐[Rh(aet) 3 ] …”

“…[5][6][7][8][9] Since fac(S)-[M(aet) 3 ] exists as a racemic mixture, we successfully carried out the optical resolution of sparingly soluble fac(S)-[Rh(aet) 3 ], 10 which is quite stable compared with the corresponding cobalt(III) complex without decomposition or racemization. The above fac(S)-tris(thiolato) complexes readily form the stable S-bridged linear-type trinuclear complexes with various metal ions such as Cr(III), 11 Fe(III), [12][13][14] Co, (III), 9,[15][16][17][18][19] and Ni(II) [20][21][22] and their optically active isomers, ΔΔ or ΛΛ, exhibit quite strong circular dichroism (CD) spectra attributed to the μ-thiolato sulfur-to-metal charge transfer characteristic of the bridged central metal ions (Fig. 2).…”

“…Recently, the inherent property of the CD spectra and the optical and chemical properties of the S-bridged complexes were applied to the selective and simultaneous CD spectropolarimetric determination of some metal ions using Δ LLL -fac(S)-[Rh(L-cys-N,S) 3 ] 3À and optically resolved Λ-[Rh(aet) 3 ]. [10][11][12][13][14] The above application of the S-bridging reactions are expected to extend to so-called precious metal ions such as gold(III), platinum(II), and palladium(II). Furthermore, if the S-bridged reaction can be performed on the polymersupported fac(S)-tris(thiolato)rhodium(III) complexes, it may be useful for extraction of the precious mete ions into the solid polymer phase.…”