Preparation and Some Properties of Linear-Type S-Bridged IrIIICoIIIIrIII Trinuclear Complexes with 2-Aminoethanethiolate (aet) or l-Cysteinate (l-cys). Crystal Structure of ΔΛ-[Co{Ir(aet)3}2](NO3)3

Abstract

The reactions of newly prepared fac(S)-[IrIII(aet)3] or ΔLLL-fac(S)-[IrIII(l-cys-N,S)3]3− with Co2+, followed by the air or H2O2 oxidation, gave linear-type S-bridged trinuclear complexes, [CoIII{IrIII(aet)3}2]3+ and ΔLLLΔLLL-[CoIII{IrIII(l-cys-N,S)3}2]3−. The aet trinuclear complex was separated and optically resolved into the ΔΛ, ΔΔ, and ΛΛ isomers and the crystal structure of the ΔΛ isomer was determined by X-ray diffraction. [Co{Ir(aet)3}2](NO3)3·2H2O, chemical formula C12H40N9S6O11CoIr2, crystallizes in the triclinic, space group with a = 8.945(2), b = 12.073(3), c = 8.849(3) Å, α = 110.36(2), β = 102.55(2), γ = 70.88(2)°, U = 841(2) Å3, Z = 1, and R = 0.059. The central Co(III) has a trigonally distorted octahedral geometry, coordinated by six thiolato sulfur atoms from the octahedral Δ- and Λ-fac(S)-[Ir(aet)3] terminals. The other trinuclear complexes were characterized by their absorption, CD, and 13C NMR spectra. The meso–racemic isomerization, which results from the cleavage of the Co–S bonds, was recognized for [Co{Ir(aet)3}2]3+ in D2O, methanol–H2O, and ethanol–H2O. The cyclic voltammogram of rac-[Co{Ir(aet)3}2]3+ in water showed two almost reversible redox couples at −0.23 V and +0.73 V (vs. Ag/AgCl). The chemical properties of the present IrIIICoIIIIrIII complexes are discussed in comparison with those of the corresponding RhIIICoIIIRhIII and CoIIICoIIICoIII complexes.

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)

“…Each of the voltammograms displays a quasi-reversible redox couple in the negative potential region. In analogy to the characterized electrochemistry of the [Co{M(aet) 3 [33,[39][40][41] this redox process is assigned as the redox couple corresponding to Co III/II . The redox couples of the apt complexes 2a (-0.56 V) and 2b (-0.57 V) are more negative than those of the aet complexes 4a (-0.35 V) and 4b (-0.36 V).…”

“…The redox couples of the apt complexes 2a (-0.56 V) and 2b (-0.57 V) are more negative than those of the aet complexes 4a (-0.35 V) and 4b (-0.36 V). [33,39] This means that the Co III state in apt complexes is more stable than that in 4a and 4b. A possible reason for this might be the difference in nucleophilicity of sulfur or structural differences of the Co III ion resulting from the additional methylene group in apt, which forms six-membered chelates rather than fivemembered ones, as is the case for aet.…”

Heterometallation of Photoluminescent Silver(I) Sulfide Nanoclusters Protected by Octahedral Iridium(III) Thiolates

“…Unfortunately, the Rh III 14 Ag I 46 and Rh III 14 Ag I 43 Cu I 3 clusters were almost non‐emissive due to the low‐lying d‐d excited state of the Rh III center [16] . In this work, we employed fac ‐[Ir(aet) 3 ] [17] as the protecting metalloligand instead of fac ‐[Rh(aet) 3 ] for the synthesis of an analogous sulfide cluster. Since the d‐d transition energy of fac ‐[Ir(aet) 3 ] is much higher than the energy of fac ‐[Rh(aet) 3 ], [17] we expected that the generated cluster would show some intriguing photoluminescent performance.…”

“…In this work, we employed fac ‐[Ir(aet) 3 ] [17] as the protecting metalloligand instead of fac ‐[Rh(aet) 3 ] for the synthesis of an analogous sulfide cluster. Since the d‐d transition energy of fac ‐[Ir(aet) 3 ] is much higher than the energy of fac ‐[Rh(aet) 3 ], [17] we expected that the generated cluster would show some intriguing photoluminescent performance. Herein, we report that a similar reaction using fac ‐[Ir(aet) 3 ] indeed gives the analogous Ir III 14 Ag I 46 sulfide nanocluster, [Ag 46 S 13 {Ir(aet) 3 } 14 ] 20+ ([ 1 ] 20+ ), which is photoluminescent.…”

Controlled Formation of Thiol‐Thiolate Hydrogen versus Disulfide Bonds between Two Iridium(III) Centers

“…Previously,w er eported that treatment of fac-[Rh(aet) 3 ] (aet = 2-aminoethanethiolate) with aqueous HBF 4 under aerobic conditions leads to the formation of the dimerics tructure in [Rh 2 (aet) 3 (Haet) 3 ] 3 + ([2 Rh ] 3 + )h aving at riple S-H···S hydrogen bond between two Rh III centers. [12] On the other hand, similar treatment of fac-[Ir(aet) 3 ] [13] with aqueous HNO 3 or HCl under aerobic conditions wasa ccompaniedb yt he air oxidation of thiolatog roups to form the dinuclear structure in [Ir 2 (aet) 4 (cysta)] 2 + ([1] 2 + ;c ysta = cystamine) having as ingle S-S disulfideb ond between two Ir III centers. [14] In this work, we investigated the reactiono ffac-[Ir(aet) 3 ]w ith acid in more detail to determine reaction conditions that afford iridium(III) species bearing SÀH···S hydrogen bonds.…”