Hydrolytic polymerization of rhodium(III). 1. Preparation, solution studies, and x-ray structure of the doubly bridged dimer [(H2O)4Rh(.mu.-OH)2Rh(OH2)4](dmtos)4.cntdot.8H2O

Self-Assembled Superanions: Ionic Capsules Stabilized by Polynuclear Chromium(III) Aqua Cations

“…[29] Although studies of the hydrolytic polymerisation of Cr 3 and Rh 3 has led to the isolation and solution characterisation of several oligomers, [22,23] attempts to crystallize oligomers with a higher nuclearity than dinuclear species have been unsuccessful. The superanion or ionic capsule approach demonstrates a new general method for the structural characterisation of metal ions present in aqueous systems.…”

“…Indeed this has led to the structural authentication of the nonlabile polynuclear hydrolytic Cr III cations [Cr 3 (OH) 4 6 for the first time. [22] The only previously characterised species in the series is the lowest oligomer, the dinuclear cation [Cr 2 (OH) 2 (H 2 O) 8 ] 4 ; the anaologous nonlabile, dinuclear Rh III [23] and mixed Cr III and Rh III species are the only authenticated cations in their respective homologous series. [24] Furthermore, the superanion has been found to selectively bind the cations according to size and shape.…”

Supramolecular Complexation of Polynuclear Aqua Ions: A Crown Ether Adduct of aμ-Oxo-Bridged Iron(III) Aqua Dimer

“…Previous X-ray structural studies on binuclear aqua ions of Al III , [6] Cr III , [7] Sc III , [8] and Rh III , [9] as well as on a heterometallic Cr III Rh III aqua ion, [10] showed that the bis(m-hydroxo)M 2 core is preferred in all these cases. However, the existence of a moxo-bridged Cr III dimer was proposed on spectroscopic grounds.…”

Elucidation of Metal‐Ion Accumulation Induced by Hydrogen Bonds on Protein Surfaces by Using Porous Lysozyme Crystals Containing RhIIIIons as the Model Surfaces

“…The bond lengths of Rh1 À Rh2, Rh2 À Rh3, and Rh1 À Rh3 are 3.35, 2.99, and 1.57 , respectively. Although O2 serves as a bridging ligand and is located 2.10, 2.48, and 1.87 away from Rh1, Rh2, and Rh3, respectively, [49,50] a trinuclear structure is apparently not formed at this site because the 1.57 bond length between Rh1 À Rh3 is too short to stabilize the trinuclear geometry. This is also supported by the low occupancies of the Rh1 (0.4) and Rh3 (0.6) atoms.…”

“…An oxygen atom (O3) serves as a bridging ligand with Rh4 À O3 and Rh5 À O3 bond lengths of 2.22 and 2.16 , respectively. [49] The short length of the Rh4À Rh5 bond (2.76 ) also suggests the existence of a OHbridged dinuclear structure. [49] Binding Site C: It is known that Asn46 and Asp52 can bind metal ions such as Co II , Ni II , Gd III , and Yb III with different coordination geometries.…”