80946-83-4Relevant academic research and scientific papers
The X-ray crystal structures of double salts of hexahalorhodate(III) and halide with the ethane-1,2-diammonium cation
Gillard,Hibbs, David E.,Holland, Carolyn,Hursthouse, Michael B.,Malik, K. M. Abdul,Sykara, Georgia
, p. 225 - 232 (2008/10/08)
The compounds precipitated on adding 1,2-diaminoethane (en) to hexachlororhodate(III) and hexabromorhodate(III) solutions in hydrochloric and hydrobromic acids, although classically described as anhydrous, are actually the hydrated [enH2]2[RhCl6][Cl] · H2O and [enH2]2[RhBr6][Br] ?H2O. The X-ray crystal structures of both compounds are reported. In each case, the cations adopt a trans conformation and the complex anion closely approximates to Oh symmetry. However, the crystals are not isostructural, but closely related. The c axis of the chloride is approximately double that of the bromide. Some spectroscopic and chemical properties of the double salts are given.
Aqueous solution photophysics and photochemistry of dihalo- and aquahalobis(ethylenediamine)rhodium(III). Effect of nonreacting amine ligands on excited-state halide dissociation and excited-state rearrangement
Skibsted,Hancock,Magde,Sexton
, p. 1708 - 1712 (2008/10/08)
Ligand field excitation of cis- and trans-[Rh(en)2X2]+ (X = Cl, Br) in acidic aqueous solution leads to halide photoaquation producing [Rh(en)2(H2O)X]2+. Room-temperature phosphorescence lifetimes of the four dihalo complexes in aqueous solution were measured by using a mode-locked laser and time-correlated single-photon detection and found to be about 2 ns in each case. Excited-state halide dissociation and nonradiative deactivation rate constants were evaluated from a combination of the lifetimes and the photoaquation quantum yields. The halide dissociation rate constants range from 1.9 × 108 (cis-dichloro) to 2.1 × 107 s-1 (trans-dibromo) and are in all cases smaller (by a factor of 1.6-15) than the rate constants previously determined for the tetraammine and bis(1,3-propanediamine) analogues. Also described are the syntheses of the dithionate salts of trans- and cis-[Rh(en)2(H2O)X]2+, and quantum yields for the cis/trans interconversion of each isomeric pair in aqueous solution at 25°C are given.
