Photochemistry of the cyanopentaamminechromium(III) ion

Stereochemistry of equatorial aquation in the ligand field photolysis of trans-dicyanotetraamminechromium(III)

“…Moreover, both products have a meridional configuration; i.e., the missing species is the "m-dicyano" one of facial type. These findings supplement previous reports of partial stereorearrangement for in-plane photosubstitution of CrN5F2+8•22 and trans-Cr(en)2F2+ ions18 and help one to understand the stereochemical behavior of Cr(NH3)5(CN)2+ 32 (vide infra). It is worthwhile to note that the procedure adopted for stereochemical identification would be hardly possible starting from the analogous ethylenediamine complex.…”

Photoreactions of rhodium(III) complexes: the cyanoammines Rh(NH3)5CN2+ and trans-Rh(NH3)4(H2O)CN2+

“…In this context, it is notable that 7*(M-L) values calculated for fra/i$-Rh(NH3)4(H20)CN2+ suggest the Rh-H20 bond to be by far the most susceptible to labilization in the 3E state but to have a somewhat larger /*(M-L) value than that for Rh-NH3 bond for the 3A2 state.25,26 For both excited-state configurations, 7*(Rh-CN) is clearly not the weakest for iranj-Rh(NH3)4(H20)CN2+ or Rh(NH3)5CN2+, consistent with the failure to observe any CN" photoaquation in either case. This behavior is similar to earlier reports of exclusive NH3 photoaquation from Cr(NH3)5CN2+ 27 and exclusive Cl" photoaquation from frans-Co(en)2ClCN+ 28 but contrasts with the observation of both NH3 and CN" photo-aquation (the former the more predominant) for Co-(NH3)5CN2+. 29 The latter result may reflect the role of reactions from upper excited states in cobalt(III) amine complex photochemistry.36…”

Homogeneous photocatalysis by transition metal complexes in the environment

“…The photoredox reaction is characterized by an unusual pathway: the oxidation of Cr(III) to Cr(VI) is initiated by its photoreduction to Cr(II). The Cr(III) → Cr(II) path was observed in a number of Cr(III) complexes, such as: [Cr(CN) 6 ] 3− , [Cr(CN) 5 [192,193,197,198], [Cr(CN) 5 [200][201][202][203], [trans-Cr(NH 3 ) 4 (NCS(CN))] + [204].…”