Photolysis of cis- and trans-dicyanobis(ethylenediamine)chromium(III) ions

Photochemistry and Photophysics of Chromium(III) Complexes

“…To interpret it as a prompt reaction from the FC states (a DOSENCO process 5 ) raises the question of why it would be so specific to ethylenediamine loss. Reaction via 4 B 2 and 4 E states has similarly been used to rationalize 24,224,225 the wavelength dependence of the am(m)ine and cyanide photoaquation modes in several cyanoam(m)ine complexes. There is further support for this two-quartetstate photochemical model from wavelength-and temperature-dependence studies 226,227 An interesting feature of that part of the photoreaction that proceeds via the doublet is that its reaction mode ratio and stereochemistry is the same as that for the quartet-state reaction seen for longwavelength irradiation.…”

Effects of Steric Constraint on Chromium(III) Complexes of Tetraazamacrocycles. 3. Insights into the Temperature-Dependent Radiationless Deactivation of the 2Eg (Oh) Excited State of trans-[Cr(N4)(CN)2]+ Complexes

“…In that paper, the only mechanism that was not ruled out was the photodissociation of a macrocyclic N−Cr bond followed by rapid recoordination. The feasibility of this mechanism is supported by the fact that nonmacrocyclic trans -[Cr(N 4 )(CN) 2 ] + complexes undergo substantial loss of the amine ligands upon photolysis. − In fact, this in-plane amine ligand loss is the predominant pathway for the photodecomposition of these complexes. If such N labilization occurs with the macrocyclic ligands, the most likely result would be rapid recoordination due to the macrocyclic effect.…”

Coordination modes of polydentate ligands. 3. Five-coordinate complexes of cobalt(2+), copper(2+), and nickel(2+) containing a tridentate thioether-alkoxy ligand

“…The solution was filtered and solvent removed by rotary evaporation; then the residue was extracted with CH2C12 and the solution filtered and evaporated. The resulting solid (5), purple crystals from ethanol; Co(0-S-0)(py)2 (6), purple crystals from ethanol containing ~1% pyridine; Co(0-S-0)(bpy) (7), green crystals from dichloromethane; Ni(O-S-O) (TMED) (8), olive green crystals from ethanol; Ni(0-S-0)(py)2 (9) olive green crystals from benzene/ hexane; Cu(Ó-S-0)(TMED) (10), blue crystals from ethanol; Cu(0-S-0)(py)2 (11), blue crystals from ethanol containing ~1% pyridine; Cu(0-S-0)(bpy) (12), blue crystals from dichloromethane/hexane.…”