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

Abstract

The reduction of a variety of Co(III) complexes and molecular oxygen has been observed upon irradiating [Cu-(dmp)2]+ in solution. The results are consistent with the idea that a strongly reducing CT excited state of [Cu(dmp)2] +

Photochemistry and Photophysics of Chromium(III) Complexes

“…The importance of these complexes is that, cyanide being a stronger-field ligand than am(m)ine, the lowest excited state in most of the trans-Cr(N) 4 (CN)Y + isomers is the 4 B 2 state for which the AOM predicts labilization of the ligand(s) in the equatorial plane. Cr(NH 3 ) 5 CN 2+ and trans-Cr(NH 3 ) 4 (CN) 2 + fit the expectations nicely by photoaquating 93 Some mixed aquacyano complexes have also been included in Table 2. No water exchange yields have been measured for these species, which are often difficult to study because of concurrent thermal reactions.…”

“…88 Some parallels with this behavior can be found in mixed cyanoam(m)ine complexes. Cyano complexes have been extensively studied [90][91][92][93][94][95][96][97][98][99][100] by the Perugia group of Riccieri and Zinato and co-workers. Zinato has written an excellent review 24 of their synthesis, properties, spectroscopy, thermal kinetics, photochemistry, and photophysics.…”

“…These studies also gave 157 the values 0.74 for Cr(NH 3 ) 5 (CN) 2+ in agreement with the 0.73 value 95 from quenching experiments, 0.77 for Cr(NH 3 ) 5 -(NCS) 2+ , 1.0 for trans-Cr(en) 2 F 2 + , and >0. 93 for Cr(bpy) 3 3+ . Absorption monitoring of Cr(en) 3 3+ photoproducts 155 gave a value of 0.70 for the fraction of reaction occurring via the doublet, although the authors concluded that η isc ) 0.3.…”

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.…”

Organometallic Compounds of Chromium, Molybdenum and Tungsten without Carbonyl Ligands

“…The corresponding dark reaction results in exclusive CN" loss. 176 Aquation proceeds in two successive steps and each stage may be described by an acid-independent path and an acid-dependent path. 177 The photochemistry of f raws-[Cr(CN) 2 (cy clam)] [ C 1 O 4 ] is quite different.…”