Pentaammineruthenium(III) complexes of neutral and anionic (2,3-dichlorophenyl)cyanamide: a spectroscopic analysis of ligand to metal charge-transfer spectra

Abstract

General synthetic methods are presented for neutral and anionic phenylcyanamide ligands and their pentaammineruthenium(III) complexes. A spectroscopic analysis of the complexes, in microsymmetry, details the origin of the ligand to metal charge-transfer bands observed in aqueous solution. For [Ru(NH3)5(2,3-Cl2Hpcyd)]3+, the LMCT band at 487 nm is assigned to an allowed b2* b2 transition. For [Ru(NH3)5Ru(2,3-Cl2pcyd)]2+, the LMCT transitions at 356 and 629 nm are assigned to forbidden b3* <-b2 and allowed b,* •*b, transitions, respectively.

Solar Irradiation Induced Transformation of Ferrihydrite in the Presence of Aqueous Fe2+

“…After 12 h of reaction, the concentration of ferrihydrite under UV irradiation (71.8 mg L –1 ) was lower than that under dark conditions (75.9 mg L –1 ), indicating that UV irradiation promotes the transformation of ferrihydrite to goethite and lepidocrocite. During the photochemical oxidation of As­(III) and Sb­(III) by ferrihydrite, As­(III) and Sb­(III) can form complexes with ferrihydrite, and electrons are transferred from As­(III) and Sb­(III) to Fe­(III) in ferrihydrite through the LMCT process. , The ligand-to-metal electron transfer in the LMCT process can be indicated by UV–vis absorption spectra. , Fe 2+ aq can be adsorbed on the ferrihydrite surface to form a Fe­(II)–ferrihydrite complex . The UV–vis absorption spectra of the ferrihydrite suspension at pH 6.0 were collected to analyze the role of the Fe­(II)–ferrihydrite complex in the oxidation of Fe 2+ aq (Figure ).…”

“…16,19 The ligand-to-metal electron transfer in the LMCT process can be indicated by UV−vis absorption spectra. 43,44 Fe 2+ aq can be adsorbed on the ferrihydrite surface to form a Fe(II)−ferrihydrite complex. 45 The UV−vis absorption spectra of the ferrihydrite suspension at pH 6.0 were collected to analyze the role of the Fe(II)−ferrihydrite complex in the oxidation of Fe 2+ aq (Figure 3).…”

Influence of the Inner Coordination Sphere on the Ru(III)−Cyanamido Ligand-to-Metal Charge Transfer Chromophore

“…Tetrabutylammonium hexafluorophosphate (TBAH) was purchased from Aldrich and recrystallized twice from ethanol/water and then vacuum-dried at 110 °C. Syntheses of [Ru(bpy)(trpy)Cl][PF 6 ] 5 and the thallium salts of phenylcyanamide ligands (pcyd - ) have been previously described …”

Mechanisms of UV-Light Promoted Removal of As(V) by Sulfide from Strongly Acidic Wastewater

“…If a charge-transfer process occurs in the H 3 AsO 3 S complex, then a charge-transfer spectrum should be observed by UV−vis spectroscopy because electrons are transferred from S(-II) to As(V) in the H 3 AsO 3 S complex. 45,46 In our experiment, the spectra of H 3 AsO 4 , H 2 S, and the H 3 AsO 3 S complex were obtained by UV−vis spectroscopy at various As(V)/S(-II) ratios. Both 1.33 mM H 3 AsO 4 and 1 mM H 2 S showed negligible absorptions at wavelengths near 233 nm.…”