Light-Induced Absorption in Bismuth Titanium Oxide Crystals Illuminated with Narrow-Band Light

Results of investigations into the dynamics of light-induced absorption in bismuth titanium oxide crystals doped with calcium (Bi₁₂TiO₂₀:Ca) illuminated with quasimonochromatic light of semiconductor light-emitting diodes at two wavelengths from the set = 870, 660, and 525 nm are presented. Based on an analysis of the experimental data, a model of charge transfer by defect centers describing the observed phenomena is suggested.     

Umsetzungen von Allyldichlorphosphit und Allyldifluorphosphit mit einigen Verbindungen von Übergangsmetallen; Darstellung und spektroskopische Untersuchung von Allyldichlor- bzw. Allyldifluorphosphit-Carbonyl-Metall(0)-Koordinationsverbindungen (MetallCr,Mo, W,Fe)

Reactions of Allyldichlorophosphite and Allyldifluorophosphite with some Transition Metal Compounds; Synthesis and Spectroscopic Identification of Allyldichloro- and Allyldifluorophosphite-Carbonyl-Metal(0) Coordination Compounds (Metal?Cr, Mo, W, Fe) In the reactions of allyldifluorophosphite ( 1 ) and allyldichlorophosphite ( 2 ) with the carbonyl compounds (C₇H₈)M(CO)₃ (M?Cr, Mo; C₇H₈ ? cycloheptatriene), W(CO)₅THF (THF = tetrahydrofuran), Fe(CO)₅ or Fe₂(CO)₉ the allyldichloro- and allyldifluorophosphite-carbonyl-metal compounds fac-(AllOPF₂)₃Cr(CO)₃ 3 a , mer-(AllOPF₂)₃Cr(CO)₃ 3 b , fac-(AllOPF₂)₃Mo(CO)₃ 4 , fac-(AllOPCl₂)₃Mo(CO)₃ 5 , (AllOPF₂)W(CO)₅ 6 , (AllOPCl₂)W(CO)₅ 7 , (AllOPF₂)Fe(CO)₄ 8 and (AllOPCl₂)Fe(CO)₄ 9 were formed (All = CH₂?CHCH₂). In 8 and 9 the ligands 1 or 2 are axially orientated. The validity of the concept of hard and soft acids and bases (HSAB-concept) and of the 18-valency electron rule (18-VE-rule) was confirmed. The allyl dihalophosphites 1 and 2 coordinate via phosphorus. The allylic π-system was not involved in the coordinative bond. The characterization of the coordination compounds 3 , 4 , 5 a , 5 b und 6 ? 9 was based on their IR and NMR spectra, and on the mass spectra.     

Umsetzungen einiger Schwefel-Fluor-Verbindungen mit Verbindungen von übergangsmetallen; Darstellung und spektroskopische Untersuchung von Sulfito-Komplexen mit MnII,Mo0 und W0

Reactions of some Sulfur-Fluorine Compounds with Compounds of Transition Metals; Synthesis and Spectroscopic Investigation of Sulfito Complexes, involving Mn^II, Mo⁰, and W⁰ In the oxidative addition reactions of sulfuryl fluoride ( 1 ) and of methanesulphonic acid fluoride ( 2 ) with η²-ethylene-bis(triphenylphosphine)platinum(0) the novel ionic binuclear tetrakis(triphenylphosphine)-(μ-fluoro)-(μ-peroxo)-platinum(II)-fluorosulfonate and -methylsulfonate complexes 3 a and 3 b were formed. O,O-Sulfito-manganese(II) tricarbonyl 5 a and the binuclear μ-disulfito-dimanganese decacarbonyl complex 6 a were obtained in the reaction of disulfuryl difluoride ( 4 ) with the carbonyl metalate complex, Na⁺[Mn(CO)₅]^?. In this redox reaction several further products (e.g., CO, SO₂F₂ ( 1 ) and Mn₂(CO)₁₀) were formed and were determined quantitatively. In the presence of acetonitrile the acetonitrile-O,O-sulfito-manganese(II) tricarbonyl complex 5 b was isolated. The new binuclear complexes, bis(η⁵-cyclopentadienyl)-μ-disulfito-dimetalhexacarbonyls ( 6 b : metal = Mo⁰ and 6 c : metal = W⁰) were obtained in the reaction of 4 with the carbonyl metalates Na⁺[CpM(CO)₃]^? (M?Mo¹, W¹; Cp = cyclopentadienyl). Further products (e.g., CO, SO₂F₂ ( 1 ) and [CpM(CO)₃]₂, M?Mo, W) were formed and were determined quantitatively. The validity of the concept of hard and soft acids and bases (HSAB-concept) and of the 18-valence-electron rule (18-VE-rule) could not be confirmed in all cases. The characterization of 3a, 3b, Sb, 6b and 6c was based on their IR and NMR spectra, and in one case, on the mass spectra ( 5b ). For 3a and 3b the dynamic behaviour at room temperature in CD₂Cl₂ and CD₃OD was studied by ³¹P-NMR spectroscopy. The results are interpreted in terms of exchange processes in solution between the coordinated μ-fluoride and the solvent ligand or the uncoordinated anion. 5a and 6a and the by-products (e.g., CO and SO₂F₂ ( l )), which were formed in the redox reactions, were identified by their infrared spectra.