Intramolecular Site Exchange of Carbonyl Ligands in the Cluster Compounds Nonacarbonyl{μ3-[η3-(1,3,5-trithiane)]}triruthenium ([Ru3(CO)9{μ3-(η3-C3H6S3)}]) and (tert-Butyl Isocyanide)octacarbonyl-{μ3-[η3-(1,3,5-trithiane)]}triruthenium ([Ru3(t-BuNC)(CO)8{μ3-(η3-C3H6S3)}])

Variable-temperature and -pressure ¹³C-NMR studies of the 1,3,5-trithiane-capped triruthenium clusters [Ru₃(CO)₉{μ₃-(η³-1,3,5-trithiane)}] ( 1 ) and [Ru₃(t-BuNC)(CO)₈{μ₃-(η³-1,3,5-trithiane)}] ( 2 ) revealed that CO site exchanges occur via an intramolecular merry-go-round process, involving a transition state mostly dissociative in character.     

Schwingungsspektroskopische Untersuchungen an Trimethylphosphonium-Kationen (CH3)3PX+ (X = H,D) und Kristallstrukturen von (CH3)3PD+SbCl6− und (CH3)3PCl+SbCl6−

Vibrational Spectra of Trimethylphosphonium Cations (CH₃)₃PX⁺ (X = H, D) and Crystal Structures of (CH₃)₃PD⁺SbCl₆^? and (CH₃)₃PCl⁺SbCl₆^? The trimethylphosphonium salts (CH₃)₃PX⁺SbCl₆^? (X = H, D) and (CH₃)₃PH⁺MF₆^? (M = As, Sb) are prepared and characterized by vibrational and NMR spectroscopy (¹H, ³¹P, ¹³C). In addition the crystal structures of (CH₃)₃PD⁺SbCl₆^? and (CH₃)₃PCl⁺SbCl₆^? are reported. (CH₃)₃PD⁺SbCl₆^? crystallizes in the orthorhombic space group Pnma with a = 1555(1) pm, b = 753.1(8) pm, c = 1166(1) pm Z = 4. (CH₃)₃PCl⁺SbCl₆^? crystallizes triclinic in the space group P1 with a = 704.6(4) pm, b = 729.5(3) pm, c = 1391.1(7) pm, α = 89.57(4)°, b? = 88.04(4)°, γ = 74.98(4)° and Z = 2.     

Chelating and Tellurolate Ligand‐Transfer Studies of the Complex fac‐[Fe(CO)3(TePh)3]−: Crystal Structures of Heterodinuclear (CO)3Mn(μ‐TePh)3Fe(CO)3 and CpNi(TePh)(PPh3)

Complex fac‐[Fe(CO)₃(TePh)₃]^? was employed as a “metallo chelating” ligand to synthesize the neutral (CO)₃Mn(μ‐TePh)₃Fe(CO)₃ obtained in a one‐step synthesis by treating fac‐[Fe(CO)₃(TePh)₃]^? with fac‐[Mn‐(CO)₃(CH₃CN)₃]⁺. It seems reasonable to conclude that the d⁶ Fe(II) [(CO)₃Fe(TePh)₃]^? fragment is isolobal with the d⁶ Mn(I) [(CO)₃Mn(TePh)₃]^2? fragment in complex (CO)₃Mn(μ‐TePh)₃Fe(CO)₃. Addition of fac‐[Fe(CO)₃(TePh)₃]^? to the CpNi(I)(PPh₃) in THF resulted in formation of the neutral CpNi(TePh)(PPh₃) also obtained from reaction of CpNi(I)(PPh₃) and [Na][TePh] in MeOH. This investigation shows that fac‐[Fe(CO)₃(TePh)₃]^? serves as a tridentate metallo ligand and tellurolate ligand‐transfer reagent. The study also indicated that the fac‐[Fe(CO)₃(SePh)₃]^? may serve as a better tridentate metallo ligand and chalcogenolate ligand‐transfer reagent than fac‐[Fe(CO)₃(TePh)₃]^? in the syntheses of heterometallic chalcogenolate complexes.     

Cluster chemistry: XXXIX. Gold—ruthenium clusters with sulphur ligands: Synthesis and structure of HRu3Au(μ3-S)(CO)9(PPh3), Ru3Au(μ3-SBut)(CO)9(PPh3) and Ru3Au2(μ3-S)(CO)9(PPh3)2

H₂Ru₃(μ₃-S)(CO)₉ is deprotonated by K[HBBu^s₃] to give cluster anions which react with [O{Au(PPh₃)}₃]⁺ or with AuCl(PPh₃)/T1⁺ to give HRu₃Au(μ₃-S)(CO)₉(PPh₃) (1) and Ru₃Au₂(μ₃-S)(CO)₉(PPh₃)₂ (3). A similar sequence with HRu₃(μ₃-SBu^t)(CO)₉ leads to Ru₃Au(μ₃-SBu^t)(CO)₉(PPh₃) (2) as the main product although some 1 also forms, indicating SC cleavage competes with deprotonation of HRu₃(μ₃-SBu^t)(CO)₉ by [HBBu^s₃]^?. The X-ray crystal structures of 1, 2 and 3 are described; (1) and (2) have “butterfly” AuRu₃ cores with markedly different hinge angles of 119 and 148° respectively, while 3 has a trigonal-bipyramidal Au₂Ru₃ skeleton. All three clusters have the sulphur atom symmetrically bridging the Ru₃ triangular face.     

Bi3+-Er3+ and Bi3+-Yb3+ Codoped Cs2AgInCl6 Double Perovskite Near-Infrared Emitters

Bi³⁺ and lanthanide ions have been codoped in metal oxides as optical sensitizers and emitters. But such codoping is not known in typical semiconductors such as Si, GaAs, and CdSe. Metal halide perovskite with coordination number 6 provides an opportunity to codope Bi³⁺ and lanthanide ions. Codoping of Bi³⁺ and Ln³⁺ (Ln=Er and Yb) in Cs₂AgInCl₆ double perovskite is presented. Bi³⁺-Er³⁺ codoped Cs₂AgInCl₆ shows Er³⁺ f-electron emission at 1540 nm (suitable for low-loss optical communication). Bi³⁺ codoping decreases the excitation (absorption) energy, such that the samples can be excited with ca. 370 nm light. At that excitation, Bi³⁺-Er³⁺ codoped Cs₂AgInCl₆ shows ca. 45 times higher emission intensity compared to the Er³⁺ doped Cs₂AgInCl₆. Similar results are also observed in Bi³⁺-Yb³⁺ codoped sample emitting at 994 nm. A combination of temperature-dependent (5.7 K to 423 K) photoluminescence and calculations is used to understand the optical sensitization and emission processes.     

An Improved Preparation of Polymer-Type η3-Allylpalladiumchlorides

Five polymer-type new compounds-(η³-cyclopentadienyl)palladiumchloride ( 6 ), (η³-indenyl) palladiumchloride ( 7 ), (η³-cycloheptatrienyl)palladiumchloride ( 8 ), (η³-phenalenyl)palladiumchloride ( 9 ) and (1,2,3-η³-4,5,6,7-η⁴-cyclopheptatrienyl)(palladium-chloride)(tricarboryl Iron) ( 10 ) have been prepared from the reaction of Na₂PdCl₄ with 1-trimethylsilylcyclopentadiene ( 1 ), 1-trimethylsilylindene ( 2 ), 1-trimethylsilyl cycloheptatriene ( 3 ), 1-trimethylsilylphenalene ( 4 ) and 1-trimethylsilylcycloheptatriene tricarbonyl Iron ( 5 ) respectively. All the complexes( 6 )-(10) are obtained in excellent yield using the improved preparation route. Furthermore, a reaction mechanism is proposed.     

Zwei Fluoridborate des Gadoliniums: Gd2F3[BO3] und Gd3F3[BO3]2

Two Fluoride Borates of Gadolinium: Gd₂F₃[BO₃] and Gd₃F₃[BO₃]₂ By flux‐supported solid‐state reaction of Gd₂O₃ and GdF₃ with B₂O₃ (flux: CsCl, molar ratio: 1 : 1 : 1 : 6, sealed tantalum capsule, 700 °C, 7 d) the new gadolinium fluoride borate Gd₂F₃[BO₃] (monoclinic, P2₁/c; a = 1637.2(1), b = 624.78(4), c = 838.04(6) pm, β = 93.341(8)°; V_m = 64.418(6) cm³/mol, Z = 8) was obtained as colourless, prismatic, face‐rich single crystals. The four crystallographically different Gd³⁺ cations (CN = 9) are all capped square‐antiprismatically surrounded by fluoride and oxide anions, in which the latter represent always components of isolated trigonal planar [BO₃]^3— anions. The six crystallographically independent F^— anions all reside in more or less planar coordination of three Gd³⁺ cations. Thus the constitution of Gd₂F₃[BO₃] can be described as a sequence of alternating layers each of the composition Gd[BO₃] and GdF₃ parallel (100), respectively. The crystal structures of Gd₂F₃[BO₃] and the shortly published Gd₃F₃[BO₃]₂ (monoclinic, C2/c; a = 1253.4(1), b = 623.7(1), c = 836.0(1) pm, β = 97.404(6)°; V_m = 97.571(9) cm³/mol, Z = 4) are compared with each other. Due to the structural analogies between these two gadolinium fluoride borates, a disorder model of the boron atoms frequently found for Gd₂F₃[BO₃] is able to be transferred to Gd₃F₃[BO₃]₂ as well.     

A novel Sr3Y(PO4)3-based white light-emitting phosphor

The Sr₃Y(PO₄)₃:0.05Sm³⁺, Sr₃Y(PO₄)₃:0.005Tb³⁺, and Sr₃Y(PO₄)₃:0.005Tb³⁺, 0.05Sm³⁺ phosphors were synthesized using a conventional solid-state reaction technique at high temperature and their photoluminescence properties under ultraviolet (UV) excitation were studied. We observed the UV sensitization of Sm³⁺ emission (565, 600, and 648 nm) by Tb³⁺ in Sr₃Y(PO₄)₃:0.005Tb³⁺, 0.05Sm³⁺, that leads to a white light emission with the CIE coordinate (0.367, 0.312) of Sr₃Y(PO₄)₃:0.005Tb³⁺, 0.05Sm³⁺ phosphor under UV excitation. The emission is a result of partial energy transfer from Tb³⁺ to Sm³⁺, which is discussed in detail in terms of the corresponding excitation and emission spectra.     

Synthesis and crystal structure of an ionic cluster {[Mo_3(μ_3-O)(μ-S)_3(dtp)_3(py)_3][CdI(dtp)_2]}

A new cluster compound {[Mo3(μ3-O)(μ-S)3(dtp)3(py)3][CdI(dtp)2]} (dtp=S2P(O-was obtained from the reaction of (Mo3OS3(dtp)4(H2O)] with a CdI2-Bu4NI mixture.The molecular structure is composed of a cluster cation [Mo3OS3(dtp)3(py)3]+ and the complex anion [CdI(dtp)2]-Crystal data:Triclinic,space group P1 with cell parameters a=1.4672(7),b=1.5356(5),c=1.6806(5) nm,α=74.59(3),β=67.89(4),7=78.86(3)°,V=3.364(2) nm3,and Z=2,least-squares refinement of 8941 reflections gives a final agreement factor of R=0.052,Rw=0.065.     

Kinetic study of the reaction of IO with CH3SCH3

The reaction IO + CH₃SCH₃ → products (3) was studied at room temperature and near 1 Torr pressure of He, using the discharge flow mass spectrometric technique. The rate constant was found to be k₃ = (1.5 ± 0.5) × 10^?11 cm³ molecule^?1 s^?1. CH₃S(O)CH₃ was detected as a product suggesting the following channel: IO + CH₃SCH₃ → CH₃S(O)CH₃ + I. The rate constant of the reaction IO + IO → products (1) was also measured: k₁ = (3 ± 0.5) × 10^?11 at 298 K and 1 Torr pressure. The atmospheric implication of reaction (3) is discussed. The results indicate that this reaction could be a potential important sink of CH₃SCH₃ in marine atmosphere.     

Die Kristallstruktur von [InI · C6D6][{(CH3)3Si}3C‐InI3]; ein Nebenprodukt der Umsetzung von InI3 mit basefreiem Li‐C(Si(CH3)3)3

The title compound is formed together with Li[Tsi‐InI₃] (the main product), (Tsi‐In(Me)I)₂ and (Tsi)₂InMe in very low yield in the reaction of InI₃ with Tsi‐Li (Tsi = ‐C(Si(CH₃)₃)₃)in toluene. According to the X‐ray structure determination this compound crystallizes in the triclinic space group P&1marc; and consists of slightly associated dimers of [Tsi‐InI₃]^‐ anions via weak In^I···I(‐In^III) contact‐bonds of 345.6(1) to 373.8(2) pm. Additionally the In^I atom is capped by a D₆‐benzene molecule.     

Intercombination decay of 3s3p 3 P 1 0 in MgI-like Ni and Cu

The intercombination transition 3s^{2 1}S₀ ?3s3p³P ₁ ⁰ in Ni¹⁶⁺ and Cu¹⁷⁺ has been studied by beam-foil spectroscopic methods. Decay curve analysis yields lifetime values of (12.0±1.0)ns and (8.8±0.6)ns for Ni and Cu in agreement with various predictions.     

[Ge9{Si(SiMe3)3}2{Ge(SiMe3)3}]–: The Mixed Substituted Metalloid Germanium Cluster and the Intermetalloid Cluster [ZnGe18{Si(SiMe3)3}4{Ge(SiMe3)3}2]

The novel metalloid germanium cluster [Ge₉(Hyp)₂Hyp^Ge]^– ( 1 ) was synthesized, exhibiting two different bulky groups [Hyp = Si(SiMe₃)₃; Hyp^Ge = Ge(SiMe₃)₃]. Further reaction of 1 with ZnCl₂ gives the derivative [ZnGe₁₈(Hyp)₄(Hyp^Ge)₂] ( 2 ) in good yield, showing that the substitution of Si(SiMe₃)₃ by Ge(SiMe₃)₃ within a metalloid Ge₉R₃^– compound leads to a comparable reactivity. 1 and 2 are characterized by NMR spectroscopy, mass spectrometry ( 1 ) and single crystal structure analyses ( 2 ). 1 and 2 are the first metalloid germanium clusters bearing germyl groups.     

Syntheses and Crystal Structures of BaAgTbS3, BaCuGdTe3, BaCuTbTe3, BaAgTbTe3, and CsAgUTe3

Five new quaternary chalcogenides of the 1113 family, namely BaAgTbS₃, BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and CsAgUTe₃, were synthesized by the reactions of the elements at 1173–1273 K. For CsAgUTe₃ CsCl flux was used. Their crystal structures were determined by single‐crystal X‐ray diffraction studies. The sulfide BaAgTbS₃ crystallizes in the BaAgErS₃ structure type in the monoclinic space group C³,_2h‐C2/m, whereas the tellurides BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and CsAgUTe₃ crystallize in the KCuZrS₃ structure type in the orthorhombic space group D¹_,2⁷_,h‐Cmcm. The BaAgTbS₃ structure consists of edge‐sharing [TbS₆^9–] octahedra and [AgS₅^9–] trigonal pyramids. The connectivity of these polyhedra creates channels that are occupied by Ba atoms. The telluride structure features ²_∞[MLnTe₃^2–] layers for BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and ²_∞[AgUTe₃^1–] layers for CsAgUTe₃. These layers comprise [MTe₄] tetrahedra and [LnTe₆] or [UTe₆] octahedra. Ba or Cs atoms separate these layers. As there are no short Q ··· Q (Q = S or Te) interactions these compounds achieve charge balance as Ba²⁺M⁺Ln³⁺(Q^2–)₃ (Q = S and Te) and Cs⁺Ag⁺U⁴⁺(Te^2–)₃.     

The 3[ndσ*(n+1)pσ] Emissions of Linear Silver(I) and Gold(I) Chains with Bridging Phosphine Ligands

The complexes [Au₃(dcmp)₂][X]₃ {dcmp=bis(dicyclohexylphosphinomethyl)cyclohexylphosphine; X=Cl^? ( 1 ), ClO₄^? ( 2 ), OTf^? ( 3 ), PF₆^? ( 4 ), SCN^?( 5 )}, [Ag₃(dcmp)₂][ClO₄]₃ ( 6 ), and [Ag₃(dcmp)₂Cl₂][ClO₄] ( 7 ) were prepared and their structures were determined by X‐ray crystallography. Complexes 2 – 4 display a high‐energy emission band with λ_max at 442–452 nm, whereas 1 and 5 display a low‐energy emission with λ_max at 558–634 nm in both solid state and in dichloromethane at 298 K. The former is assigned to the ³[5dσ*6pσ] excited state of [Au₃(dcmp)₂]³⁺, whereas the latter is attributed to an exciplex formed between the ³[5dσ*6pσ] excited state of [Au₃(dcmp)₂]³⁺ and the counterions. In solid state, complex [Ag₃(dcmp)₂][ClO₄]₃ ( 6 ) displays an intense emission band at 375 nm with a Stokes shift of ≈7200 cm^?1 from the ¹[4dσ*→5pσ] absorption band at 295 nm. The 375 nm emission band is assigned to the emission directly from the ³[4dσ^*5pσ] excited state of 6 . Density functional theory (DFT) calculations revealed that the absorption and emission energies are inversely proportional to the number of metal ions (n) in polynuclear Au^I and Ag^I linear chain complexes without close metal???anion contacts. The emission energies are extrapolated to be 715 and 446 nm for the infinite linear Au^I and Ag^I chains, respectively, at metal???metal distances of about 2.93–3.02 Å. A QM/MM calculation on the model [Au₃(dcmp)₂Cl₂]⁺ system, with Au???Cl contacts of 2.90–3.10 Å, gave optimized Au???Au distances of 2.99–3.11 Å in its lowest triplet excited state and the emission energies were calculated to be at approximately 600–690 nm, which are assigned to a three‐coordinate Au^I site with its spectroscopic properties affected by Au^I???Au^I interactions.     

(σ3,λ5)‐phosphoranes versus (σ3,λ3)‐thiaphosphiranes: Quantum chemical investigation of products of phosphaalkene sulfurization

By sulfurization of phosphaalkenes ( a ) either (σ³,λ⁵)‐phosphoranes ( b ) or (σ³,λ³)‐thiaphosphiranes ( c ) are formed. In this study, Density Functional Theory (DFT) and coupled cluster (CCSD(T)) calculations have been carried out for model and experimental structures of (σ³,λ⁵)‐phosphoranes and (σ³,λ³)‐thiaphosphiranes to elucidate the factors influencing relative stabilities of b and c . According to the results of quantum chemical calculations, sterically bulky substituents make the phosphorane form more favored. Conversely, electronic effects of the most substituents provide higher stability for thiaphosphirane isomers. The only exception has been found in the cases where the substituent at the phosphorus atom possesses π‐donor and σ‐acceptor properties (e.g., in the case of amino group) and the substituents at carbon atom exhibit σ‐donor/π‐acceptor effects (e.g., silyl groups). The stability of the cyclic form c decreases further, if the substituents at the carbon atom are amino groups. In this case, a quite unusual structure has been theoretically predicted, which is considerably different from those of the hitherto known phosphoranes. It indicates a pyramidal configuration at the phosphorus atom and can be conventionally presented as a donor–acceptor adduct of diaminocarbene with thioxophosphine. © 2012 Wiley Periodicals, Inc.     

Neue Untersuchungen zum Reaktionsverhalten von Triorganylcyclotriphosphanen. Die Kristallstrukturen von [(PPh3)2Pt(PtBu)3], [(PPh3)2Pd(PtBu)2], [(CO)4Cr{(PiPr)3}2], [RhCl(PPh3)(PtBu)3], [(NiCO)6(μ2-CO)3{(PtBu)2}2] und [(CpFeCO)2(μ-CO)(μ-PHtBu)]+ · [FeCl3(thf)]–

New Research of Reaction Behaviour of Triorganylcyclotriphosphines. The Crystal Structures of [(PPh₃)₂Pt(P^tBu)₃], [(PPh₃)₂Pd(P^tBu)₂], [(CO)₄Cr{(PⁱPr)₃}₂], [RhCl(PPh₃)(P^tBu)₃], [(NiCO)₆(μ₂-CO)₃{(P^tBu)₂}₂], and [(CpFeCO)₂(μ-CO)(μ-PH^tBu)]⁺ · [FeCl₃(thf)]^– By the reaction of triorganylcyclotriphosphines with transition metal complexes single- and polynuclear compounds are formed, in which the cyclophosphines are bonded in different ways to the metal, the ring either preserving structure or under going ring opening. Depending on the reaction conditions the following compounds can be characterized: [(PPh₃)₂Pt(P^tBu)₃] ( 1 ), [(PPh₃)₂Pd(P^tBu)₂] ( 2 ), [(CO)₄Cr{(PⁱPr)₃}₂] ( 3 ), [RhCl(PPh₃)(P^tBu)₃] ( 4 ), [(NiCO)₆(μ₂-CO)₃{(P^tBu)₂}₂] ( 5 ) and [(CpFeCO)₂(μ-CO)(μ-PH^tBu)]⁺ · [FeCl₃(thf)]^– ( 6 ). The structures of 1 – 6 were obtained by X-ray single crystal structure analysis ( 1 : space group P2₁/n (No. 14), Z = 4, a = 1279.6(3) pm, b = 1733.1(4) pm, c = 2079.1(4) pm, β = 90.20(3)°; 2 : space group P2₁/c (No. 14), Z = 4, a = 1053.3(2) pm, b = 2085.2(4) pm, c = 1855.7(4) pm, β = 98.77(3)°; 3 : space group P 1 (No. 2), Z = 2, a = 1022.6(2) pm, b = 1026.4(2) pm, c = 1706.0(3) pm, α = 82.36(3)°, β = 86.10(3)°, γ = 64.40(3)°; 4 : space group P 1 (No. 2), Z = 2, a = 980.2(2) pm, b = 1309.5(3) pm, c = 1573.4(3) pm, α = 99.09(3)°, β = 99.46(3)°, γ= 111.87(3)°; 5 : space group P2₁/c (No. 14), Z = 4, a = 1804.0(5) pm, b = 2261.2(6) pm, c = 1830.1(7) pm, β = 96.99(3)°; 6 : space group P2₁/c (No. 14), Z = 4, a = 943.2(3) pm, b = 2510.6(7) pm, c = 1325.1(6) pm, β = 98.21(3)°).     

Kinetics of gas‐phase reactions of CH3OCH2CF3, CH3OCH3, CH3OCH2CH3, CH3CH2OCH2CH3, and CHF2CF2OCH2CF3 with NO3 radicals at 298 K

Rate constants for the gas‐phase reactions of CH₃OCH₂CF₃ (k₁), CH₃OCH₃ (k₂), CH₃OCH₂CH₃ (k₃), and CH₃CH₂OCH₂CH₃ (k₄) with NO₃ radicals were determined by means of a relative rate method at 298 K. NO₃ radicals were prepared by thermal decomposition of N₂O₅ in a 700–750 Torr N₂O₅/NO₂/NO₃/air gas mixture in a 1‐m³ temperature‐controlled chamber. The measured rate constants at 298 K were k₁ = (5.3 ± 0.9) × 10^?18, k₂ = (1.07 ± 0.10) × 10^?16, k₃ = (7.81 ± 0.36) × 10^?16, and k₄ = (2.80 ± 0.10) × 10^?15 cm³ molecule^?1 s^?1. Potential energy surfaces for the NO₃ radical reactions were computationally explored, and the rate constants of k₁–k₅ were calculated according to the transition state theory. The calculated values of rate constants k₁–k₄ were in reasonable agreement with the experimentally determined values. The calculated value of k₅ was compared with the estimate (k₅ < 5.3 × 10^?21 cm³ molecule^?1 s^?1) derived from the correlation between the rate constants for reactions with NO₃ radicals (k₁–k₄) and the corresponding rate constants for reactions with OH radicals. We estimated the tropospheric lifetimes of CH₃OCH₂CF₃ and CHF₂CF₂OCH₂CF₃ to be 240 and >2.4 × 10⁵ years, respectively, with respect to reaction with NO₃ radicals. The tropospheric lifetimes of these compounds are much shorter with respect to the OH reaction. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 490–497, 2009     

Die NMR-Spektren von CF3I,CF3IF2 und CF3IF4

The NMR Spectra of CF₃I, CF₃IF₂, and CF₃IF₄ The ¹⁹F-NMR and ¹³C-NMR spectra of CF₃I, CF₃IF₂ and CF₃IF₄ were recorded in acetonitrile solution. The chemical shifts of the CF₃-groups are strongly dependent on the oxidation state of the iodine atom. With increasing oxidation state the resonances of the CF₃-groups in the ¹⁹F-NMR spectra are characteristically shifted to high field, whereas in the ¹³C-NMR spectra a characteristic shift to low field is measured. The absolute value of the coupling constants ¹J(¹⁹F? ¹³C) increases with increasing oxidation state from 344 Hz (CF₃I) via 354 Hz (CF₃IF₂) to 359 Hz (CF₃IF₄).     

Tunable luminescence and energy transfer process between Tb3+ and Eu3+ in GYAG:Bi3+, Tb3+, Eu3+ phosphors

A series of Eu³⁺ ions co-doped (Gd_0.9Y_0.1)₃Al₅O₁₂:Bi³⁺, Tb³⁺ (GYAG) phosphors have been synthesized by means of solvothermal reaction method. The XRD pattern of GYAG phosphor sintered at 1500 °C confirms their garnet phase. The luminescence properties of these phosphors have been explored by analyzing their excitation and emission spectra along with their decay curves. The excitation spectra of the GYAG:Bi³⁺, Tb³⁺, Eu³⁺ phosphors consists of broad bands in the shorter wavelength region due to 4f⁸ → 4f⁷5d¹ transition of Tb³⁺ ions overlapped with 6s² → 6s¹6p¹ (¹S₀ → ³P₁) transition of Bi³⁺ ions and the charge transfer band of Eu³⁺–O^2?. The present phosphors exhibit green and red colors due to ⁵D₄ → ⁷F₅ transition of Tb³⁺ ions and ⁵D₀ → ⁷F₁ transition of Eu³⁺ ions, respectively. The emission was shifted from green to red color by co-doping with Eu³⁺ ions, which indicate that the energy transfer probability from Tb³⁺ to Eu³⁺ ions are dependent strongly on the concentration of Eu³⁺ ions.