Solid-state Fluorescence Spectra Research Articles

Absorption, luminescence and crystal structure studies of dysprosium compound with l-α-Alanine: [Dy( l-α-AlaH)(H 2O) 6]Cl 3

The dysprosium compound with l-α-Alamine of the formula [Dy( l-α-AlaH)-(H 2O) 6]Cl 3 was obtained from a water solution in the form of single monoclinic crystals with space group P2 1. Distribution of atoms in the structure of [Dy( l-α-AlaH)(H 2O) 6]Cl 3 is rather close to that of the pseudo P2 1 c group. The other parameters were as follows: a = 8.459(3) A ̊ , b = 15.719(4) A ̊ , c= 11.518(3) A ̊ , β= 102.11(3)°, V = 1497.4 A ̊ 3 , Z = 4, d m = 2.08 g cm −3, d c = 2.07 g cm −3, μ(MoKα) = 5.22 mm −1, λ = 0.71069 Å, F(000) = 900 and T = 299 K. The structure consists of a polymeric chain with oxygen bridges fastening the linear polymer running along the c-axis. The final R factor was 0.026 for 2586 reflections. Each dysprosium ion is coordinated by two carboxylate oxygens and six oxygens from water molecules. The absorption spectrum in the region 5500–40000 cm −1 was recorded along the a-axis and the probabilities of f-f transitions were analysed on the basis of the Judd-Ofelt theory. Solid state fluorescence spectra were recorded at 77 and 300 K and compared with all known dysprosium carboxylates data.

Characterization of oxidized LDPE by solid state fluorescence spectra

AbstractThe fluoresence excitation and emission spectra of commercial LDPE and oxidized LDPEs using phase transferred permanganate as oxidant have been examined using solid state fluorescence spectra. The luminescent impurity species present in commercial polyethylene is found to be olefinic dione. LDPE has an emmission spectra at 330–345 nm and excitation spectra at 235 and 300–310 nm. The emission spectra of oxidized LDPEs contain two main peaks, one at 290–300 nm and the other at 330–345 nm. A comparison of the emission spectra of LDPE blends with the reference compounds, viz., stearic acid and stearone, with those of the oxidized LDPEs proves the presence of “saturated” keto groups (carbonyl in the main chain not conjugated with C = C) in oxidized LDPEs. This also enables us to find out quantitatively the amount of the keto groups present. The estimates thus obtained tally with the results of FT‐IR measurements and follow the increasing order of the stability constant of the permanganate ionpair in benzene.

Spectroscopy and crystal structure of holmium and dysprosium complex compounds with glycine: Ln(Gly) 3(H 2O) 3(ClO 4) 3

Lanthanide(III) complexes with the formula Ln(C 2H 5NO 2) 3(H 2O) 3(ClO 4) 3 (where Ln ≡ Ho, Dy) were obtained in the form of monocrystals which were isomorphic and crystallized in monoclinic space group Cc with the following cell constants: Ho(C 2H 5NO 2) 3(H 2O) 3(C1O 4) 3: a = 20.506(3) b = 9.245(1) c = 23.989(4) A ̊ β = 100.28(1)° V = 4474.7(2) A ̊ 3 Z = 8 d c = 2.20 g cm −3 d m = 2.19(2) M R = 742.53 F(0.00) = 2912 Dy(C 2H 5NO 2) 3(H 2O) 3(ClO 4) 3: a = 20.56(7) b = 9.42(8) c = 24.16(5) A ̊ β = 98.7(5)° Z = 8 d m = 2.19 Results from the X-ray crystal structure determination are given for the Ho 3+ complex compound. The coordination polyhedron of a Ho(III) ion comprises seven oxygen atoms from glycine and two from water molecules. Two oxygen bridges fasten the linear polymer running along the b axis. Absorption spectra recorded in the region 5500–40000 cm −1 were measured along the a axis for the Dy 3+ complex and the probabilities of f-f transitions were analysed on the basis of the Judd-Ofelt theory. Solid state fluorescence spectra of the Dy 3+ ion were recorded at 77 and 300 K. The results are discussed and the Stark levels have been determined. Spectroscopic properties of all the known Dy 3+ carboxylates were compared.

Crystal structure and spectroscopy of lanthanide complexes with glutaric acid [Ln(C 5H 6O 4)(H 2O) 3] · ClO 4

The lanthanide(III) glutarate complexes of formula [Ln(C 5H 6O 4)(H 2O) 3] · ClO 4 (where Ln ≡ Nd, Eu, Ho) were obtained in the form of monocrystals and characterized by single-crystal X-ray diffraction. All the crystals are triclinic, space group P 1 ̄ with the cell constants given below. [p ]Nd(C 5H 6O 4)(H 2O) 3]·ClO 4: a = 7.887(3) A ̊ , b = 8.218(3) A ̊ , c = 10.372(3) A ̊ , α = 109.84(4), β = 84.22(4), γ = 105.44(4) ; [Eu(C 5H 6O 4) (H 2O) 3] · ClO 4: a = 7.839(2) A ̊ , b = 8.135(3) A ̊ , c = 10.328(3) A ̊ , α = 109.63(4), β = 84.42(4), γ = 105.09(4) ; [Ho(C 5H 6O 4)(H 2O) 3]·ClO 4: α = 7.797(3) A ̊ , b = 8.056(3) A ̊ , c = 10.286(3) A ̊ , α = 109.30(4), β = 84.69(4), γ = 104.25(4) . The coordination polyhedra of the lanthanide(III) ions comprise six oxygen atoms from glutarate ions and three from water molecules. Absorption spectra recorded in the region of 11000–40000 cm −1 were measured along the a axis and the probabilities of the f-f transitions were analysed on the basis of the Judd theory. Solid state fluorescence spectra of Nd 3+ and Eu 3+ were recorded at 77 and 300 K; the results are discussed and energy diagrams for the 4I 9 2 and 4I 11 2 levels are proposed.

Coordination chemistry of lanthanides with cryptands. An X-ray and spectroscopic study of the complex Nd 2(NO 3) 6 [C 18H 36O 6N 2]·H 2O

By reacting neodymium nitrate hexahydrate with the cryptand 〈222〉 in methanol, the complex Nd 2-(NO 3) 6[C 18H 36O 6N 2]·H 2O was obtained and analyzed by single-crystal X-ray diffraction. The cell is triclinic P 1 with a = 14.870(2) Å, b = 13.261(2) Å, c = 8.832(1) Å, α = 91.2(1)°, β = 93.4(1)°, γ = 87.6(1)°, Z = 2 and U = 1736.6 Å 3. The structure was refined by least-squares methods to the conventional R = 0.039 for 6177 observed reflections. The compound contains the cations [Nd〈222〉(NO 3)] 2+ and the anions [Nd(NO 3) 5·H 2O] 2−, and is isostructural with the samarium analogue. Solid state fluorescence spectra of the title complex were measured at room and liquid nitrogen temperature, and the transitions 4F 3/2 → 4I 9/2 and 4F 3/2 → 4I 11/2 analyzed.