Gy. Argay

Application of luminescence and absorption spectroscopy and x-ray methods to studies of Ln+3 ions interaction with aminoacids

Abstract The Nd +3 , Ho +3 and Eu +3 compounds with glycine, alanine and glutamic acid were synthesized and obtained as monocrystals. Absorption spectra in the range 8000–35 500 cm −1 were measured along the crystallographic axes at room temperature on a Cary 14 spectrophotometer Luminescence spectra were recorded at the same temperature in the range 9000–16 600 cm −1 . Intensities of the ff transitions were analyzed on the basis of the Judd theory, taking the dependence of intensity on the crystallographic axis position into account. Considerable differences in hypersensitive transitions in crystals with alanine, glycine and glutamic acid, whose symmetry changed from triclinic to monoclinic, were explained in terms of differences in the MeO distances.

Stereochemical studies-XXXIII.1 Saturated heterocycles-IX2: Synthesis and conformations of stereoisomeric cis- and troans-tetramethylene- and pentamethylenedihydro-1,3-oxazines

Abstract By the reaction of cis- and trans-2-aminomethylcyclohexanol (1, 2), cis- and trans-2-hydroxymethyl-cyclohexylamine (3,4) and the homologous cycloheptane derivatives (5-8) with ethyl p-chlorobenzimidate (11), cis- and trans-5,6-tetramethylene- and pentamethylene-2,3,5,6-tetrahydro-4H-1,3-oxazines (12,13,16,17) and cis- and trans-4,5-tetramethylene- and pentaimethylene-4,5-dihydro-6H-1,3-oxazines (14, 15, 18, 19) were prepared. The amidine intermediate of the ring-closure reaction was isolated, and the mechanism of the acid-catalysed reaction is discussed. It follows from the 1H NMR data that in the preferred conformations of the cis-tetramethylene-tetrahydrooxazines the methylene group of the hetero ring is equatorial and the hetero atom (O or N) axial. In contrast, the conformation equilibria of the cis pentamethylene derivatives, in accordance with earlier X-ray analysis, are shifted towards the conformer containing the methylene group in isoclinal and the hetero atom in equatorial position. The preferred conformations 12a and 14a of the tetramethylene derivatives 12 and 14 were also determined by X-ray crystal analysis.

Spectroscopy and crystal structure of neodymium coordination compound with glycine: Nd2(Gly)6·(ClO4)6·9H2O

Abstract Neodymium complex compound with glycine: Nd2(Gly)6·(ClO46·9H2O was synthesized and obtained in the form of monocrystals. Absorption spectra recorded in the region of 8000–35 000 cm-1 were measured along the crystallographic axes. Intensities of the f-f transitions were analysed on the basis of the Judd theory. The X-ray crystal structure determination of the complex is reported. Crystals are triclinic, space group P I , with a = 11.554(4) A, b = 14.108(1) A, c = 15.660(3) A, α = 97.14(1)°, β = 102.82(2)°, γ = 105.28(1)°, V = 2355.25 A3 Z = 2, M.W. = 1495.4, Dc = 2.129)(3) g cm-3, Dm = 2.103(1) g cm-3. The structure was solved by Pattersons method and successive Fourier syntheses giving the locations of all nonhydrogen atoms. The final R factor was 0.062 and Rw = 0.073 for 12869 reflections with |Fo| > 5σ|(Fo)|. The asymmetric unit consists of a dimeric formula unit. The coordination polyhedron of Nd atoms comprises seven oxygen atoms from glycine and two from water molecules. The neodymium-glycine bonding mode is compared with that of the calcium-glycine complex.

Reaction of copper(II) with 1-carboxamide-3,5-dimethylpyrazole, 1-carboxamidine-3,5-dimethylpyrazole, 4-acetyl-3-amino-5-methylpyrazole and 5-amino-4-carboxamide-1-phenylpyrazole ☆

Abstract Complex formation of copper(II) bromide and acetate with 1-carboxamide-3,5-dimethylpyrazole (HL3) and copper(II) bromide with 5-amino-4-carboxamide-1-phenylpyrazole (L2), 4-acetyl-3-amino-5-methylpyrazole (HL4) and 1-carboxamidine-3,5-dimethylpyrazole (HL5), was studied. The obtained compounds, CuBr2(L2)2, Cu(L3)2, CuBr2(HL4)2, CuBr2(HL5)2 and [CuBr(HL1)(L3)]2 (HL1 denotes the 3,5-dimethylpyrazole), are characterized by elemental analysis, FT-IR spectrometry, molar conductivity, TG-MS and DSC. The X-ray structure of [CuBr(HL1)(L3)]2 and Cu(L3)2 is discussed. For [CuBr(HL1)(L3)]2 a dimeric penta-co-ordinated structure has been found; the co-ordination around the metal in Cu(L3)2 is trans-square planar. To CuBr2(L2)2 and CuBr2(HL4)2 a nearly tetrahedral, while for CuBr2(HL5)2 an octahedral geometry may be assumed. It means that the geometry of the compounds in the first place depends on the ligand substituents. The course of the complex formation reaction is anion-dependent and may be explained on the basis of Pearsons theory, taking into account the steric factors. A low stability intermediate formation was observed in the thermal decomposition of Cu(L3)2.

Synthesis and molecular structure of salicylaldehydeS-methyl-isothiosemicarbazone, C9H11N3OS

AbstractThe crystal structure of salicylaldehyde S-methylisothiosemicarbazone together with the synthesis applied are reported: C9H11N3OS, monoclinic, P21/n,a=5.169(4),b=16.853 (10),c=11.367(5)Å, β=92.48(1)°,V=989.3(18)Å3,Z=4,dx=1.405g cm−3. The structure was solved by the heavy atom method and refined anisotropically to a residualR=0.046. The molecule is practically co-planar. There is only one basic difference between the title compound H2L and its deprotonated and complexed forms reported hitherto: the nearly 180° difference in rotation about the formal double bond C1—N2. The molecules form hydrogen bonded dimers around

Spectroscopy and crystal structure of holmium and dysprosium complex compounds with glycine: Ln(Gly)3(H2O)3(ClO4)3

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Dihydroperfamine, an alkaloid from haplophyllum glabrinum

.ZusammenfassungSalicylaldehyd-S-methylisothiosemicarbazon wurde dargestellt und die Kristallstruktur vermessen: C9H11N3OS, monoklin, P21/n,a=5,169(4),b=16,853(10),c=11,367(5)Å, β=92,48(1)°,V=989,3(18)Å3,Z=4,dx=1,405 g cm−3. Die Struktur wurde mit Hilfe derPatterson-undFourier-Methode bestimmt und anisotropisch bis zu einemR-Wert von 0,046 verfeinert. Das Molekül ist praktisch eben, wobei ein grundlegender Unterschied zwischen der protonierten (H2L) und der deprotonierten Form in den Komplexver-bindungen besteht. Die Formen unterscheiden sich durch eine Drehung um ca. 180° um die C1—N2-Doppelbindung. Die Moleküle H2L sind durch Wasserstoffbindungen um das Symmetriezentrum zu einem Dimeren verknüpft.

Conformational analysis of thiane-1 imides: an x-ray study of thiane-1-tosylimide and diastereoisomeric 2-alkyl- and 4-phenylthiane-1-tosylimides

Abstract Three novel spirosulfuranes with N and O heteroatoms in axial positions and with five- and six-membered spirorings ( 4–6 ), as well as the molecular complex of the dipolar ion 7 with methanol, have been prepared and their molecular structures determined by X-ray diffraction. The molecular structures of the spirosulfuranes 4–6 show slightly distorted geometries, while that of the dipolar ion 7 is considerably distorted about the central sulfur. The axial interatomic distances for SN and SO in 4–6 range from 1.71 to 1.74 A and from 2.13 to 2.225 A, respectively (1.69 and 2.60 A for 7 ). The axial NSO and the equatorial C ar SC ar angles lie in the intervals 174–179° and 104–105°, respectively, for the spirosulfuranes 4–6 (157 and 104° for 7 ). The SC r bond lengths in all of the compounds investigated are similar to those given for typical S(IV)C ar bonds (1.76–1.82 A). A comparison is also presented between the structural parameters of the spirosulfurances 4–6 and those of the cyclic sulfonium salts 1a–3 and of the molecular complex 7 with analogous structures to the spirosulfuranes studied. The conformations for all of the model compounds as well as for the sulfoxide 8 and sulfide 9 related to the spirosulfuranes and sulfonium salts investigated are also discussed.