Structural organization of mercury(II) and copper(II) dithiocarbamates from EPR and 13C and 15N MAS NMR spectra and X-ray diffraction analysis

2008 ◽  
Vol 34 (1) ◽  
pp. 59-69 ◽  
Author(s):  
A. V. Ivanov ◽  
E. V. Korneeva ◽  
B. V. Bukvetskii ◽  
A. S. Goryan ◽  
O. N. Antzutkin ◽  
...  
1998 ◽  
Vol 13 (8) ◽  
pp. 2184-2189 ◽  
Author(s):  
J. Temuujin ◽  
K. Okada ◽  
K. J. D. MacKenzie

Aluminosilicate precursors were prepared by mechanochemical treatment of gibbsitesilica gel mixtures. The effect of grinding on their structure and thermal behavior has been examined by 27Al and 29Si MAS NMR, x-ray diffraction (XRD), differential thermal analysis-thermogravimetry (DTA-TG), and Fourier transform infrared (FTIR). After 8 h grinding, the hydrated alumina was completely changed to an amorphous phase which showed a new exothermic DTA peak at about 980 °C due to the formation of γ–Al2O3 or spinel phase. This behavior was related to changes in the Al and Si environments, as deduced from the MAS NMR spectra. With increased grinding time, some 4-coordinated Al appears, together with an Al resonance at about 30 ppm. Simultaneously, a new Si resonance appears at about −90 ppm, indicating a greater degree of homogeneity in the ground samples. Mullite crystallizes at 1200 °C from samples ground for 8–20 h, its XRD intensity increasing with increased milling times, in agreement with the NMR, DTA, and FTIR data. Changes in the Al and Si environments during heat treatment, as reflected by the NMR spectra, are also reported.


1983 ◽  
Vol 38 (11) ◽  
pp. 1454-1459 ◽  
Author(s):  
Jörn Müller ◽  
Rainer Stock ◽  
Joachim Pickardt

Abstract Reaction of [(nbd)RhCl]2 (nbd = nor bornadiene) with CH3Li and 6.6-dimethylfulvene yields (nbd)Rh(2-propenylcyclopentadienyl). (cod)Rh(Cl)P(CH3)3 (cod = 1.5-cyclooctadiene), obtained by cleavage of [(cod)RhCl]2 with P(CH3)3, reacts with 6.6-dimethyl-fulvene and CH3Li or i-C3H7MgBr with substitution of cod by dimeric fulvene ligands the nature of which depends on the alkyl reagent. The new complexes were characterized by NMR spectra and in one case by X-ray diffraction analysis.


1983 ◽  
Vol 48 (9) ◽  
pp. 2593-2603 ◽  
Author(s):  
Karel Baše

Decaborane(14) reacts with NaNO2 in tetrahydrofuran forming the [9-tetrahydrofuran-6-NO2B10H12]- salt which after protonization with concentrated H2SO4 or diluted HCl affords azaboranes 6-NB9H12 and 4-NB8H13, respectively. The 6-NB9H12 azaborane is hydrolyzed to the 4-NB8H13 azaborane and reacts with Lewis bases under the formation of the 9-L-6-NB9H12 ligand derivatives (L = (CH)S, CHCN, (CH)P). By the reduction of 9-CHCN-6-NBH with LiAlH4 in tetrahydrofuran the 6-NB9H13- anion was prepared. By an analogous reaction of decaborane(14) with KHSO3 in water and by a subsequent protonization of the formed intermediate with concentrated H2SO4 or diluted HCl the thiaboranes 6-SB9H11 and 4-SB8H12, respectively, were prepared. The reaction of decaborane(14) with Na2SeO3 in tetrahydrofuran followed by the protonization of the intermediate with diluted HCl afforded the 7,8-Se2B9H9 species. Structures of all compounds were proposed on the basis of the 11B and 1H NMR spectra; in the case of 4-NB8H13, the structure was determined by the X-ray diffraction analysis.


1999 ◽  
Vol 54 (7) ◽  
pp. 929-939 ◽  
Author(s):  
Miki Hasegawa ◽  
Yasunori Yamada ◽  
Ken-ichi Kumagai ◽  
Toshihiko Hoshi

The electronic and molecular structure of 2,6-bis{N-(2-hydroxyphenyl)iminomethyl}-4- methylphenol (hpimp) is clarified from the measurements of electronic absorption and 1H NMR spectra in various solvents and an X-ray diffraction analysis, together with MO calculations. Electronic absorption bands of hpimp are at 422, 397.9, 359, 341, 294.3, 265.8, and 224 nm in the non-polar solvent cyclohexane. In polar solvents, such as methanol, an additional band which is assigned to a partly formed keto-amine hpimp, is observed at 499 nm. From the 1H NMR spectra it is seen that hpimp exists in the enol-imine form in non-polar solvents, and as an equilibrium mixture of enol-imine and keto-amine forms in polar solvents. Each electronic absorption band of solid hpimp in a KBr disk is broadened compared with the solution state, and an additional band, again assigned to the keto-amine form, appears around 499 nm. An X-ray diffraction analysis shows that hpimp assumes a keto-amine structure in the solid state, and forms a column structure along the c-axis. MO calculations suggest that the enol-imine hpimp has a twist structure around the two C−C single bonds, the twist angle being 100° to 120°.


1998 ◽  
Vol 21 (1-3) ◽  
pp. 19-25 ◽  
Author(s):  
M Solache ◽  
I Garcı́a ◽  
P Bosch ◽  
S Bulbulian ◽  
A Blumenfeld ◽  
...  

1992 ◽  
Vol 57 (6) ◽  
pp. 1299-1313 ◽  
Author(s):  
Juraj Bernát ◽  
Ladislav Kniežo ◽  
Gabriela Birošová ◽  
Miloš Buděšínský ◽  
Jaroslav Podlaha ◽  
...  

Substituted 4-hydroxy-1,3-dioxanes II react rapidly with PO(NCS)3 to give 4-isothiocyanato-1,3-dioxanes III. The 1H NMR spectra showed that in the isothiocyanate IIIa the predominant stereoisomer has its NCS group in axial position. The addition of benzylamine to the isothiocyanates IIIa and IIIb gave uniform thioureas IVa and IVb with equatorial alkyl groups at 2 and 6 positions and axial thioureido group at 4 position. On the other hand, the isothiocyanate IIIc reacts with benzylamine to give a mixture of three stereoisomeric thioureas V,VI, and VIII. The structure of VI was proved by means of X-ray diffraction analysis; in crystalline form the molecules of VI are present as H-bonded dimers (N-H...O).


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