Showing papers by "Andrei V. Churakov published in 1997"
TL;DR: The perchlorate of 2-{2-[4-(13-aza-1,4,7,10-tetroxa-13-cyclopentadecyl)phenyl]ethenyl}-3-ethylbenzothiazolium (3) has been synthesised and its structure determined in the crystalline state by X-ray diffraction and in solution in acetonitrile by 1H NMR methods as mentioned in this paper.
Abstract: The perchlorate of 2-{2-[4-(13-aza-1,4,7,10-tetroxa-13-cyclopentadecyl)phenyl]ethenyl}-3-ethylbenzothiazolium (3) has been synthesised and its structure determined in the crystalline state by X-ray diffraction and in solution in acetonitrile by 1H NMR methods. Complexation with barium and silver cations in solution has been studied in comparison with other model azacrown molecules by spectrophotometric and potentiometric methods. With the exception of the puckered azacrown moiety, the structure of 3 is remarkably planar, consistent with extensive π-conjugation throughout the remainder of the molecule in both solid and solution states. Compound 3 forms a stable 1∶1 complex with Ba2+ ions in acetonitrile, with a stability constant of K1 = 80 ± 10 dm3 mol–1; the complexation results in major changes in the electronic absorption spectrum of 3, consistent with binding to the azacrown moiety. A model compound, phenylaza-15-crown-5 (2a), was found to bind Ba2+ to form both a 1∶1 ligand–metal complex (LM), with a stability constant of K1 = (2.0 ± 0.2) × 104 dm3 mol–1, and a 2∶1 (L2M) complex, with a stability constant of K2 = 220 ± 20 dm3 mol–1 for binding of the second ligand. The electronic absorption and NMR spectra both indicate binding of the ‘hard’ Ba2+ cation to the azacrown oxygen atoms. However, by contrast, the evidence from NMR data shows that the ‘soft’ Ag+ cation complexes with 2a mainly through a strong interaction with the azacrown nitrogen atom, giving a 1∶1 complex with a stability constant of K1 = 6 ± 1 dm3 mol–1, determined by potentiometry. No complexation of 3 with Ag+ is observed. Studies of the simple aza-15-crown-5 ether reveal strong complexation with both Ba2+ (K1 × K2 > 1012 dm6 mol–2) and Ag+ [K1 = (1.15 ± 0.10) × 104 dm3 mol–1 and K2 = 450 ± 20 dm3 mol–1].
57 citations
TL;DR: In this article, an improved synthesis of 2,2′-bis(1-indenyl)propane and the corresponding ansa-complexes of zirconium are reported.
27 citations
TL;DR: In this article, the synthesis of trialkylstannyl esters of tris(2-hydroxyalkyl)amines, N(CH2CHROSnAlk3)3 (9-11 (R = H, Me; Alk = Et, Bu), react with X3GeC(R1)(R2)COOR3 (12-17) (X Cl or Br; R1, R2=H, Me, Ph, SiMe3, COOEt; R3=Me, Et)
Abstract: Trialkylstannyl esters of tris(2-hydroxyalkyl)amines, N(CH2CHROSnAlk3)3 (9-11 (R = H, Me; Alk = Et, Bu), react with X3GeC(R1)(R2)COOR3 (12–17) (X Cl or Br; R1, R2=H, Me, Ph, SiMe3, COOEt; R3=Me, Et) to give esters of α-germatranylcarboxylic acids, N(CH2CHRO)3GeC(R1)(R2)-COOR3 (1–8), in high yields. The synthesis of esters 12–17 is reported. Esters of α-germatranyldiphenylacetic acid 24 and 25 can be obtained by treatment of diphenylketene with Et3SnOMe to give in situ Et3SnC(Ph2)COOMe (23), followed by reaction with GeCl4 to give in situ Cl3GeC(Ph2)COOMe (22 and further reactions with 9 or 11, respectively. Reduction of germatrane 6 with LiAlH4 in diethyl ether leads to cleavage of the germanium-carbon bond with subsequent formation of (2-hydroxyethyl)trimethylsilane. The crystal structures of 3, 6 and 7 are reported. 1-Acyloxygermatranes 26 and 27 are obtained by treatment of 1-methoxygermatrane (28) with diphenyl- and dichloroacetic acid, respectively.
21 citations
TL;DR: In this paper, the synthesis of the new compound N(CH2CH2O)3GeY (2 YFluorenyl; 4 YPhCC) by the reaction of X 3GeY with N( CH 2CH2OSnR3)3 (3 REt; 6 RBu) is reported.
Abstract: Syntheses of the title compounds, viz. N(CH2CH2O)3GeY (2 YFluorenyl; 4 YPhCC) by the reaction of X3GeY (1 YFluorenyl, XBr; 5 YPhCC, XCl) with N(CH2CH2OSnR3)3 (3 REt; 6 RBu) are reported including the preparation of the new compound 1. Identity and structures were established by elemental analyses, 1H and 13C NMR spectroscopy. 2 and 4 were characterized by mass spectrometry. Single crystal structures of 1, 2 and 4 were determined by X-ray diffraction methods.
Darstellung, Charakterisierung und Strukturen von 1-(9-Fluorenyl)germatran and 1-(Phenylacetylenyl)germatran
Uber die Synthesen der Titelverbindungen, namlich N(CH2CH2O)3GeY (2 YFluorenyl; 4 YPhCC) durch Reaktion von X3GeY (1 YFluorenyl, XBr; 5 YPhCC, XCl) mit N(CH2CH2OSnR3)3 (3 REt; 6 RBu) wird berichtet und die Darstellung der neuen Verbindung 1 wird beschrieben. Die Strukturen der Verbindungen wurden durch Elementaranalysen sowie mittels 1H and 13C NMR-Spektroskopie bestimmt, 2 und 4 massenspektrometrisch charakterisiert. 1, 2 und 4 wurden mit Rontgenbeugungsmethoden analysiert.
20 citations
TL;DR: A series of amido derivatives of arsenic cyclopentadienyls (Cp′AsNR) n (4-6) have been synthesized by the reaction of CpAsX 2 (1-2 ) with an excess of amine as mentioned in this paper.
15 citations