نتایج جستجو برای: 4 carboxybenzo 24 crown 8
تعداد نتایج: 1940608 فیلتر نتایج به سال:
In the title compound, [Au(2)Ba(NCS)(4)(C(20)H(24)O(6))](n), the dithio--cyanato-aurate(I) anion adopts a dimeric structure with an Au⋯Au distance of 3.1109 (10) Å; both Au(I) atoms are also bonded to two S atoms. The Ba(II) ion adopts an irregular BaN(3)O(6) geometry, arising from the crown ether and three adjacent thio-cyanate N atoms; the extended structure of the complex can be described as...
Recent experimental results on the proton and neutron polarizabilities are examined from the point of view of backward dispersion relations. Results are found to be in reasonable agreement with the measured values. A rigorous relationship between the nucleon and pion polarizabilities is derived and shown to be in excellent agreement with several models. Research supported in part by the Nationa...
the complexation reactions between tl+ and pb2+ ions and crown ethers 12-crown-4(12c4), 15-crown-5 (15c5), benzo-15-crown-5 (b15c5), 18-crown-6 (18c6), dicyclohexyl-18-crown-6 (dc18c6) and aza-18-crown-6 (a18c6) were studied in 90% acetonitrile and 90% ethanol solutions at 25 °c, using an a.c. polarographic technique. the stoichiometry and stability of the complexes were determined by monitorin...
The synthesis of some thio-oxocrown ether ligands, B1 (1,4-dithio-12-crown-4), B2 (1,7-dithio-12-crown-4), B3 (1,7-dithio-15-Crown-5), B4 (1,7-dithio-18-crown-6), B5 (1,10-dithio-18-crown-6), B6 (1,10-dithio-21-crown-7), under mild conditions, were reported. The ligands were characterized by FT-IR, H NMR and GC-MS spectroscopy. The formation of 1:1 ligand complexes with a variety of metal salts...
We characterize finite, connected posets $P$ having a crown as retract. define multigraph $\mathfrak{F}(P)$ whose vertices are the so-called improper 4-crowns contained in extremal points of $P$, and we show that contains 4-crown retract iff there exists graph homomorphism certain type from to $\mathfrak{C}$ not depending on $P$. Additionally retract-crown with $n \geq 6$ poset induced by $n$ p...
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