THE ION DIPOLE INTERACTION MECHANISM OF MACROCYCLIC ETHERS WITH C-13 DIPOLE DIPOLE RELAXATION-TIME MEASUREMENTS .9. THE STABILITIES OF 18-CROWN-6 COMPLEXES WITH NA+ AND K+ IN D2O AND METHANOL-D
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Tarih
1991
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Science Bv
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
The stabilities of various stoichiometries of the 18-crown-6 ether complexes with Na+ and K+ in methanol-d and D2O were estimated by means of an NMR method using C-13 T1 relaxation time measurements. The experimental coordination conditions were established by maintaining an identical ion/ligand concentration. The evidence was evaluated using the expression of dependence of the mole fraction of the bound ligand, P(AE), to the experimental dipole-dipole relaxation time, T1obs: P(AE) = (1/T1obs - 1/T(E))/(1/T(AE) - 1/T(E)). The equilibrium constants K(e) for complex formation were obtained through the expression and regression of 1/K(e)[E0]n+m-1 = (1 - nP')n(1 - mP')m/P' where P' = P(AE)/(1 + P(AE)(m - 1)). The existence of various n:m ratios of complexes in solution has also been verified with the simulation of the T(AE) behaviour of each stoichiometry.
Açıklama
Anahtar Kelimeler
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Kaynak
Thermochimica Acta
WoS Q Değeri
N/A
Scopus Q Değeri
Q1
Cilt
180
