Even-Odd Effect of 35Cl Quadrupole Coupling Constants in Solid n-Alkylammonium Chlorides (C5 - C10)
نویسنده
چکیده
35Cl NMR spectra were measured using the highest-temperature solid phase of n-CxH(2x+1) NH3Cl and n-CxH(2x+1)ND3Cl (x= 5−10). The observed quadrupole coupling constants (e2Qqh−1) decreased upon heating in this phase, and significant frequency differences of ca. 20 – 30 kHz were detected between the -NH3 and -ND3 analogs. In the low-temperature range of this phase, the observed e2Qqh−1 values for x = 8,10 were larger than those for x = 5,7,9, which is attributable to the even-odd effect. Point-charge calculation was employed to explain this effect, in which the geometrical parameters and electric charge distributions of the cations were estimated using the B3LYP/631G∗ and B3LYP/6-31+G∗∗ method, respectively. The results show that the double-layer width between the Cl− ions at the 2a and 4f sites strongly contributes to the e2Qqh−1 value.
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