Conductometric Studies of Thermodynamics of 1,10-Didecyl-1,10-diaza-18-crown-6 Complexes with Li⁺, Na⁺, K⁺, Cs⁺, NH₄⁺, Mg²⁺, and Ca²⁺ Ions in Acetonitrile, Methanol, and Ethanol Solutions

Table 1

Formation constants for different M𝑛+-DD18C6 complexes in acetonitrile, methanol, and ethanol solvents.

Cation^a	Solvent	Log𝐾𝑓
		15°C	𝜒^2	25°C	𝜒^2	35°C	𝜒^2	45°C	𝜒^2
	AN	6.70	0.277	6.49	0.383	6.18	0.117	6.01	0.004
Li^+ (0.74)	MeOH	3.04	0.006	3.69	0.009	3.18	0.009	2.83	0.167
	EtOH	1.86	0.141	1.67	0.003	1.54	0.126	1.27	0.027
	AN	6.87	0.153	6.50	0.104	6.23	0.072	6.00	0.075
Na^+ (1.02)	MeOH	3.85	0.006	3.75	0.005	3.58	0.018	3.54	0.021
	EtOH	2.22	0.049	2.10	0.025	1.71	0.009	1.45	0.003
	AN	7.00	0.012	6.50	0.014	6.00	0.011	5.62	0.012
K^+ (1.38)	MeOH	3.63	0.011	3.07	0.007	2.40	0.010	2.28	0.010
	EtOH	2.26	0.012	2.09	0.006	1.72	0.003	1.60	0.004
	AN	6.48	0.016	6.20	0.135	6.07	0.154	6.00	0.004
NH4^+ (1.48)	MeOH	3.43	0.005	2.91	0.054	2.63	0.068	1.83	0.203
	EtOH	2.17	0.080	2.01	0.062	1.65	0.061	1.32	0.093
	AN	2.95	0.008	2.61	0.033	2.31	0.030	1.62	0.007
Cs^+ (1.70)	MeOH	3.73	0.031	3.34	0.056	3.15	0.024	2.34	0.016
	EtOH	2.32	0.023	2.13	0.010	1.85	0.010	1.71	0.006
	AN	5.97	0.040	6.04	0.031	6.04	0.031	5.70	0.019
Mg^2+ (0.72)	MeOH	4.02	0.021	4.05	0.047	4.09	0.046	4.17	0.026
	EtOH	1.98	0.017	1.87	0.010	1.77	0.003	1.48	0.013
	AN	5.85	0.125	5.80	0.097	5.75	0.093	5.69	0.089
Ca^2+ (1.00)	MeOH	4.27	0.059	—^b	1.02	—^b	0.86	—^b	0.64
	EtOH	3.09	0.125	2.65	0.045	2.16	0.105	1.83	0.220

^aThe values in parenthesis are the ionic sizes in Å [15]
^bInsufficient fit.