. 2021 Apr 12;26(8):2225. doi: 10.3390/molecules26082225

Table 4.

Characteristics of Na⁺, K⁺, and Ca²⁺ complexes with diaza-crown ethers calculated by DFT method.

Ligand	Cation (Mⁿ⁺)	NBO Charge at the Cation	Metal-Oxygen Distances, Å	Metal-Nitrogen Distances, Å	ΔU, kcal/mol
12	Na⁺	0.963	2.192…4.434	3.582	−71.06
	K⁺	0.979	2.576…4.916	4.008	−50.65
	Ca²⁺	1.814	2.302…2.444	2.673	−216.65
13	Na⁺	0.899	2.332…2.622	2.930, 3.030	−75.26
	K⁺	0.919	2.733…2.938	3.189, 3.130	−55.84
	Ca²⁺	1.813	2.295…2.490	3.092, 2.618	−239.26
14	Na⁺	0.886	2.316…2.621	3.146, 3.267	−81.89
	K⁺	0.924	2.733…3.007	3.267, 3.690	−59.46
	Ca²⁺	1.794	2.327…2.444	2.993, 3.055	−257.27
15	Na⁺	0.951	4.145 *, 2.257…2.507	3.581, 3.624	−79.30
	K⁺	0.967	4.499 *, 2.636…2.980	3.933, 3.997	−60.10
	Ca²⁺	1.818	2.674 *, 2.279…2.385	3.090, 2.837	−234.04
19	Na⁺	0.900	2.334…2.373	2.514, 2.516	−81.01
	K⁺	0.944	2.709…2.749	2.882, 2.885	−59.44
	Ca²⁺	1.790	2.316…2.382	2.482, 2.480	−240.81

* Distance from the central ion to the oxygen atom in the (CH₂)₂O(CH₂)₂ segment connecting nitrogen atoms of the macrocycle.