The intermolecular interactions in the structures of a series of Schiff base ligands have been thoroughly studied. These ligands can be obtained in different forms, namely, as the free base 2‐[(2
E)‐2‐(1
H‐imidazol‐4‐ylmethylidene)‐1‐methylhydrazinyl]pyridine, C
10H
11N
5, 1 , the hydrates 2‐[(2
E)‐2‐(1
H‐imidazol‐2‐ylmethylidene)‐1‐methylhydrazinyl]‐1
H‐benzimidazole monohydrate, C
12H
12N
6·H
2O, 2 , and 2‐{(2
E)‐1‐methyl‐2‐[(1‐methyl‐1
H‐imidazol‐2‐yl)methylidene]hydrazinyl}‐1
H‐benzimidazole 1.25‐hydrate, C
13H
14N
6·1.25H
2O, 3 , the monocationic hydrate 5‐{(1
E)‐[2‐(1
H‐1,3‐benzodiazol‐2‐yl)‐2‐methylhydrazinylidene]methyl}‐1
H‐imidazol‐3‐ium trifluoromethanesulfonate monohydrate, C
12H
13N
6+·CF
3O
3S
?·H
2O, 5 , and the dicationic 2‐{(2
E)‐1‐methyl‐2‐[(1
H‐imidazol‐3‐ium‐2‐yl)methylidene]hydrazinyl}pyridinium bis(trifluoromethanesulfonate), C
10H
13N
52+·2CF
3O
3S
?, 6 . The connection between the forms and the preferred intermolecular interactions is described and further studied by means of the calculation of the interaction energies between the neutral and charged components of the crystal structures. These studies show that, in general, the most important contribution to the stabilization energy of the crystal is provided by π–π interactions, especially between charged ligands, while the details of the crystal architecture are influenced by directional interactions, especially relatively strong hydrogen bonds. In one of the structures, a very interesting example of the nontypical F…O interaction was found and its length, 2.859 (2) Å, is one of the shortest ever reported.
相似文献