Synchrotron powder diffraction in a systematic study of 4′-[2-(tosylamino)benzylideneamino]-2,3-benzo-15-crown-5 complexes

• Published in: Acta crystallographica. Section B, Structural science Structural science, 2007-06, Vol.63 (3), p.402-410
• Main Authors: Dorokhov, Andrey V., Chernyshov, Dmitrii Yu, Burlov, Anatolii S., Garnovskii, Alexandr D., Ivanova, Irina S., Pyatova, Elena N., Tsivadze, Aslan Yu, Aslanov, Leonid A., Chernyshev, Vladimir V.
• Format: Article
• Language: English
• Subjects: Chemical compounds; crown ether; Crystallography; DFT calculations; Geometry; Ions; structure solution from powder diffraction data; synchrotron powder diffraction data; Theory
• ISSN: 0108-7681; 2052-5192; 1600-5740; 2052-5206
• DOI: 10.1107/S0108768107003898

The crystal structures of two compounds, CuL2 and LiNCS·HL [HL = 4′‐[2‐(tosylamino)benzylideneamino]‐2,3‐benzo‐15‐crown‐5], have been determined from synchrotron powder diffraction data. Both compounds crystallize in the monoclinic space group P21/c and with one molecule in the asymmetric unit. In CuL2 the four N atoms of two bidentate L ligands coordinate the CuII ion in a distorted tetrahedral geometry with Cu—N distances of 1.98 (5)–2.05 (5) Å, while two O atoms from two sulfoxide groups complete the distorted octahedral Cu coordination [Cu—O 2.64 (4), 2.74 (4) Å]. In LiNCS·HL, lithium is coordinated by all five ether O atoms with Li—O distances of 2.03 (3)–2.50 (3) Å and an N atom from the thiocyanate moiety [Li—N 1.98 (3) Å] in a distorted pentagonal pyramidal geometry. Preliminary potentiometric selectivity measurements for ion‐selective electrodes (ISEs) based on CuL2 and ZnL2 demonstrated significant differences in their selectivity. In order to find a possible reason for this, theoretical calculations at the DFT (B3LYP) level were performed. These calculations used the crystal structures of CuL2, LiNCS·HL, ZnL2 and HL as input geometries for the minimum energy optimization in vacuo. The results indicate that in ML2 complexes (M = Cu, Zn) the electronic structure of the metal ion determines the spatial orientation of benzo‐15‐crown‐5 macrocycles, and their different orientation in CuL2 and ZnL2 results in different potentiometric selectivities of ISEs based on these compounds.