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

Abstract

The crystal structures of two compounds, CuL(2) 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 P2(1)/c and with one molecule in the asymmetric unit. In CuL(2) the four N atoms of two bidentate L ligands coordinate the Cu(II) ion in a distorted tetrahedral geometry with Cu-N distances of 1.98 (5)-2.05 (5) A, while two O atoms from two sulfoxide groups complete the distorted octahedral Cu coordination [Cu-O 2.64 (4), 2.74 (4) A]. In LiNCS.HL, lithium is coordinated by all five ether O atoms with Li-O distances of 2.03 (3)-2.50 (3) A and an N atom from the thiocyanate moiety [Li-N 1.98 (3) A] in a distorted pentagonal pyramidal geometry. Preliminary potentiometric selectivity measurements for ion-selective electrodes (ISEs) based on CuL(2) and ZnL(2) 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 CuL(2), LiNCS.HL, ZnL(2) and HL as input geometries for the minimum energy optimization in vacuo. The results indicate that in ML(2) 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 CuL(2) and ZnL(2) results in different potentiometric selectivities of ISEs based on these compounds.

High-Throughput Small-Molecule Crystallography at the ‘Belok’ Beamline of the Kurchatov Synchrotron Radiation Source: Transition Metal Complexes with Azomethine Ligands as a Case Study

“…The full list of geometrical parameters for 1-Fe is available as Supplementary Materials. The molecular structure of 1-Fe is relatively simple and similar to a series of other related compounds characterized earlier [64][65][66][67][68][69][70][71].…”

Coordination motifs in modern supramolecular chemistry

“…46a) with Cu II ion, while its interaction with the Li + ion leads to an open structure 46b (Fig. 46b) [48].…”

“…This development allows their simultaneous acceptance through distinct donor centers (competitive coordination [44]), for instance in the complex 44 ( Fig. 44) [47,48]. The structurally related azomethine ligand 45 (Fig.…”

Coordination Aspects in Modern Inorganic Chemistry

“…Creation of hybrid biologically perspective ligating systems, for example 181 [113][114][115][116][117], is also interesting. A cycle of transformations 181-184 was carried out, including such ligand 181 and its mononuclear azomethinic 182 and crownether 183 complexes, as well as binuclear structure 184 (confirmed by X-Ray diffraction).…”