Crystallographic and Computational Electron Density of dx2-y2 Orbitals of Azo-Schiff Base Metal Complexes Using Conventional Programs

Abstract

The crystal structures of two azobenzene derivative Schiff base metal complexes (new C44H40CuN6O2 of P-1 and known C44H38MnN6O7 of P21/c abbreviated as Cu and Mn, respectively) were (re-)determined experimentally using conventional X-ray analysis to obtain electron density using a PLATON program. Cu affords a four-coordinated square planar geometry, while Mn affords a hexa-coordinated distorted octahedral geometry whose apical sites are occupied by an acetate ion and water ligands, which are associated with hydrogen bonds. The π-π or CH-π and hydrogen bonding intermolecular interactions were found in both crystals, which were also analyzed using a Hirshfeld surface analysis program. To compare these results with experimental results, a density functional theory (DFT) calculation was also carried out based on the crystal structures to obtain calculated electron density using a conventional Gaussian program. These results revealed that the axial Mn-O coordination bonds of Mn were relatively weaker than the in-plane M-N or M-O coordination bonds.

High anticancer activity in short response time exhibited by a new azobenzene derivative and its copper complex

“…The bond lengths of the imine (ÀN(1)=C(7)À), 1.274(5) Å; azo{ÀN(2)=N(3)À}, 1.258 (4) Å and phenolic-OH {ÀC(1)-O(1)À}, 1.346(5) Å are comparable to literature data. [32][33][34] The shape of the molecule is almost planar, which can be perceived by the torsion angles of (N2-N3-C15-C20), 177.9(3) ; (N3-N2-C11-C10), 178.4(3) ; (C7-N1-C8-C13), À175.2 (3) ; and (C5-C6-C7-N1) 178.9(4) . The ÀN=NÀ bond acquires trans geometry with the torsion angle (C15-N3-N2-C11) of 179.3 (3) .…”

Azophenyl appended Schiff base probe for colorimetric detection of Cu2+ in semi‐aqueous medium and live cell imaging

“…The torsion angles C7-N2-N3-C1 (179.7(2) ), C10-N1-C13-C14 (À179.9(2) ), N2-N3-C1-C6 (À169.9(2) ), C13-N1-C10-C11 (172.0(2) ) and C15-C14-C13-N1 (À178.5(2) ) are in good agreement with planar structure of the molecule. [32][33][34][35][36] The ligand, HAZ, acts as a N,O chelating agent by coordinating to the central Cu (II) ion through the imine-N (C=N) and phenolato-O (-OH) of the orthovanillin moiety generating near square-planar geometry with CuN 2 O 2 coordination sphere (Table S3). The C10-N1-C13-C14 torsion angle in the copper complex is À172.5 (8) , and is comparable to the torsion angle of ligand which is À179.9(2) .…”

“…The azo (-N(2) = N(3)-) and azomethine (-C(13) = N(1)-) linkages in probe HAZ are 1.262(3) Å and 1.294(4) Å, respectively (Table S2), which are comparable to the reported structures. [32][33][34][35][36] All the three aromatic rings in ligand HAZ are almost planar, and the azo part of the ligand appears in trans form. The torsion angles C7-N2-N3-C1 (179.7(2) ), C10-N1-C13-C14 (À179.9(2) ), N2-N3-C1-C6 (À169.9(2) ), C13-N1-C10-C11 (172.0(2) ) and C15-C14-C13-N1 (À178.5(2) ) are in good agreement with planar structure of the molecule.…”

Beyond the Scope of Each Computational Chemistry

“…In recent years, calculations for crystal structure analysis of small molecule compounds have generally been performed relatively smoothly by well-developed programs, from various data processing programs to theoretical calculations for discussion using results. In fact, in our laboratory, we examined whether it is possible to discuss the coordination bond of metal complexes by comparing the electron density by experiment with the electron density by TD-DFT theoretical calculation using a conventional program [1].…”