Chiral Recognition of Azo-Schiff Base Ligands, Their Cu(II) Complexes, and Their Docking to Laccase as Mediators

Abstract

Chiral crystals were discovered due to spontaneous resolution when enantiomers of 4-phenyldiazenyl-2-[(R or S)-(1-phenylethyl)-iminomethyl]phenol and its racemic mixture were prepared. Using two ligands per molecule, optically active R,R and S,S enantiomers and meso R,S diastereomer of Cu(II) complexes were prepared. Strong chiral recognition was expected for them. Laccase has attracted attention as a catalyst that reduces oxygen to water in a cathode of biofuel cells, which can be effectively mediated by metal complexes. Furthermore, azobenzene can align perpendicularly to the polarization direction of irradiating linearly polarized ultraviolet light (Weigert effect) as well as to the conventional cis-trans photoisomerization accompanying the shift of redox potential. Thus, we also studied the photo-induced control of cis-trans forms and the alignment of these Cu(II) complexes as a mediator to fit laccase appropriately. We discuss photo-induced control on not only electronically but also sterically-favored redox conditions. The meso(R,S)-form of the Cu(II) complex in cis-form was found to be the best at increasing the current of cyclic voltammetry (CV) among the three R,R and S,S enantiomers and the R,S diastereomer of the Cu(II) complexes.

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

“…Green prismatic single crystals (0.60 × 0.30 × 0.20 mm 3 ) of new Cu were obtained in a similar way to that in the literature [ 16 ] and analyzed, while the present analysis of Mn was a re-determination of CCDC 1457179 [ 17 ] to obtain electron density data ( Supplementary Materials ). The samples were set on top of a glass capillary, coated with a thin layer of Araldite epoxy resin.…”

Synthesis and Characterization of Some Transition Metal Complexes with New Azo- Schiff Base Ligand 3,4-bis(((1E,2E)-2-((2-((4-((Z)-(3-Hydroxyphenyl)Diazenyl)Naphthalen-1-yl)amino)ethyl)imino)-1,2-Diphenylethylidene)Amino)Phenyl)(phenyl)Methanone

“…The complex of Ni(II) exhibits broad band in the 3000-3600 cm -1 range and this may be attributed to the presence of water molecular outside the coordination sphere [21,22]A strong IR absorption band observed in the free ligand 1620 cm -1 assignable to the absorption of the imine groups (<C=N-) in the free azo-Schiff base ligand (8) was shifted and changing in the range of 1531-1630 cm -1 and the visualizes the coordination by the nitrogen atoms of imine groups to the metal ions [23]. Also, spectrum of the new ligand 8 displays the azo group (-N=N-) This band did not show any frequency shifting in infrared spectra of the chelates complexes [24] while in the low frequency regions, bands were detected around 542-596 cm -1 ranges assigned to υ(M-N) [25]. Thus, the above infrared spectral data lead to the suggestion that the coordination sites of the new ligand (8) were by the nitrogen atom of imine group (-C=N)) and the nitrogen atom (NH) of Naphthyl ring.…”

Synthesis and Characterization of Some New Azo-Schiff Bases as Energy Rich Candidate Compounds Derived from 1, 5-Diaminoanthraquinone by Fusion Method

“…Their multi sites of coordination were precious opportunity for those who carry out researches. Relating to coordination chemistry [7][8][9][10][11][12][13][14][15]. For researchers interesting in the field of biological activities, it was a chance to test the double effect of their both groups [16][17][18][19][20].…”

“…3204) cm -1 in addition to the shift in the location of intra hydrogen bonded carbonyl group from (1609 cm -1 ) of the starting material to (1655-1659) cm -1 are strong evidences for the development of the product. The appearance of new sharp bands at (1612-1620) cm -1 referring to (CH=N group) indicates the formation of Schiff bases[7][8][9][10][11][12][13][14][15][16][17][18]. Moderate bands at (1580-1595) cm -1 referring to the stretching absorption of aromatic (C=C) bond and weak bands (1017-1060) cm -1 due to (N=N) group are another evidence for the formation of the desired product.…”