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Commentaire : square planar geometry with dihedral angles close to zero in the Au1, Au2, and Au4 complexes and a slight flatness deviation to the order of 10 degrees in the Au3a and Au3b complexes, which is due to the steric effects of the sub- stitution at the 8-quinoline group. The results are in good agreement with the experimental ones. On the other hand, in the Fe(III) series complexes, we notice, according to Table S2-b, that the two bonds Fe-Cl1 and Fe–Cl2 have the same exact lengths: 2.189, 2.145, and 2.196 Å, respectively, in the Fe1, Fe2, and Fe4 complexes. Unlike the Fe3a complex, whose Fe–Cl 1 bond increased slightly (2.204 Å) with the Fe–Cl2 bond having recorded a length of 2.193 Å, for the Fe3b complex, the Fe–Cl1 bond was recorded at 2.197 Å, and the Fe–Cl 2 bond was of the order of 2.210 Å. The variation of the M–Cl length could be justified by the steric effects. Another peculiarity that has been noticed in the Fe3a and Fe3b complexes is the position of the substitution of the sulfonyl groups; the mesyl (methylsulfonyl) group in the 8-quinoline position in the Fe3a complex is located in the upper part of the complex as well as the tosyl group in the Fe3b complex, which is located below the coordination plane of the com- plex. Unlike their Au(III)-based analogs, the set of valence and torsion angles around the Fe(III) metallic center indi- cate that all of the complexes have a tetrahedral geometry where the valence angles are close to 109.5 degrees (­ sp3 hybridization). The torsion angles are zero for the angles involving the quinoline bonds with the exception of the Fe3a and Fe3b complexes, which show a slight deforma- tion that can be considered negligible. This indicates that the two bonds (Fe-N 1) and (Fe–X) with 8-quinoline are in the same plane, on the other hand, the two chlorines are outside of the plane with the quinoline group, which corresponds to tetrahedral geometry. The shortest M–Cl, MO, MN, and MS lengths are observed for the Fe(III) complexes. These results are due to the difference in the atomic and Van der Waals radii of Au (1.79; 2.13) and Fe

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