A dinuclear chromium(III) complex with an oxy-naphthamide ligand: synthesis, crystal structure, spectroscopy, and theoretical study

The bis -ethoxy-bridged dinuclear chromium(III) complex, [(H 2 L)Cr(μ-OEt)Cr(H 2 L)] ( 1 ) (H 4 L = N,N′ -(1,2-phenylene)bis(1-hydroxy-2-naphthamide)) was synthesized and characterized. Single-crystal X-ray diffraction shows that the acetone-solvate ( 1 . 4 acetone) crystallized as a neutral, centrosymmetric dinuclear complex with slightly distorted octahedral coordination around the Cr(III) centers and a Cr┄Cr distance of 3.052(1) Å. Two Cr(III) centers are chelated and bridged by two H 2 L 2− quadridentate ligands, while two ethoxo bridging ligands complete the coordination sphere. A Hirshfeld Surface Analysis showed a quite homogeneous and densely packed surface of the molecule and confirmed the intermolecular N–H···O and C–H···π interactions. Lacking of T -dependent magnetization measurements, we embarked on experimental FT-IR, UV–vis absorption, and EPR spectroscopy showing good to excellent agreement with density functional theory (DFT) and TD-DFT calculations. Taken all together, they strongly support the assignment of the ground state of the complex to a total spin S = 3 (spin multiplicity = septet).