Synthesis, crystal structure, luminescent properties, and magnetic properties of lanthanide(III) complexes containing the chiral (S,S/R,R)-N, N'-bis(3,5-dinitrosalicylidene)-1,2-cyclohexanediamine ligand

In this work, we report novel enantiopure mononuclear complexes (teaH)[Ln((S,S)-dnsalcd)2] and (teaH) [Ln((R,R)-dnsalcd)2] (Ln = Eu3+ for 1 and 4, Tb3+ for 2 and 5, and Sm3+ for 3 and 6), where teaH = triethy lammonium and (S,S/R,R)-H2dnsalcd = (S,S/R,R)-N,N'-bis(3,5-dinitrosalicylidene)-1,2-cyclohexanedia mine. Their unique structural features have been studied by single crystal diffraction and chiral and magnetic properties have been investigated by circular dichroism and susceptibility, respectively. Notably, 1 and 3 were found to be isomorphous and exhibited a single intramolecular 7C -7C interaction between two (S,S)-dnsalcd2-ligands. In contrast, 2 and 5 were found to be isomorphous and displayed two intramolecular 7C -7C interactions between two (S,S/R,R)-dnsalcd2-ligands. Interestingly, strong Eu3+/Sm3+-based emissions in the solid and solution states were observed by efficient antenna effects due to the 7C -7C interaction modes of the coordinated ligands. Furthermore, density functional theory calculations indicated that 1 contained a single localized benzene group in the highest occupied molecular orbital (HOMO), whereas 2 exhibited full delocalization via 7C -7C interactions in the HOMO.(c) 2023 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.