Normal coordinate analysis and DFT calculations of the vibrational spectra for lanthanide(III) complexes with 3-bromo-4-methoxy-2,6-lutidine N-oxide: LnCl3(3Br4CH3OC7H7NO)3 (Ln=Pr, Nd, Sm, Eu, Gd, Dy)

Applications of Density Functional Theory (DFT) to Investigate the Structural, Spectroscopic and Magnetic Properties of Lanthanide(III) Complexes

“…The coordination mode of the ligand could also be inferred by comparing the experimental spectra with those calculated for different model species. B3LYP calculations on the Ln III complexes of 3-bromo-4methoxy-2,6-lutidine N-oxide were shown to reproduce reasonably well the experimental solid state structures and IR and Raman spectra, although an scaling factor of 0.91 had to be used to fit the calculated and experimental wavenumbers [213]. A similar investigation performed on lanthanide(III) complexes of 5aminoorotic acid allowed to establish a bidentate coordination of the carboxylate group of the ligand by comparing the experimental and calculated IR and Raman spectra [214].…”

Noncovalent Interactions at Lanthanide Complexes

“…[56] For example, both Ln Ln 3 + , effective ionic radius, [Å] [25] covalent radius, [Å] [26] van der Waals radius, [Å] [27] La resonance-assisted hydrogen bonding (RAHB) and intramolecular hydrogen bond are important supramolecular synthons in a lanthanide complex (1), [57] whereas potassium ions are sandwiched between two phenyl rings via cation-π interactions that serve to stabilize the divalent Sm(II) centre in 2 [58] (Scheme 1a,b, Figure 1). The intermolecular halogen CÀ Br•••Cl and chalcogen NÀ Se•••N bonds with distances of 3.374 and 3.089 Å in the praseodymium (3) [59] and europium (4) [60] complexes are reported to be the tightest one of their type and are shorter than the sum of the van der Waals radii of 3.60 and 3.45 Å, [61] respectively (Scheme 1c,d). Supramolecular aggregation mediated by halogen CÀ Br Due to the flexible coordination geometry and high coordination numbers, it is difficult to control the nuclearism, crystal parameters and secondary coordination sphere of the lanthanide complexes, but appropriate choice and functionalization of organic ligands with a π-system can allow to construct supramolecular assemblies with desired luminescent, catalytic, magnetic, etc.…”

“…[62][63][64][65][66] Scheme 1. Hydrogen, [57] halogen [59] and chalcogen [60] bonds, as well as cation-π interactions, [58] in lanthanide complexes.…”

“…For example, both resonance‐assisted hydrogen bonding (RAHB) and intramolecular hydrogen bond are important supramolecular synthons in a lanthanide complex ( 1 ), [57] whereas potassium ions are sandwiched between two phenyl rings via cation‐π interactions that serve to stabilize the divalent Sm(II) centre in 2 [58] (Scheme 1a,b, Figure 1). The intermolecular halogen C−Br⋅⋅⋅Cl and chalcogen N−Se⋅⋅⋅N bonds with distances of 3.374 and 3.089 Å in the praseodymium ( 3 ) [59] and europium ( 4 ) [60] complexes are reported to be the tightest one of their type and are shorter than the sum of the van der Waals radii of 3.60 and 3.45 Å, [61] respectively (Scheme 1c,d). Supramolecular aggregation mediated by halogen C−Br⋅⋅⋅π and chalcogen N−Se⋅⋅⋅π quasi‐aromatic bonds with distances of 3.572 and 3.538 Å are also found in the molecular packing diagrams of 3 and 4 , respectively (Scheme 1c,d).…”