Heteronuclear trimetallic and 1D polymeric 3d–4f Schiff base complexes with OCN− and SCN− ligands

Abstract

N¢-bis-(3-methoxysalicylidene)ethylene-1,2-diamine). The structures of 2a,b and 3b-e have been determined by single-crystal X-ray diffraction studies. Structural differences between the complexes affect the photophysical properties, which have been studied in acetonitrile solutions.

Synthesis, crystal structure and luminescent properties of lanthanide extended structure with asymmetrical dinuclear units based on 2-(methylthio)benzoic acid

“…Indeed, the low quantum yields are usually attributed to the deactivation process of the 5 D 0 emitting state by the high-energy O-H oscillators. However, this mechanism is not sufficient to explain the dependence with the excitation wavelength, so we proposed the presence of an additional deactivation mechanism involving a ligand-to-metal charge transfer (LMCT) state [19,21,[40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]. Unfortunately, we were unable to obtain suitable solid-state UVvis absorption of 2 and 3 in order to corroborate the presence of this LMCT state by arithmetic spectral differences.…”

Design and Synthesis of Near‐Infrared Emissive Lanthanide Complexes Based on Macrocyclic Ligands

“…[66] Single-crystal X-ray diffraction studies con- Figure 36. Reaction of the heterobimetallic 3d-4f precursor compounds [ZnLn(L 3 )(H 2 O)(NO 3 ) 3 ] with potassium cyanate (KOCN) or ammonium thiocyanate (NH 4 SCN) in acetonitrile heated to reflux, followed by filtration and slow evaporation of solution, produced analytically pure X-ray quality crystals of the new complexes after several weeks (Scheme 11).…”

Adjustment of coordination environment of Ln3+ ions to modulate near-infrared luminescent properties of Ln3+ complexes

“…The Nd-N bond length lies between those of the two sets of the Nd-O bond lengths, showing the feasibility of the partial or complete replacement of NO 3 − anions with SCN − anions. It should be noted that the effect of Py groups at the axial position of 3d Zn 2+ ions on the formation of a trinuclear Zn 2 Nd array in complex 1, is incomparable to that of trinuclear Zn 2 Ln complexes from the Salen-type Schiff-base ligands with the outer MeO groups [18], in which, the coordination preference for the nitrogen atom from the coordinated SCN − anion at the axial position of 3d Zn 2+ ions occurs in the absence of Py groups. It is of special interest to compare the stepwise formation of the complexes 1-4 with our reported [Zn 2 Ln(L) 2 [19], respectively, which indicates the presence of mixed anions in the four solid complexes.…”