Synthesis, Crystal Structure, and Luminescence Properties of the Iso-Reticular Series of Lanthanide Coordination Polymers Synthesized from Hexa-Lanthanide Molecular Precursors.

Microwave-assisted reactions in DMSO, between a hexa-lanthanide octahedral complex ([Ln(μ-O)(μ-OH)(NO)(HO)·2NO·2HO] with Ln = Nd-Yb plus Y) and either 3-halogenobenzoic acid (hereafter symbolized by 3-bH with = f or c for fluoro or chloro, respectively) or 4-halogenobenzoic acid (hereafter symbolized by 4-bH with = f, c, or b for fluoro, chloro, or bromo, respectively), lead to 1D lanthanide coordination polymers. These coordination polymers are almost iso-reticular. The crystal structure is described on the basis of the coordination polymer with chemical formula [Tb(4-fb)(DMSO)(HO)·DMSO] obtained from 4-fluorobenzoic acid (4-fbH) and the Tb-based octahedral complex: It crystallizes in the triclinic system, space group 1̅ (n°2), with the following cell parameters: = 9.8561(9) Å, = 10.5636(9) Å, = 15.1288(15) Å, α = 100.840(3)°, β = 95.552(3)°, γ = 110.482(3)°, = 1426.4(3) Å, and = 2. It can be described on the basis of 1D molecular chains. Luminescence properties of the Tb and Eu derivatives have been measured and compared vs the halogeno-function and its position ( or ). Some molecular alloys have also been prepared to estimate the strength of the intermetallic energy transfers. To confirm that the hexa-nuclear complexes (and not the halogenated ligand) have a structuring effect for the formation of the straight chain-like molecular motif, another coordination polymer with chemical formula [Tb(4-npa)DMSO·DMSO·HO] where 4-npaH symbolizes 4-nitro-phenyl-acetic acid has been prepared. It crystallizes in the triclinic system, space group 1̅ (n°2) with the following cell parameters: = 7.8784(8) Å, = 14.8719(16) Å, = 15.2753(17) Å, α = 73.612(4)°, β = 86.406(4)°, γ = 83.104(4)°, = 1703.8(3) Å, and = 2. Its crystal structure can be described on the basis of a molecular motif that is similar to the one observed in the five previous crystal structures which confirms the structuring effect of the hexa-nuclear complexes.