Optical properties of composites formed by transition metal macrocyclic complexes intercalated in thiophosphate layered phases

Hybrid materials, formed by strong absorbing macrocyclic complexes [Zn2L]·(NO3)2·H2O or [MnL(H2O)2]·NO3·H2O (LH2: macrocyclic ligand obtained from the [2 + 2] condensation of 2-hydroxy-5-methyl-1,3-benzenedicarbaldehyde and 1,2-diaminobenzene) intercalated in MnPS3 and CdPS3 layered phases, were obtained by the ion exchange method using the potassium precursor, K0.4M0.8PS3(H2O)x. As a result of the conventional synthetic method, using stirring at room temperature, the following composites were obtained: [Zn2L]0.05K0.30Mn0.80PS3(H2O)x (1), [Zn2L]0.10K0.20Mn0.80PS3(H2O)x (2), [Zn2L]0.05K0.30Cd0.80PS3(H2O)x (4), [MnL]0.25K0.15Mn0.80PS3(H2O)x (6), [MnL]0.35K0.05Mn0.80PS3(H2O)x (7) and [MnL]0.25K0.15Cd0.80PS3(H2O)x (9). While the microwave assisted method gives: [Zn2L]0.05K0.30Mn0.80PS3(H2O)x (3), [Zn2L]0.05K0.30Cd0.80PS3(H2O)x (5), [MnL]0.25K0.15Mn0.80PS3(H2O)x (8) and [MnL]0.15K0.25Cd0.80PS3(H2O)x (10). The luminescent properties of the macrocyclic zinc(II) and manganese(III) complexes are not observed in the final composites due to the radiationless decay processes, which are favored by the packing of the macrocyclic species between the layers of the MPS3 phase. The solid reflectance UV–Vis spectra indicate that the absorption edge of the composites is shifted to lower energies, as compared to the potassium precursor, 2.85 eV for K0.4Mn0.8PS3(H2O)x and 3.20 eV for K0.4Cd0.8PS3(H2O)x. The absorption edge varies from 1.85 to 1.70 eV, depending on the stoichiometry of the composite.

Intensively red-brown colored composites are obtained from the light green MnPS3 and light yellow CdPS3 layered phases, once the ZnII and MnIII macrocyclic complexes are intercalated in the corresponding potassium precursor, K0.4M0.8PS3(H2O)x.Figure optionsDownload as PowerPoint slideHighlights
► MnPS3 and CdPS3 intercalated with macrocyclic complexes form red-brown composites.
► The absorption edge of the composites depends on the amount of the macrocyclic guest.
► The composites were non emissive even though the original complexes are luminescent.