Metal-Organic Framework vs. Coordination Polymer—Influence of the Lanthanide on the Nature of the Heteroleptic Anilate/Terephtalate 3D Network

Abstract

Metal-organic frameworks (MOFs), whose definition has been regularly debated, are a sub-class of coordination polymers (CPs) which may feature both an overall 3D architecture and some degree of porosity. In this context, MOFs based on lanthanides (Ln-MOFs) could find many applications due to the combination of sorption properties and magnetic/luminescent behaviors. Here we report rare examples of 3D Ln-CPs based on anilate linkers, obtained under solvothermal conditions using a heteroleptic strategy. The three compounds of formula [Yb2(μ-ClCNAn)2(μ-F4BDC)(H2O)4]·(H2O)3 (1), [Er2(μ-ClCNAn)2(μ-F4BDC)(H2O)4]·(H2O)4 (2) and [Eu2(μ-ClCNAn)2(μ-F4BDC)(H2O)6] (3) have been characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and optical measurements. Structural characterization revealed that compounds 1 and 2 present an interesting MOF architecture with extended rectangular cavities which are only filled with water molecules. On the other hand, compound 3 shows a much more complex topology with no apparent cavities. We discuss here the origins of such differences and highlight the crucial role of the Ln(III) ion nature for the topology of the CP. Compounds 1 and 2 now offer a playground to investigate the possible synergy between gas/solvent sorption and magnetic/luminescent properties of Ln-MOFs.

Structural diversity of cadmium coordination polymers based on an extended anilate-type ligand

“…Coordination polymerbased materials can serve as gas adsorbents, [46][47][48] luminescent agents, 9,49 electrochemical or photophysical sensors, 4,50 and electroconductive 5,[51][52][53][54][55][56][57][58] and magnetic materials. 29,59,60 The creation of new anilate-type ligands for the synthesis of CPs, 3,44,59 as well as the preparation of mixed-ligand CPs containing two anionic ligands, 49,[61][62][63][64][65][66][67] is a promising area of research, as it opens the possibility of synthesizing compounds with new topologies and properties. One of the prospective ditopic ligands for the synthesis of new derivatives is the closest analog of anilate ligands containing an extended π-system -4,4′-(1,4-phenylylenebis(azanylylidene))bis (3,6-di-tertbutyl-2-hydroxycyclohexa-2,5-dienone) (H 2 L).…”

“…The creation of new anilate-type ligands for the synthesis of CPs, 3,44,59 as well as the preparation of mixed-ligand CPs containing two anionic ligands, 49,61–67 is a promising area of research, as it opens the possibility of synthesizing compounds with new topologies and properties. One of the prospective ditopic ligands for the synthesis of new derivatives is the closest analog of anilate ligands containing an extended π-system – 4,4′-(1,4-phenylylenebis(azanylylidene))bis(3,6-di- tert -butyl-2-hydroxycyclohexa-2,5-dienone) ( H 2 L ).…”

Terbium and Europium Chlorocyananilate-Based 2D Coordination Polymers

“…Lanthanide-based Coordination Polymers (Ln-CPs) and Metal-Organic Frameworks (Ln-MOFs) have attracted considerable interest in material science thanks to their peculiar supramolecular architectures (extending in one, two or three dimensions: 1D, 2D and 3D), their versatile optical properties in the visible (Eu III and Tb III ) [ 1 , 2 , 3 ] and near-IR (NIR, for Nd III , Er III and Yb III ) regions, and also their unique magnetic (Ho III , Dy III and Tb III ) properties, due to their intrinsically high magnetic anisotropy, at the origin of interesting magnetic phenomena such as hard magnets or single-molecule magnets. By virtue of these features, they find applications in several applied fields, ranging from telecommunication and data storage to drug delivery, sensing and catalysis [ 4 , 5 , 6 , 7 ]. Among these materials, two-dimensional coordination polymers (2D CPs), containing self-assembling metal-ligand-based sheets mutually interacting through weak(er) non-covalent-type interactions as Van der Waals, dipolar and hydrogen-bonding, are of ever-growing interest in material chemistry, as their ultrathin nature favors unique optical, electronic and magnetic properties [ 8 , 9 , 10 ], as well as chemical processing and rheology, through swelling or exfoliation [ 11 , 12 ].…”

“…properties, due to their intrinsically high magnetic anisotropy, at the origin of interesting magnetic phenomena such as hard magnets or single-molecule magnets. By virtue of these features, they find applications in several applied fields, ranging from telecommunication and data storage to drug delivery, sensing and catalysis [4,5,6,7]. Among these materials, two-dimensional coordination polymers (2D CPs), containing self-assembling metalligand-based sheets mutually interacting through weak(er) non-covalent-type interactions as Van der Waals, dipolar and hydrogen-bonding, are of ever-growing interest in material chemistry, as their ultrathin nature favors unique optical, electronic and magnetic properties [8,9,10], as well as chemical processing and rheology, through swelling or exfoliation [11,12].…”

Photoluminescent Polymer Aerogels with R, G and B Emission

“…Due to their particular characteristics, these polymer complexes aerogels could be further developed in new approaches particularly relevant for various applications ranging from catalysis [27], water or air purification [28] to hydrogen storage [29] by using suitable cations coordinated with HEMA which are further processed in porous materials. Also, their MOF-like configuration [30,31] could also be an important argument for further developments and applications.…”