Coordination Polymers Based on a Biphenyl Tetraphosphonate Linker: Synthesis Control and Photoluminescence

authors	Firmino, ADG; Mendes, RF; Ananias, D; Barbosa, JS; Tome, JPC; Paz, FAA
nationality	International
journal	MOLECULES
author keywords	metal-organic framework; crystal structure; photoluminescence
keywords	METAL-ORGANIC FRAMEWORKS; CATALYSTS; NETWORKS
abstract	In this work, we used the rigid tetrapodal organic linker, [1,1'-biphenyl]-3,3',5,5'-tetrayltetrakis(phosphonic acid) (H(8)btp), for the preparation of two lanthanide-organic framework families of compounds: layered [Ln(7)(H(5)btp)(4)(H(5.5)btp)(2)(H(6)btp)(2)(H2O)(12)]center dot 23.5H(2)O center dot MeOH [where Ln(3+) = Eu3+ (1Eu) and Gd3+ (1Gd)], prepared using microwave-irradiation followed by slow evaporation; 3D [Ln(4)(H(3)btp)(H(4)btp)(H(5)btp)(H2O)(8)]center dot 3H(2)O [where Ln(3+) = Ce3+ (2Ce), Pr3+ (2Pr), and Nd3+ (2Nd)], obtained from conventional hydro(solvo)thermal synthesis. It is shown that in this system, by carefully selecting the synthetic method and the metal centers, one can increase the dimensionality of the materials, also increasing structural robustness (particularly to the release of the various solvent molecules). Compound 1 is composed of 2D layers stacked on top of each other and maintained by weak pi-pi interactions, with each layer formed by discrete 1D organic cylinders stacked in a typical brick-wall-like fashion, with water molecules occupying the free space in-between cylinders. Compound 2, on the other hand, is a 3D structure with small channels filled with crystallization water molecules. A full solid-state characterization of 1 and 2 is presented (FT-IR spectroscopy, SEM microscopy, thermogravimetric studies, powder X-ray diffraction and thermodiffractometry). The photoluminescence of 1Eu was investigated.
publisher	MDPI
isbn	1420-3049
year published	2020
volume	25
issue	8
digital object identifier (doi)	10.3390/molecules25081835
web of science category	Biochemistry & Molecular Biology; Chemistry, Multidisciplinary
subject category	Biochemistry & Molecular Biology; Chemistry
unique article identifier	WOS:000534617500031