Robust Multifunctional Yttrium-Based Metal Organic Frameworks with Breathing Effect

authors	Firmino, ADG; Mendes, RF; Antunes, MM; Barbosa, PC; Vilela, SMF; Valente, AA; Figueiredo, FML; Tome, JPC; Paz, FAA
nationality	International
journal	INORGANIC CHEMISTRY
keywords	PROTON-CONDUCTION PROPERTIES; SOLID ACID CATALYSTS; COORDINATION POLYMERS; CARBONYL-COMPOUNDS; SINGLE-CRYSTAL; ACETALIZATION; PHOSPHONATE; LINKER; DIOLS; MOFS
abstract	Phosphonate- and yttrium-based metal-organic frameworks (MOFs), formulated as [Y(H(5)btp)]center dot 5.5H(2)O (1), [Y(H(5)btp)]center dot 2.5H(2)O (2), (H3O)[Y-2(H(5)btp)(H4btp)]center dot H2O (3), and [Y(H(5)btp)]center dot H2O center dot 0.5(MeOH) (4), were prepared using a green microwave-assisted synthesis methodology which promoted the self-assembly of the tetraphosphonic organic linker [1,1'-biphenyl]-3,3',5,5'-tetrayltetrakis(phosphonic acid) (H(8)btp) with Y3+ cations. This new family of functional materials, isolated in bulk quantities, exhibits a remarkable breathing effect. Structural flexibility was thoroughly studied by means of X-ray crystallography, thermogravimetry, variable-temperature X-ray diffraction, and dehydration and rehydration processes, ultimately evidencing a remarkable reversible single-crystal to single-crystal (SC-SC) transformation solely through the loss and gain of crystallization solvent molecules. Topologically, frameworks remained unaltered throughout this interconversion mechanism, with all compounds being binodal 6,6-connected network with a Schafli symbol of {4(13).6(2)}{4(8).6(6).8}. Results show that this is one of the most stable and thermally robust families of tetraphosphonate-based MOFs synthesized reported to date. Porous materials 2 and 3 were further studied to ascertain their performance as heterogeneous catalysts and proton conductors, respectively, with outstanding results being registered for both materials. Compound 2 showed a 94% conversion of benzaldehyde into (dimethoxymethyl)benzene after just 1 h of reaction, among the best results registered to date for MOF materials. On the other hand, the protonic conductivity of compound 3 at 98% of relative humidity (2.58 x 10(-2) S cm(-1)) was among the highest registered among MOFs, with the great advantage of the material to be prepared using a simpler and sustainable synthesis methodology, as well as exhibiting a good stability at ambient conditions (temperature and humidity) over time when compared to others.
publisher	AMER CHEMICAL SOC
issn	0020-1669
isbn	1520-510X
year published	2017
volume	56
issue	3
beginning page	1193
ending page	1208
digital object identifier (doi)	10.1021/acs.inorgchem.6b02199
web of science category	Chemistry, Inorganic & Nuclear
subject category	Chemistry
unique article identifier	WOS:000393630300024