Transformations of lead 1,3-propylenediaminetetraacetate to its MOF products for the selective adsorption of methanol

Abstract

Water soluble coordination polymer of potassium lead 1,3-propylenediaminetetraacetate {K 4 [Pb 2 (1,3-pdta) 2 ]•6H 2 O} n (1) and its insoluble products {[Pb(1,3-H 2 pdta)(H 2 O)]•2H 2 O} n (2), {[Pb 2 (1,3-pdta)(H 2 O) 4 ]•4H 2 O} n (3) and [Pb 2 (1,3-pdta)(H 2 O) 2 ] n (4) were obtained from the direct reactions of lead nitrate with 1,3-propylenediaminetetraacetic acid in different conditions (1,3-H 4 pdta = 1,3-propylenediaminetetraacetic acid). The former 1 could be converted to the insoluble products of {[Pb 2 (1,3-pdta)(H 2 O) 4 ]•4H 2 O} n (3) and [Pb 2 (1,3-pdta)(H 2 O) 2 ] n (4) in weak acidic solution. The complexes have been full characterized by EA, FT-IR, solution and solid state 13 C NMR spectra, thermogravimetric and structural analyses. Interestingly, 3 contains a unique (H 2 O) 26 cluster and a 5.2 Å pore after eliminating the guest water molecules, which exhibits reversible adsorption for methanol. This is confirmed by PXRD and solid state 13 C NMR analyses. Nano-confined methanol in microporous structure has been observed based on the large downfield shift of 13 C NMR signal ( 9.72 ppm), attributing to the methyl group in methanol.

Manganese(II), lead(II) and cadmium(II) coordination complexes containing a tetrazole-based acylamide ligand: synthesis and the influence of the metal ions on the structures

“…The Pb-O bond lengths are similar to those observed earlier (Hu et al, 2011). The Pb-N bond lengths vary from 2.257 (2) to 2.432 (2) Å , which are close to the Pb-N bond lengths reported previously for Pb II cations (Dai et al, 2016).…”

Complete multinuclear solid‐state NMR of metal‐organic frameworks: The case of α‐Mg‐formate

“…The use of 13 C SSNMR to investigate MOFs has become fairly common, particularly in recent years . Despite the widespread use of 13 C SSNMR, very challenging situations arise when many crystallographically distinct but otherwise chemically similar carbon centers are present, which gives rise to multiple overlapping 13 C resonances confined within a narrow chemical shift range that cannot be easily simulated or assigned, as in the case of α‐Mg‐formate …”