Synthesis, Structures, and Sorption Properties of Two New Metal-Organic Frameworks Constructed by the Polycarboxylate Ligand Derived from Cyclotriphosphazene.

Jing-Hua Han,Bing-Qian Hu,Hao Liang,Bao Li,Qiang Zhao,Fan Yu,Tangming Li

doi:10.1021/acsomega.1c02492

Jing-Hua Han, Bing-Qian Hu + Show 5 more

Open Access

https://doi.org/10.1021/acsomega.1c02492

Copy DOI

Abstract

Solvothermal reactions of hexakis(4-carboxyphenoxy)cyclotriphospazene (H6L1) with copper ions in DMF/H2O produced one complex, {[Cu6(L1)2(OH)(H2O)3]·guest}n (1), but with copper ions and auxiliary rigid 4,4-bipyridine (bpy) produced another new complex, namely, {[Cu3(L1)(bpy)(H2O)6]·guest}n (2). These complexes had been characterized by IR spectroscopy, elemental analysis, and X-ray structural determination. 1 exhibits a 3D anionic structure with the binodal 4,8-connected network with Schläfli symbol {46}2{49·618·8}, consisting of Cu6 clusters and L1 ligands. In contrast, complex 2 possesses a different 3D network with trinodal 3,4,6-c topology with Schläfli symbol {4·62}2{42·66·85·102}{64·8·10}. In these two complexes, the semirigid hexacarboxylate ligands adopt distinct conformations to connect metal ions/clusters, which must be ascribed to the addition of the auxiliary rigid ligand in reaction systems. In addition, gas absorption properties of 1 and 2 including CO2 and N2 were further investigated.

Highlights

Great attention focused on metal−organic frameworks (MOFs) originated from the aesthetics network and their versatile potential applications.[1−5] The composition of MOFs definitely contains metal nodes usually named secondary building units (SBUs) and organic spacer.[1−5] The rational construction of MOFs depends on versatile conditions.[6−11] controllable building of MOFs still poses a difficult challenge
Compared to the reported highly connected carboxylates referred to aromatic templates, our group explored a hexacarboxylate ligand, hexakis(4-carboxyphenoxy)cyclotriphosphazene (H6L1), derived from a renowned inorganic heterocyclic ring to act as the central scaffold and used to construct new MOFs
Two MOFs using the flexible hexacarboxylate ligand derived from a renowned inorganic heterocyclic cyclotriphosphazene have been successfully synthesized and structurally characterized

Summary

■ INTRODUCTION

Great attention focused on metal−organic frameworks (MOFs) originated from the aesthetics network and their versatile potential applications.[1−5] The composition of MOFs definitely contains metal nodes (ions/clusters) usually named secondary building units (SBUs) and organic spacer (strut or bridging linker).[1−5] The rational construction of MOFs depends on versatile conditions.[6−11] controllable building of MOFs still poses a difficult challenge. In terms of rational assembly, proper utilization of organic linkers would be of one facile method to tune the topologies.[12] The configuration and connection mode of the selected ligands are the key points to determine the final structure of MOFs.[12] For example, the utilization of versatile rigid polycarboxylate ligands would determine the variable MOFs.[13] coordination assemblies containing highly connected flexible carboxylate ligands are relatively rare. These new MOFs are characterized by elemental analysis, IR spectra, and X-ray crystallography

■ RESULTS AND DISCUSSION

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES