An azobenzene-containing metal–organic framework as an efficient heterogeneous catalyst for direct amidation of benzoic acids: synthesis of bioactive compounds

Abstract

An azobenzene-containing zirconium metal-organic framework was demonstrated to be an effective heterogeneous catalyst for the direct amidation of benzoic acids in tetrahydrofuran at 70 °C. This finding was applied to the synthesis of several important, representative bioactive compounds.

Amino acids as highly efficient modulators for single crystals of zirconium and hafnium metal–organic frameworks

“…24 A recent catalytic study reported an acetic acid (525 equivalents) modulated synthesis of Zr-L7 that resulted in micron-sized particles. 30 Isolation of discrete octahedral single crystals of Zr-L7 and Zr-L8 was possible using four equivalents of L-proline and one equivalent of HCl in a solvothermal synthesis at 100 C for 48 h in DMF. During repeated syntheses, it was noted that order of addition was key to gaining large single crystals; addition of HCl to a pre-sonicated mixture of the other reagents provided optimal results.…”

Atomic/Molecular Layer Deposited Iron–Azobenzene Framework Thin Films for Stimuli‐Induced Gas Molecule Capture/Release

“…Theb ackswitching is driven by visible light illumination or thermal relaxation. [11,12] These efforts can be divided into three groups depending on whether the azobenzene moiety is accommodated as 1) the actual framework linker, [13,14] 2) as ide-group pendant to the linker, [15,16] or 3) ag uest species in the pores incorporated either during the synthesis or through ap ostsynthesis treatment. [11,12] These efforts can be divided into three groups depending on whether the azobenzene moiety is accommodated as 1) the actual framework linker, [13,14] 2) as ide-group pendant to the linker, [15,16] or 3) ag uest species in the pores incorporated either during the synthesis or through ap ostsynthesis treatment.…”

“…[9,10] Introduction of azobenzene moieties in porous MOF-like materials has already been challenged in recent studies. [11,12] These efforts can be divided into three groups depending on whether the azobenzene moiety is accommodated as 1) the actual framework linker, [13,14] 2) as ide-group pendant to the linker, [15,16] or 3) ag uest species in the pores incorporated either during the synthesis or through ap ostsynthesis treatment. [17,18] Thef irst alternative would be truly exciting but difficult to realize;t he challenges arise from the fact that azobenzene is an integral part of ar igid crystal structure in which the trans-cis transformation either does not occur owing to the lack of free space,o ro ccurs but destroys the crystal lattice in an irreversible manner.…”

Atomic/Molecular Layer Deposited Iron–Azobenzene Framework Thin Films for Stimuli‐Induced Gas Molecule Capture/Release

“…Introduction of azobenzene moieties in porous MOF‐like materials has already been challenged in recent studies . These efforts can be divided into three groups depending on whether the azobenzene moiety is accommodated as 1) the actual framework linker, 2) a side‐group pendant to the linker, or 3) a guest species in the pores incorporated either during the synthesis or through a post‐synthesis treatment . The first alternative would be truly exciting but difficult to realize; the challenges arise from the fact that azobenzene is an integral part of a rigid crystal structure in which the trans – cis transformation either does not occur owing to the lack of free space, or occurs but destroys the crystal lattice in an irreversible manner …”