A Metal Organic Framework (MOF) Containing Nitrogen Donor Ligands For Highly Efficient Catalysis of Organic Reactions

Interests: Chemical Synthesis

Published: December 17, 2019

Lead Inventor: Wenbin Lin

Print or Save to PDF

SUMMARY

Pyridyl moieties are highly useful in catalytic applications because of their robust redox stability, metallic coordination versatility, and functionalization ease. However, their application is limited due to poor solubility and susceptibility to degradation. As such, catalysts that address these limitations would have a high utility in a wide range of organic reactions.
Metal organic frameworks (MOFs) have previously been shown to mitigate some of the disadvantages of solid-state catalysts, but have only been applied in limited applications, and never with nitrogen donating moieties. The inventors synthesized UiO-type MOFs postsynthetically metalated with Ir or Pd. The MOFs are novel in that they contain a 2,2’-bipyridial functional fragment. The catalysts have a particle size of 300nM, surface areas of 365m2/g (Ir metalated) and 457.5m2/g (Pd metalated), and pore sizes of 5.6Å (Ir metalated) and 6.7Å (Pd metalated).
The invention is a novel metal organic framework catalyst containing UiO and a 2,2’-bipyridial functional fragment, postsynthetically metalated with Ir or Pd. The catalyst is amenable for use in a range of organic reactions with high regioselectivity.
The inventors validated the MOF in several organic reactions, including: borylation of aromatic C-H bonds, ortho-silyation of benzylicsilyl ethers, and dehydration of substituted cyclohexenes. The yields of each reaction were at least 83% and the catalyst was shown to be recyclable up to 20 times with no metallic leaching or catalyst structural changes.

FIGURE

(A)Schematic illustration of the metal organic framework catalyst (MOF) with the UiO (zirconium) shown in light blue, the 2,2’-bipyridial functional fragment shown in stick formation, and the orange sphere depicting the postsynthetic metalation (Ir or Pd). (B) GC conversion data for C-H borylation of m-xylene using either the MOF catalyst (black line) or the homogeneous control catalyst (red line), both catalysts at 0.5 mol %. (C) GC conversion data for the ortho-silyation of xylene using either the MOF catalyst (black line) or the homogeneous control catalyst (red line), both catalysts at 0.1mol%.

ADVANTAGES

Higher yields than comparable homogeneous catalyst
Highly recyclable without leaching or loss of structure
Highly tunable for a wide change of organic reactions (can change central metal)
Highly regioselective

APPLICATIONS

Organic chemistry synthesis
Medicinal chemistry
Fine chemical synthesis

PUBLICATIONS

Manna, K; et al. Postsynthetic metalation of bipyridyl-containing metal-organic frameworks for highly efficient catalytic organic transformations. J Am Chem Soc. 2014 May 7;136(18):6566-9.

US Nationalized PCT: PCT/US15/23387