Copper Benzene Tricarboxylate Research Articles

Copper Benzene Tricarboxylate Metal–Organic Framework with Wide Permanent Mesopores Stabilized by Keggin Polyoxometallate Ions

Porous solids with organized multiple porosity are of scientific and technological importance for broadening the application range from traditional areas of catalysis and adsorption/separation to drug release and biomedical imaging. Synthesis of crystalline porous materials offering a network of uniform micro- and mesopores remains a major scientific challenge. One strategy is based on variation of synthesis parameters of microporous networks, such as, for example, zeolites or metal-organic frameworks (MOFs). Here, we show the rational development of an hierarchical variant of the microporous cubic Cu(3)(BTC)(2) (BTC = 1,3,5-benzenetricarboxylate) HKUST-1 MOF having strictly repetitive 5 nm wide mesopores separated by uniform microporous walls in a single crystal structure. This new material coined COK-15 (COK = Centrum voor Oppervlaktechemie en Katalyse) was synthesized via a dual-templating approach. Stability was enhanced by Keggin type phosphotungstate (HPW) systematically occluded in the cavities constituting the walls between the mesopores.

Manufacture of dense coatings of Cu 3(BTC) 2 (HKUST-1) on α-alumina

By a seeding approach coatings of copper benzene tricarboxylate (Cu 3(BTC) 2, also known as HKUST-1) are obtained on α-alumina. The obtained crystal densities, order and intergrowth improve the best results reported up to now in the literature for any metal-organic framework material. The effect of synthesis conditions on the morphology and crystal size of Cu 3(BTC) 2 was determined to optimize the strategies for the synthesis of continuous layers. Seeding with coordination polymers of different morphology resulted in control of crystal growth of the coating. Two seeding suspensions yielded the best intergrowth of crystals. Spin-coating the support with a one-dimensional Cu(II)–BTC coordination polymer suspension resulted in a high density coating with randomly oriented crystals of ∼2 μm, while using amorphous MOF precursors (proto-MOFs) as seeds, coatings with crystals of ∼5 μm were obtained.

High-Capacity Hydrogen and Nitric Oxide Adsorption and Storage in a Metal−Organic Framework

Gas adsorption experiments have been carried out on a copper benzene tricarboxylate metal-organic framework material, HKUST-1. Hydrogen adsorption at 1 and 10 bar (both 77 K) gives an adsorption capacity of 11.16 mmol H2 per g of HKUST-1 (22.7 mg g(-)1, 2.27 wt %) at 1 bar and 18 mmol per g (36.28 mg g(-)1, 3.6 wt %) at 10 bar. Adsorption of D2 at 1 bar (77 K) is between 1.09 (at 1 bar) and 1.20(at <100 mbar) times the H2 values depending on the pressure, agreeing with the theoretical expectations. Gravimetric adsorption measurements of NO on HKUST-1 at 196 K (1 bar) gives a large adsorption capacity of approximately 9 mmol g(-1), which is significantly greater than any other adsorption capacity reported on a porous solid. At 298 K the adsorption capacity at 1 bar is just over 3 mmol g(-1). Infra red experiments show that the NO binds to the empty copper metal sites in HKUST-1. Chemiluminescence and platelet aggregometry experiments indicate that the amount of NO recovered on exposure of the resulting complex to water is enough to be biologically active, completely inhibiting platelet aggregation in platelet rich plasma.