ABSTRACT
Phosphine metal-organic frameworks (P-MOFs) are crystalline porous coordination polymers that contain phosphorus functional groups within their pores. We present the use of X-ray absorption spectroscopy (XAS) at the P K-edge to determine the phosphine to phosphine oxide ratio in two P-MOFs with MIL-101 topology. The phosphorus oxidation state is of particular interest as it strongly influences the coordination affinity of these materials for transition metals. This method can determine the oxidation state of phosphorus even when the material contains paramagnetic nuclei, differently from NMR spectroscopy. We observed that phosphine in LSK-15 accounts for 72 ± 4% of the total phosphorus groups and that LSK-12 contains only phosphine oxide.
Subject(s)
Organometallic Compounds/chemistry , Phosphines/chemistry , X-Ray Absorption Spectroscopy , Magnetic Resonance Spectroscopy , Oxides/chemistry , Phosphorus/chemistry , Polymers/chemistry , Porosity , X-Ray DiffractionABSTRACT
PtCu- and PdCu-mordenite allow for isothermal reaction at 200 °C for the stepwise methane to methanol conversion with comparably high yields. In contrast to traditional Cu-zeolites, these materials are more reactive under isothermal conditions than after high temperature activation.
ABSTRACT
The deposition of gold on silica tends to give large particles when using conventional techniques. We report the preparation of 0.8 ± 0.2 nm particles on a modified SBA-15 support. The method involves the functionalization of silica with amine groups and deposition of gold at basic pH. These catalysts are highly active and selective in the dehydrogenation of formic acid.