Creation of controlled brønsted acidity on a zeotypic mesoporous chromium(III) carboxylate by grafting water and alcohol molecules

This paper reports a new way of modulating the strength of the Bronsted acid sites of a porous solid. Our approach consists of the grafting of various polar molecules (H2O, CD3OH, CF3CH2OH, and (CF3)2CHOH) on MIL-100(Cr), a mesoporous crystallized chromium carboxylate with accessible unsaturated metal sites. We demonstrate, using infrared spectroscopy, that all these compounds do coordinate on the coordinatively unsaturated Cr3+ sites. This generates controlled Bronsted acid sites whose strength, measured by CO adsorption at 100 K, depends on the nature of the adsorbate. It can vary from H0 = −3 (CD3OH) to −8 ((CF3)2CHOH).

[1]  Gérard Férey,et al.  Microporous Solids: From Organically Templated Inorganic Skeletons to Hybrid Frameworks...Ecumenism in Chemistry , 2001 .

[2]  K. Lillerud,et al.  Interaction of Hydrogen with MOF-5. , 2005, The journal of physical chemistry. B.

[3]  J. Lavalley,et al.  Brnsted acidity of extraframework debris in steamed Y zeolites from the FTIR study of CO adsorption , 1998 .

[4]  K. Góra-Marek,et al.  IR and NMR studies of mesoporous alumina and related aluminosilicates , 2005 .

[5]  K. Thomas,et al.  FTIR studies of unusual OH groups in steamed HNaY zeolites : preparation and acid properties , 2001 .

[6]  C. Serre,et al.  A Chromium Terephthalate-Based Solid with Unusually Large Pore Volumes and Surface Area , 2005, Science.

[7]  Gérard Férey,et al.  A route to the synthesis of trivalent transition-metal porous carboxylates with trimeric secondary building units. , 2004, Angewandte Chemie.

[8]  E. Selli,et al.  Comparison between the surface acidity of solid catalysts determined by TPD and FTIR analysis of pre-adsorbed pyridine , 1999 .

[9]  C. Serre,et al.  Investigation of acid sites in a zeotypic giant pores chromium(III) carboxylate. , 2006, Journal of the American Chemical Society.

[10]  C. Lamberti,et al.  Local Structure of Framework Cu(II) in HKUST-1 Metallorganic Framework: Spectroscopic Characterization upon Activation and Interaction with Adsorbates , 2006 .

[11]  Jinho Oh,et al.  A homochiral metal–organic porous material for enantioselective separation and catalysis , 2000, Nature.

[12]  M. O'keeffe,et al.  Design and synthesis of an exceptionally stable and highly porous metal-organic framework , 1999, Nature.

[13]  Françoise Maugé,et al.  2,6-dimethylpyridine as a probe of the strength of Brønsted acid sites: study on zeolites. Application to alumina. , 2005, Physical chemistry chemical physics : PCCP.

[14]  J. Lavalley,et al.  Interprétation des spectres de vibration d'alcools de type CX3CH2OH (X: F, Cl, Br) dans la région 1500-450 cm−1. Etude de la vibration δ(OH) , 1976 .

[15]  Avelino Corma,et al.  State of the art and future challenges of zeolites as catalysts , 2003 .

[16]  Gérard Férey,et al.  Prospects for Giant Pores , 1999, Science.

[17]  G. Busca,et al.  Microcalorimetric and Fourier transform infrared spectroscopic studies of methanol adsorption on alumina , 1985 .

[18]  A. Burneau.  Near infrared spectroscopic study of the structures of water in proton acceptor solvents , 1990 .

[19]  O. Cairon,et al.  Quantitative FTIR studies of hexagonal and cubic faujasites by pyridine and CO adsorption Numbers and relative acidity of the HF and LF zeolitic hydroxy groups , 1998 .

[20]  K. Thomas,et al.  Acid-catalysed benzene hydroconversion using various zeolites: Brönsted acidity, hydrogenation and side-reactions , 2003 .

[21]  J. Bordado,et al.  Infrared spectroscopic study of the acid properties of dealuminated BEA zeolites , 2003 .

[22]  T. Dziembowska,et al.  Infrared and Raman investigation of the liquid addition compounds BF3-CH3OH and BF3-2CH3OH , 1978 .

[23]  Michael O'Keeffe,et al.  Hydrogen Storage in Microporous Metal-Organic Frameworks , 2003, Science.

[24]  Maw-Tien Lee,et al.  Activated-carbon-supported NaOH for removal of HCl from reformer process streams , 2003 .

[25]  J. Murto,et al.  Fluoroalcohols—XX: Infrared and Raman spectra of hexafluoro-2-propanol and its deuterated analogues , 1973 .

[26]  Y. Kawazoe,et al.  Highly controlled acetylene accommodation in a metal–organic microporous material , 2005, Nature.