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Our research focuses on the synthesis, characterization and application of inorganic (boron based) and inorganic-organic hybrid solids. Our focus for several years has been on the development of new carborane based ligands or linkers for preparing a variety of molecular, supramolecular and polymeric materials. The following are the main areas of interest in this research.

  1. New concepts in Metal-Organic Framework (MOF) Chemistry

Angew. Chem., Int. Ed., 2016, DOI: 10.1002/anie.201609295R1.

Metal-organic frameworks (MOFs) or coordination polymers (CPs) are a class of materials that combine organic ligands and metal ions to generate porous materials with defined topologies. Although MOFs are very attractive for many applications, one of their major drawbacks is their low hydrolytic stability preventing their use for many industrial processes such as the direct capture of CO2 from flue gas, water purification and others. We have recently communicated the first example that uses a non-carboxylic derivative of o-carborane as a linker to form a porous hydrophobic and water stable Zn(II)-based CP (oCB-MOF-1; Figure 1). Most interestingly, oCB-MOF-1 surface hydrophobicity/hydrophilicity can be switched by chemical treatment (Figure 2).

ocbmof1 mechanism
Figure 1. a) oCB-L linker; b) BDC linker; c) Zn4(O)2(OOC)4 cluster; d) Pillaring µ2-oCB-L linkers (blue) connect Zn4(bdc)2 layers (green), giving rise to a 3D structure. Carborane cores are represented in dark blue; 1D channels, formed by connected cavities (in yellow), run along the c axis. Color code (a-c): B (pink), O (red), C (gray), H (white), Zn (violet). Figure 2. Mechanism proposed for the switchable surface hydrophobicity-hydrophilicity of oCB-MOF-1. Pillaring oCB-L linkers are represented in blue and Zn4(bdc)2 layers in green. Contact angle images of oCB-MOF-1 before treatment (top, left), after immersion in a DMF solution containing 10 equivalents of NaOH (top, middle) and after immersion in H2O (top. right).

 

  1. Multifunctional Molecular Materials

Inorg. Chem. 2014, 53, 9284-9295.

Synthesis and structural studies of o– and m-carborane-based NBN pincer palladium complexes are described, along with density functional theory (DFT) calculations conducted to gain more insight into these new carboranyl motifs. Catalytic applications of (oCB-L1)Pd and (mCB-L1)Pd have shown the complexes are good catalyst precursors in Suzuki coupling in water and with infinitesimal amounts of catalyst loadings.

 

 

Chem. Eur. J. 2014, 20, 1081-1090.

Three significantly bulky and chiral carboranylpyridinealkoxide ligands, rather than the expected two, bridge two FeIII centers affording an unusual unsymmetric complex that combines magnetism, chiroptical and second-order optical nonlinear properties. Enantiomerically pure ligands afford the corresponding configurationally stable enantiopure dinuclear FeIII complexes.

 

 

Others: Crystals 2016, 6, 50;Inorg. Chim. Acta 2016, 448, 97-103; Cryst. Growth Des. 2012, 12, 5720-5736.

 

  1. Crystal Engineering

Cryst. Growth Des. 2015, 15, 935.

The comparison of twenty X-ray structures for chiral 2-pyridylalcohols –either in racemic or enantiopure forms– that form O–H∙∙∙N hydrogen bonded homochiral 21-helical networks, reveals a clear relationship between the torsion angle of the hydrogen bond donor and acceptor groups in these molecules and the hydrogen bonded supramolecular helices formed in the solid state.

 

Others: Cryst. Growth Des. 2013, 13, 1473-1484; CrystEngComm. 2011, 13, 5788-5806; CrystEngComm. 2010, 12, 4109-4123;Chem. Eur. J. 2007, 13, 2493; J. Am. Chem. Soc. 2005, 127, 15976-15982.

 

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