Crystal structure and Hirshfeld surface analysis of 3-cyanophenylboronic acid

In the title compound, C7H6BNO2, the mean plane of the –B(OH)2 group is twisted by 21.28 (6)° relative to the cyanophenyl ring mean plane. In the crystal, molecules are linked by O—H...O and O—H...N hydrogen bonds, forming chains propagating along the [101] direction. Offset π–π and B...π stacking interactions link the chains, forming a three-dimensional network. Hirshfeld surface analysis shows that van der Waals interactions constitute a further major contribution to the intermolecular interactions, with H...H contacts accounting for 25.8% of the surface

An Approach to the Use of Glycol Alkoxysilane–Polysaccharide Hybrids in the Conservation of Historical Building Stones

Stone consolidants have been widely used to protect historical monuments. Consolidants and hydrophobic formulations based on the use of tetraethoxysilane (TEOS) and alkylalkoxysilanes as precursors have been widely applied, despite their lack of solubility in water and requirement to be applied in organic media. In the search for a “greener” alternative based on silicon that has potential use in this field, the use of tetrakis(2-hydroxyethyl)silane (THEOS) and tris(2-hydroxyethyl)methyl silane (MeTHEOS) as precursors, due their high water solubility and stability, is proposed in this paper. It is already known that THEOS and MeTHEOS possess remarkable compatibility with different natural polysaccharides. The investigated approach uses the water-soluble silanes THEOS–chitosan and MeTHEOS–chitosan as a basis for obtaining hybrid consolidants and hydrophobic formulations for the conservation of siliceous and calcareous stones. In the case of calcareous systems, their incompatibility with alkoxysilanes is known and is expected to be solved by the developed hybrid consolidant. Their application in the conservation of building stones from historical and archeological sites from Guanajuato, México was studied. The evaluation of the consolidant and hydrophobic formulation treatment was mainly conducted by determining the mechanical properties and contact angle measurements with satisfactory results in terms of the performance and compatibility with the studied stones