Halogen and Hydrogen Bonding in Multicomponent Crystals of Tetrabromo-1H-Benzotriazole
Michele Baldrighi,
Pierangelo Metrangolo,
Tullio Pilati,
Giuseppe Resnati,
Giancarlo Terraneo
Affiliations
Michele Baldrighi
Laboratory of Nanostructured Fluorinated Materials (NFMLab), Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Politecnico di Milano, via L. Mancinelli 7, I-20131 Milano, Italy
Pierangelo Metrangolo
Laboratory of Nanostructured Fluorinated Materials (NFMLab), Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Politecnico di Milano, via L. Mancinelli 7, I-20131 Milano, Italy
Tullio Pilati
Laboratory of Nanostructured Fluorinated Materials (NFMLab), Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Politecnico di Milano, via L. Mancinelli 7, I-20131 Milano, Italy
Giuseppe Resnati
Laboratory of Nanostructured Fluorinated Materials (NFMLab), Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Politecnico di Milano, via L. Mancinelli 7, I-20131 Milano, Italy
Giancarlo Terraneo
Laboratory of Nanostructured Fluorinated Materials (NFMLab), Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Politecnico di Milano, via L. Mancinelli 7, I-20131 Milano, Italy
4,5,6,7-Tetrabromo-1H-benzotriazole (TBBT) is still considered a reference inhibitor of casein kinase II (CK2), a valuable target for anticancer therapy, even though the poor solubility in water of this active pharmaceutical ingredient (API) has prevented its implementation in therapy. We decided to explore the interactions preferentially formed by TBBT in crystalline solids in order to obtain information helpful for the development of new TBBT cocrystals possibly endowed with improved bioavailability. In this paper, we describe the synthesis and the structural characterization of the TBBT methanol solvate and of the TBBT salt with N,N,N’,N’-tetramethylethylenediamine. It is shown that TBBT can give rise to several competing interactions. This API is clearly a good halogen bond (XB) donor, with bromine atoms adjacent to the triazole ring possibly better donors than the two others. TBBT is also a good hydrogen bond (HB) donor, with the triazole hydrogen forming an HB with the acceptor or being transferred to it. Interestingly, one of the triazole nitrogens was proven to be able to work as a hydrogen bond acceptor.
