Portal de Periódicos da CAPES

Hydrogen Bridges in Crystal Engineering: Interactions without Borders

2002; American Chemical Society; Volume: 35; Issue: 7 Linguagem: Inglês

10.1021/ar010054t

1520-4898

Gautam R. Desiraju,

Molecular Sensors and Ion Detection

A hydrogen bond, X−H···A, is an interaction wherein a hydrogen atom is attracted to two atoms, X and A, rather than just one and so acts like a bridge between them. This attraction always increases with increasing electronegativity of X and A, and in the classical view all hydrogen bonds are highly electrostatic and sometimes even partly covalent. Gradually, the concept of a hydrogen bond became more relaxed to include weaker interactions, provided some electrostatic character remains. In the limit, these weak hydrogen bonds have considerable dispersive−repulsive character and merge into van der Waals interactions. A great variety of hydrogen bonds are observed in the solid state and the aim of this article is to highlight some features common to all these bonds and further to suggest that the term hydrogen bridge is perhaps a better descriptor for them. Such a description recognizes an interaction without borders and one that admits of much variation in its relative covalent, electrostatic, and van der Waals content.