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A clear understanding and appreciation of noncovalent interactions, especially hydrogen bonding, are vitally important to students of chemistry and the life sciences, including biochemistry, molecular biology, pharmacology, and medicine. The opportunities afforded by the IsoStar knowledge base of intermolecular interactions to enhance the educational experience of students are summarized. Derived from experimentally determined crystal structures in the Cambridge Structural Database and Protein Data Bank, IsoStar contains geometrical and spatial information on nearly 30,000 different types of interactions in small molecules and proteins. (Contains 2 tables and 6 figures.)

Parts 1 and 2 of this series described the educational value of experimental three-dimensional (3D) chemical structures determined by X-ray crystallography and retrieved from the crystallographic databases. In part 1, we described the information content of the Cambridge Structural Database (CSD) and discussed a representative teaching subset of ca. 500 CSD structures that have been selected for their educational relevance. In part 2, we exemplified the value of the CSD teaching subset by describing four worked examples of their use in a teaching context. Although the CSD teaching subset and its associated learning modules provide a major resource for chemical educators, there are many cases where the full CSD System, now covering more than 500,000 crystal structures, is essential to make an educational point. This is particularly true when introducing students to variance in real experimental observations, for example, where many hundreds of observations are required to generate statistically meaningful trends from the structural data or simply to introducing students to the search and manipulation of data that are commonly available in large chemical and biochemical databases. Here, we describe the complete CSD System and its associated software and highlight the extended range of discovery-based learning opportunities this affords. (Contains 1 table and 5 figures.) [For Part 2, see EJ918551.]

Parts 1 and 2 of this series described the educational value of experimental three-dimensional (3D) chemical structures determined by X-ray crystallography and retrieved from the crystallographic databases. In part 1, we described the information content of the Cambridge Structural Database (CSD) and discussed a representative teaching subset of ca. 500 CSD structures that have been selected for their educational relevance. In part 2, we exemplified the value of the CSD teaching subset by describing four worked examples of their use in a teaching context. Although the CSD teaching subset and its associated learning modules provide a major resource for chemical educators, there are many cases where the full CSD System is essential to make an educational point. In part 3, we describe the complete CSD System and its associated software and highlight the extended range of discovery-based learning opportunities this affords. Here, we illustrate a number of teaching examples that take advantage of the massive structural information content of the complete CSD System to broaden and enhance the chemical education experience, including, for example, studies of mean molecular dimensions, stereochemistry and conformations, metal coordination sphere geometries, hydrogen bonding and other supramolecular phenomena, and reaction pathways. (Contains 16 figures and 1 table.) [For Part 3, see EJ938990.]

A series of online interactive teaching units have been developed that illustrate the use of experimentally measured three-dimensional (3D) structures to teach fundamental chemistry concepts. The units integrate a 500-structure subset of the Cambridge Structural Database specially chosen for their pedagogical value. The units span a number of key chemical concepts (aromaticity, ring strain and conformation, stereochemistry and chirality, VSEPR, and hapticity) and guide students via a Web-based interface to visualize and interact with a diverse range of molecules. The units were designed to help students develop a visual understanding of 3D chemical structure and gain an appreciation of the unique advantages afforded by working with experimentally measured data. (Contains 10 figures and 1 table.)

Low-temperature neutron diffraction was utilized to determine the crystal structure of 2- and 3-aminophenols and their tetrahedral hydrogen-bonded networks. The 2- and 3-aminophenols are composed of N-H...pi bonds that are located in electron-rich aromatic rings. The crystal structure of 2-aminophenol was also composed of phenyl rings that were arranged in a herringbone fashion with a T-shaped geometry.

The structure of 2-ethynyladamantan-1-ol is analyzed using neutron diffraction techniques to determine the types of hydrogen bonds it contains. Results indicate the presence of an unusual hydrogen bond of the type O-H...pi, aside from the more common O-H...O and C-H...O bonds. The novel bond points to its center, rather than the alkynic carbon atoms, when it is directed towards a -C=C- bond. A very short and straight C-H...0 bond is also shown to be present.

Searches of the Cambridge Structural Database were carried out to investigate the intermolecular forces between electronegative atoms of nitrogen and oxygen in different hybridization states and carbon-bonded halogen atoms. The searches demonstrated that electronegative atoms preferred to interact with chlorine, iodine and bromine with specific directionality and 'interatomic distances less than the sum of the the van der Waals radii.'

It is believed that knowledge of the three-dimensional (3D) nature of chemical compounds is fundamental to the education of chemists. Because of this, the use of experimentally measured 3D structure as opposed to idealized computationally generated models would be helpful. Information about a teaching subset which was taken from the Cambridge Structural Database is also provided.