Chemical information tertiary sources

The literature of chemistry and associated fields has iacreased enormously siace 1980. Kstahlishment of subspecialties and newly defined disciplines as well as iacreased research output have led to an explosion of journals, books, and on-line databases, all of which attempt to capture, record, and disseminate this plethora of knowledge (1). Tertiary reference tools ia chemistry and technology (eg, KJrk-Othmer, 4th ed.) help track the primary Hterature. Excellent references that discuss basic chemical information tools are The Titerature Matrix of Chemistry (1), Chemical Information Sources (2), and Mow to Find Chemical Information (3). 

The Chemical Information Sources Wiki (http //cheminfo. informatics.indiana.edu/cicc/cis/index.php/Main Page) is a guide to the many sources of reference materials available for those with questions related to chemistry. The site includes information on primary, secondary, and tertiary pubheation sources, chemical information databases, physical property information, chemical patent searching, and molecular visualization tools and sites. The material is based on an undergraduate course offered for many years in the Indiana University Department of Chemistry by Gary Wiggins. 

Monographs, reference books, and encyclopedias, e.g., Ullmann s Encyclopedia of Industrial Chemistry, the Kirk-Othmer Encyclopedia of Chemical Technology, or the Encyclopedia of Computational Chemistry are included in this type of literature, which is furthest from the primary literature as concerns time and content. In most cases, tertiary literature summarizes a topic with information from different sources, and additionally evaluates the contents. 

Besides the NOE, the NMR technique offers other information that can also be used in structure determination. Spin-spin coupling constants are a traditional source of such information, and it is becoming increasingly clear that the chemical shifts in proteins and nucleic acids can often give direct information on the secondary and tertiary structure since they depend upon the local environment. This additional NMR information can be used at several levels. Coupling constant information is often converted to dihedral angle constraints and used in a manner similar to the distance constraints derived from NOE information. Because of the complexity of the interactions that influence the chemical shift, this information is more useful at the final structure refinement stage, where the overall structure has already been determined. 

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