Cambridge Crystallographic Database study

Analysis of intermolecular interactions in the crystal structures of oxime molecules has been used to answer that question. In all available complex structures with one central metal ion we found no coordinative bonds from the oxime oxygen to the metal, but exclusively coordination between the nitrogen atom and the metal ion (data were retrieved from the Cambridge Crystallographic Database [14]). In a comprehensive study Bohm et al. investigated complexes of oxazoles, methoxypyridines, and oxime ethers with water [15]. On the basis of interaction energies obtained... 

The crystal structure of aspirin was first determined by Wheatley in 1964 and was refined later, in 1985, by Kim and coworkers. Its crystal structure data can be obtained from the Cambridge Crystallographic Database. The key features of the crystal structure of aspirin are shown in Figure 2. Quite recently, the potential energy surface of aspirin was studied using the B3LYP/6-31G(d) method and all its nine conformational isomers were located . 

Coordinates for some structures determined from X-ray diffraction studies were obtained using the Cambridge Crystallographic Database, implemented through... 

The development of the structural study of CyDs in the last century has been summarized in several reviews [1-7]. In 1942, the crystallographic method was first applied to CyDs to determine molecular weight [8j. James et al. proposed a packing structure [9] for several crystalline complexes of a-CyD with small guest molecules in 1959. Preliminary crystallographic data of y -CyD complexes with benzene derivatives were reported in 1968 [10]. The crystal structure first solved by X-ray analysis in 1965 was that of the a-CyD complex with potassium acetate [11]. Structures of two other well-known CyDs, fi-CyD [12] and y-CyD [13, 14], were determined in 1976 and 1980, respectively. An up-to-date list of crystal structures determined by X-ray and/or neutron diffraction is collected in the Cambridge Crystallographic Database (http //www.ccdc.cam.ac.uk/). 

Definitive proof of the structure of porphine in the solid state awaits a variable-temperature crystallographic (X-ray or neutron diffraction) study the analysis of the anisotropic displacement factors (ADP) should disclose any rotational motion or its absence as well as determine the positions of the inner hydrogens. A search in the September 1998 version of the Cambridge Structural Database [CSD (91MI187)] showed that the only structures of porphine (codename PORPIN) were obtained in 1965 and 1972. 

Our approach to this chapter is best described as experimental rather than mathematical. There are many excellent formal texts, some of which will be cited. Here, we wish to summarize the fundamental purpose of each technique, to explore its possible applications and limitations, and to illustrate (or provide references to) its use in systematic studies of molecular structure. Most of the examples have been drawn from the Cambridge Structural Database [2], using the methods of search and retrieval detailed in the preceding chapter. We preface the statistical content with two more general chemical sections in the first we discuss the selection of geometric parameters that are most appropriate for certain types of analysis, whilst in the second we discuss the possible sources of variation in crystallographic structural data. 

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