Databases Cambridge

Prior to our current investigations, we studied the structure of the dipeptide molecules that make up proteins. Based on the data supplied by the Cambridge database, the dipeptides were shown to adopt many types of arrangement mode in their crystalline state [9], Furthermore, it was shown that water, methanol,... 

The population of the Cambridge Database contains many biases that have to be considered when studying the statistical distribution of the space groups. In a recent study on the space group distribution, Wilson [137] has considered the question as to whether crystallographers exercise an inherent preference in the choice of the... 

Tel. 415-642-1259, fax 415-642-8369 Searching Cambridge database for molecules with specified bond vectors. 

R. Taylor,/. Appl. Crystallogr, 19, 90 (1986). CAMAL—A New Component of the Cambridge Database Software System. 

Phe-X-Phe (with and without ort/jo-substitution of the phenyl rings) demonstrates that even small structural variations of X e.g. in going from X = — O— to X = — NH—) drastically change the conformation maps [140]. The results of semiempirical calculations [140] are identical with the experimental data for corresponding structures as contained in the Cambridge database of crystal structures [141]. 

The program MIMUMBA starts from an arbitrary 3D structure and generates other conformations by changing individual torsion angles to values which correspond to different conformational preferences [968] the distribution profiles of allowed and preferred torsion angles are retrieved from corresponding partial structures in the Cambridge database of crystal structures [141]. 

Thus, we find that if the X-ray measurements are made at liquid nitrogen temperatures, the total errors are reduced by about half, say to about 0.003-0.005 A on average. Unfortunately, although X-ray crystallography is largely done at liquid nitrogen temperatures currently, most of the structural information in the Cambridge Database was determined in earlier times and at room temperature. 

A comparison of the Ln-0 distances of rare earth siloxides and alkoxides is complicated by a lack of structural information on alkoxides that have similar steric properties to triphenylsiloxides. However, according to a search in the Cambridge Database, the Ln-0 distances of aliphatic rare earth alkoxides appear to be somewhat smaller, consistent with the increased overall electron-releasing properties of alkoxides relative to siloxides. 

The Cambridge database contains a wealth of chemical information. Much of this is of immediate interest to organic chemists. " Just two brief... 

As with the Cambridge database, the Brookhaven organization supplies periodic updates and pertinent software. Information about subscribing to the service can be obtained from ... 

E. M. Ricketts, J. Bradshaw, M. Harm, F. Hayes, N. Tanna, and D. M. Ricketts, /. Chem. Inf. Comput. Set. 33, 905 (1993). Comparison of Conformations of Small Molecule Structures from the Protein Data Bank with Those Generated by CONCORD, COBRA, ChemDBS-3D, and CONVERTOR and Those Extracted from the Cambridge Database. 

Co-centroid distance of 31 Co-arene (benzene or toluene) complexes from Cambridge database (version 5.29, February 2008). 

Crystal structures. These have been extracted from the Cambridge Database, choosing only entries unaffected by disorder or other errors, and, in case of multiple determinations, selecting the most recent one, which is usually also the one with the lowest / -factor. Room-temperature determinations have been preferred because any simulation potential should preferably be applicable at room-T conditions low-temperature determinations have been selected when room-temperature ones were unacceptable for other reasons. When neutron diffraction data were available, these were selected for the positions of the hydrogen atoms. 

Fig. 11.9. The tag wavelengths (see text) of molecular crystals, from the colors by which they were described in the Cambridge Database (small subset), against the wavelength calcnlated from the Extended Hnckel A(HOMO-LUMO) gap. nm units.

Table 14.1 Problems encountered in the analysis of polymorphic crystal structures in the Cambridge Database. See text for discussion. Cell parameters in A and degrees...

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