This chapter describes the aspect of acid-base catalysis, the molecular mechanisms of the reactions, and the structure of the molecules. Most reactions catalyzed by acids and bases involve fairly complicated organic molecules, and closer analysis shows that in most catalyzed reactions in solution the...
A structure for nucleic acid has already been proposed by Pauling and Corey. They kindly made their manuscript available to us in advance of publication. Their model consists of three inter-twined chains, with the phosphates near the fibre axis, and the bases on the outside. In our opinion,...
Their model consists of three intertwined chains, with the phosphates near the fibre axis, and the bases on the outside. In our opinion, this structure is unsatisfactory for two reasons : (1) We believe that the material which gives the X-ray diagrams is the salt, not the free acid. ...
model the phosphates are on the outside and the bases on the inside, linked together by hydrogen bonds. This structure as described is rather ill-defined, and for this reason we shall not comment on it. We wish to put forward a radically different structure for the salt of deoxyribose nucl...
Commonly Used Bases in Organic Chemistry Common strong bases used in organic reactions are more varied in structure. It should be noted that: Strong bases have weak conjugate acids with high pKa values, usually > 12. Strong bases have a net negative charge, but not all negatively charged speci...
The distance of a phosphorus atom from the fibre axis is 10 A. As the phosphates are on the outside, cations have easy access to them. The structure is an open one, and its water content is rather high. At lower water contents we would expect the bases to tilt so that the structure...
structuretogether,especiallyasthenegativelycharged phosphatesneartheaxiswillrepeleachother.(2)Someofthevander Waalsdistancesappeartobetoosmall. Anotherthree-chainstructurehasalsobeensuggestedbyFraser(inthe press).Inhismodelthephosphatesareontheoutsideandthebaseson theinside,linkedtogetherbyhydrogenbonds.Thisstructure...
1翻译一篇生物英文论文Molecular Structure of Deoxypentose Nucleic Acids While the biological properties of deoxypentose nucleic acid suggest a molecular structure containing great complexity, X-ray diffraction studies described here show the basic molecular configuration has great simplicity. The purpose of ...
Crystals of -(-bromophenyl)-α--ribopyranosylamine 2,4-phenylboronate, CHONBBr, are monoclinic, with two molecules in a unit cell of the dimensions, =12.98, =10.80, =6.34, and β=99.4°, and with the space group of 2. The intensity data were collected by a photographic method and th...
Molecular structure of Nucleic acid沃森克里克威尔金斯1953年《Nature》737-740页