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An undergraduate inorganic chemistry course laboratory experiment has been developed. It is based on linkage isomerization by two-dimensional (super.31)P nuclear magnetic resonance spectroscopy. The experiment is in two parts, in the first of which students prepare linkage isomers and in the second of which 1-D and 2-D (COSY) (super.31)P NMR spectra and recorded. Assignments are made for the isomers and hydrolyzed products.

The solid state 31P NMR of tertiary phosphine substituted alkyl- and acyltetracarbonylmanganese(I) complexes were examined at 121 MHz. All the spectra revealed an asymmetric sextet due to 1J(sub Mn-P) spin-spin coupling and second-order quadrupolar effects are not suppressed by MAS. The chemical shift tensors, 1J(sub Mn-P) coupling constant, effective dipolar coupling constant and quadrupolar coupling constants were determined from the solid-state 31P spectra.

Although experts disagree on how often Alzheimer's disease (AD) and multiple-infarct dementia (MID) are accurately diagnosed, there is agreement that the diagnoses are difficult and perfect accuracy is not yet attainable. While AD results from biochemical and structural changes within neurons, MID results from ischemic damage to many small areas of the brain where blood flow has been inadequate. For patients with MID, treatment of the risk factors associated with stroke may prevent further deterioration; the deterioration of AD is inexorable. To help distinguish between AD and MID, it would be helpful to be able to examine the biochemical workings of the brain directly. While this is clearly not practical, the NMR, or nuclear magnetic resonance spectroscope, may be of some service. The NMR examines the behavior of atomic nuclei in a magnetic field; for atoms present in large enough quantities, such as phosphorous, the NMR can distinguish properties of the magnetic ''neighborhood'' the phosphorus atom exists in, and can thus provide information about relative quantities of different chemical forms which include the element. This method was used to distinguish the ratio of phosphocreatine to inorganic phosphate and the ratio of phosphomonoesters to phosphodiesters in the brains of both Alzheimer's patients and patients with multiple-infarct dementia. The ratio of phosphocreatine to inorganic phosphate proved to be elevated in both the temporoparietal region and frontal region of the brain in patients with MID. When used as a differentiating characteristic, this ratio was able to correctly distinguish all 10 test cases of MID from 16 of 17 cases of probable Alzheimer's. Similarly, both phosphomonoesters and the ration of phosphomonoesters to phosphodiesters were elevated in the temporoparietal region of patients with Alzheimer's disease. These two metabolic parameters may prove to be valuable in distinguishing between these clinically similar but etiologically different dementing disorders. (Consumer Summary produced by Reliance Medical Information, Inc.)

Several criteria should determine which radioisotope is used to label nucleic acids; this labelling is a necessary step in many molecular biology research techniques including filter hybridization and DNA sequencing. Three radioisotopes are now available: phosphorus 32 (32P), sulphur 35 (35S) and the recently introduced phosphorus 33 (33P). Detection sensitivity and the desired degree of spatial resolution are the most important factors to consider in choosing which of these radioisotopes to use. Although 32P and 35S will continue to be standard, new uses for 33P will probably soon be developed.