Spin-pairing model

Spin-pairing model of dioxygen binding and its application to various transition metal systems as well as hemoglobin cooperativity. R. S. Drago and B. B. Corden, Acc. Chem. Res., 1980, 13, 353-360 (39). 

To determine orientation of an adsorbed molecule relative to the mineral surface, one would need to employ dipolar recoupling techniques to extract the distance constraints between the selected spin species of the molecule and of the surface. For polypeptide-HAp systems, 13C 31P REDOR has been carried out for uniformly 13C labeled molecules, where numerical simulations show that the effect of 13C dipole-dipole interaction is relatively minor.125 For a study of bone sample, o-phospho-L-serine was taken as the model compound for the setup of the 13C 31P REDOR experiments, where the data can be well analyzed by a l3C-3lP spin-pair model with the intemuclear distance equal to 2.7 A.126 Concerning the effect of 31P homonuclear dipolar interaction on the spin dynamics, Drobny and co-workers have carried out a detailed REDOR NMR study of polycrystalline diammonium hydrogen phosphate ((NH4)2F1P04).127,128 The results show that the 15N 31P REDOR data can... 

EXAMPLE 9.2 Using the spin-pairing model above, predict the sign of the two-bond coupling constant (27hh) n H-13C-H. 

Most recent authors have discussed the bonding in dioxygen complexes in terms of molecular orbital theory. Thus Drago in his spin-pairing model for 77 complexes of cobalt proposes a M.O. diagram arising fi om the interaction of one jtg orbital of dioxy-... 

Overlap (i) is that proposed by Drago in his spin-pairing model and overlap (iii) that proposed by Stomberg for the peroxychromates. On overlap grounds alone the if complex (overlap (iii)) will clearly be more stable, and, indeed, rf complexes are the... 

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