Bond angle effects

Bond angle effects. When the carbonyl-carbon is part of a ring system containing 3, 4 or 5 carbon atoms, the decrease in the bond angle of the two sp2-hybridised orbitals results in steric strain effects which cause the frequency of absorption of the carbonyl group to be shifted to higher values. 

In this work we will discuss the effects of embedding units and the cluster size, iising several related clusters. We have already calculated the Si-O-Si bond angle dependence of electronic structure of silicate clusters. The Si-O-Si bond angle effects, however, are being discussed in a more complete report, owing to the limited space. 

Optimized structure of sihcate tetrahedra in terms of bond lengths and bond angles Effect of isomorphous... 

Because of the stretching of the C=0 bond, carbonyl compounds generally give rise to a very strong infrared and a medium to strong Raman line between 1900 and 1550 cm". The position of the carbonyl band is influenced by inductive, mesom-eric. mass, and bond-angle effects [10]. 

The Nicholas and Pauson-Khand reactions, as well as the bond-angle effect, have been combined in a single synthetic scheme to make more efficient use of the cobalt. This has been done in a synthesis of epoxydictamine 7.90 (Scheme 7.24)." The Nicholas reaction was employed, in which a carbocation 7.87, generated from acetal 7.86, was trapped by an allylsilane nucleophile intramolecularly, to form the eight-membered ring... 

B. Bond-Angle Effects on P Chemical Shifts in Nontetracoordinated... 

Bond-angle changes and hence distortion fiom tetrahedral symmetry in tetracoordinated phosphorus compounds should affect the chemical-shift anisotropy as well. Dutasta et a/. (1981) experimentally have verified this bond-angle effect in a solid-state P-NMR study on a series of cyclic thioxophosphonates (1 -4). As shown in Table II, the shielding tensors are... 

In acyclic trivalent pho horus compounds, however, the bond-angle effect on P shifts does not follow the same pattern observed in tetracova-lent phosphorus compounds in fact, it is often opposite to the five-membered ring effect. Thus, from the data in Table III, Mann (1972) concluded... 

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