Dipolarly unstable molecules

We will consider now the temperature dependence a(T) for high-symmetry molecules that have no proper dipole moment owing to symmetry properties, but owing to vibronic interactions possess an adiabatic potential with a finite number of minima of dipolar type at which the molecule has a dipole moment. Such molecules can be called dipolarly unstable molecules (DUM). The initial ground electronic term of these molecules can be both degenerate or nondegenerate. In the latter case in... 

In this section the properties of dipolarly unstable molecules (DUMs) in a viscous nonpolar medium in the presence of a electromagnetic field are considered. We consider especially the microwave spectrum of absorption. It is not related to the resonance transitions between rotational levels (nonresonance spectrum of Debye type). We assume that there is a weak solution of the DUM in a dense nonpolar medium in the presence of a variable electric field % t). The Hamiltonian of such a system has the form... 

Dipolarly Unstable Molecules with Three Minima... 

Nitrile oxides are usually prepared via halogenation and dehydrohalogenation of aldoximes [11] or via dehydration of primary nitro alkanes (Scheme 1) [12]. However, it is important to note that nitrile oxides are relatively unstable and are prone to dimerization or polymerization, especially upon heating. 1,3-Dipolar cycioaddition of a nitrile oxide with a suitable olefin generates an isoxazoline ring which is a versatile synthetic intermediate in that it provides easy access to y-amino alcohols, )5-hydroxy ketones, -hydroxy nitriles, unsaturated oximes, and a host of other multifunctional molecules (Scheme 1) [5a]. Particularly for the formation of )5-hydroxy ketones, nitrile oxide-olefin cycioaddition serve as an alternative to the Aldol reaction. 

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