Double triplet

The double triplet results from the unique phosphorus, split into a triplet by interaction with two equivalent phosphorus atoms (/(P-P) 25 Hz) then split into a doublet by rhodium (/(Rh-P) 145 Hz). 

For example, the double triplet (6 6.16) was obscured due to the poor signal-to-noise and the severe second order coupling at 100 MHz. Simulations (7,8) of the olefinic protons were critical to these assignments (Figure 3). 

Further evidence for the occurrence of the degenerate rearrangement in these compounds was obtained by NMR spectroscopy. The Z-form of 3-p-chlorophenyl-5-( -j -chlorophenyl- -[ N-amino])vinylisothiazole (171) showed in the non-proton-decoupled spectrum a double triplet for the amino nitrogen and a singlet for the heterocyclic ring nitrogen. It confirms that 171 is in fact an equilibrium mixture of 171 and 172 (Scheme IV.67). 

Isotropic g and 1H Hyperfine Values of Oxo-Cr(V)/35 Mixtures (m — Multiplicity t = Triplet dt = Double Triplet q = Quintet)... 

What is it about the S2 state that makes it play such a crucial role in governing the photochemical process The answer becomes readily apparent when we consider the simple VB representation for the doubly excited S2 state. The VB representation, [15] is that of a double-triplet which together... 

We have already seen a molecule with ailylic coupling. We discussed in some detail why cyclo-hexenone has a double triplet for H3. But it also has a less obvious double triplet for H2. The triplet coupling is less obvious because / is small (about 2 Hz) because it is 4/hh —ailylic coupling to the CH2 group at C4. Here is a diagram of the coupling, which you should compare with the earlier one for cyclohexenone. 

Figure 1. Exchange repulsion between two closed-shell molecules and the dependence of the activation barrier on the double-triplet excited state coupled to the singlet.

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