Cage molecular conformation

Here the vector rj represents the centre of mass position, and D is usually averaged over several time origins to to improve statistics. Values for D can be resolved parallel and perpendicular to the director to give two components (D//, Dj ), and actual values are summarised for a range of studies in Table 3 of [45]. Most studies have found diffusion coefficients in the 10 m s range with the ratio D///Dj between 1.59 and 3.73 for calamitic liquid crystals. Yakovenko and co-workers have carried out a detailed study of the reorientational motion in the molecule PCH5 [101]. Their results show that conformational molecular flexibility plays an important role in the dynamics of the molecule. They also show that cage models can be used to fit the reorientational correlation functions of the molecule. 

Very different redox potentials were recently reported for the two stable conformers of a hexaaminecobalt(III) complex with a cage ligand (see Fig. 11.3). Two isomers with very different properties were isolated one is yellow (first d-d transition at 480 nm) with a potential of ° = 0.0 V, the other is blue (600 nm) with E = 0.84 V. The crystal structure of the yellow compound was solved (Fig. 11.3(a))[346], for the blue compound no diffracting crystals were isolated. That structure was solved by a combination of molecular mechanics, the simulation of the ligand field spectra (MM-AOM) and the redox potential (MM-Redox), see Fig. 11.3(b)13101. 

XIX is composed of two eleven-vertex e/oso-clusters linked by an inter-cage bridging dppp ligand, as shown in the illustration. This conclusion is supported by mass spectrometry, which shows the correct molecular ion, [M], centered at 1718.9 a.m.u., with an isotopic distribution which conforms to the calculated values for the proposed formulation of XIX. 

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