The complexes [M2(p-XBP)3(N03)6] [M = Pr, Nd, Sm, Er; p-XBP = N,N'-xylene-l,4-diylbis(pyridin-2-one)] are shown by X-ray diffraction methods to contain the first example of an O-bonded triple helical bridge.

No abstract

No abstract

No abstract

In the polyamides 4.12, 10.6, 8.8 and 6.10 three fractions are present. The WAXD crystallinity is comparable to that of DSC and amounts to 40% in all samples. The rigid fraction obtained by solid state NMR is, however, close to 60%, pointing at 20% rigid amorphous material. A combination of the NMR, WAXD and SAXS results reveals that the latter fraction is situated inside the crystalline phase and not at the crystalline -'mobile amorphous' interface. Accordingly, one third of the crystalline layers with a thickness between 50 and 56 Å is not truly crystalline. From the width of the WAXD 100 reflections it can be deduced that crystalline grains exist with lateral dimensions of approximately 100 Å . Hence a picture emerges of alternating solid and liquid-like layers with the former consisting of crystalline grains separated by rigid amorphous matter.