Phthalonitrile polymers have potential for high-temperature applications in polymer matrix composites as electronic encapsulation compounds. To investigate the effect of inclusion of an organosilicon moiety, a tetraphenylsilane-containing phthalonitrile monomer was synthesized in high yields. The monomer possessed a high melting point of 222–223°C, while no hydrolytic sensitivity was observed. Cured polymers exhibited glass transitions in the range of 290–325°C and coefficients of thermal expansion of 73–77 µm/(m °C). In thermogravimetric analysis (TGA), 5 wt% loss was observed at 482–497°C and 519–526°C, under air and nitrogen, respectively. Infrared (IR)-TGA of evolved gases revealed multiple degradations in both nitrogen and air. The material possessed good thermo-oxidative stability (TOS) when aged in air at 250°C. After aging for 5000 h, oxidative degradation was characterized using Fourier transform IR microscopy, energy dispersive spectroscopy, optical microscopy, and Knoop hardness testing. Four zones were identified in aged samples. The cleavage of Si-phenyl bonds and the formation of Si–O phases and carbonyl groups were observed.

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Three new coordination network molecule-based ferrimagnets of the general formula [V(acceptor)2]·x(solvent), where acceptor = 3,3′,5,5′-tetrafluorodicyanostilbene, 3,3′,4,4′,5,5′-hexafluorodicyanostilbene, or 2,2′,3,3′,5,5′,6,6′-octafluorodicyanostilbene and V = vanadium(II), have been prepared with ordering temperatures between 150 and 190 K. Including a previously reported compound, V[DCPFS]2·x(solvent), where DCPFS = dicyanoperfluorostilbene, the four represent a family of closely related compounds whose ordering temperatures can be used to infer the effects of fluorine substitution on the acceptors.

A triple-decker Tb2(Porphyrin)3 sandwich complex refines in both I4/m and I-4. In I4/m, the molecule has 4/m point symmetry, the refinement is stable, and the outer porphyrins are ordered, but significant disorder is modeled in the center porphyrin. Alternatively, in I-4, with molecular point symmetry -4, no disorder model is required, but heavy restraints/constraints are needed for the portion of the molecule that has 4/m point symmetry. This talk aims to stimulate discussion from the different schools of thought about which is the preferred space group choice for modeling the structure.

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