Previous literature reports have shown that single crystals of 1,2-bisIJ9-anthryl)acetylene (1), in which the molecule is essentially planar, can be fabricated as organic field effect transistors. We have identified a new conformational polymorph of 1 in which the two anthracene moieties are twisted out of plane by more than 60°. Occasionally, both the planar (1α) and twisted (1β) polymorphic forms crystallize out together representing a rare example of concomitant conformational polymorphism in a pure hydrocarbon. The two polymorphic forms also show distinctly different colours and morphologiesthe planar form (1α) grows as long orange-red needles whereas the twisted form (1β) appears as yellow blocks. Furthermore, a variety of electronic structure-based calculations show that the planar molecule forms the more stable polymorph (1α), despite the conformation being close to the maximum in conformational energy. This may be attributed to 1α being stabilized by greater intermolecular dispersion forces as the planar conformation allows a denser packing. The new polymorph (1β) is a long-lived metastable structure, because of the marked difference in crystal packing. Since the conformation in 1β is more stable in isolation, and probably in solution state, this discovery raises questions about the control of crystallization of anthracene-based functional materials and the assumptions about conformational polymoprhism commonly made in crystal structure prediction studies.
CrystEngCommThis journal is † Electronic supplementary information (ESI) available: The CIF files have been deposited with the Cambridge Crystallographic Data Centre. A supporting information file has also been supplied with further experimental and computational details. CCDC 1059941 1036772 For ESI and crystallographic data in CIF or other electronic format see
Youth fishing programs are an important gateway into continued fishing participation. With the current focus on R3 (recruitment, retention, and reactivation), it is important to understand the impacts fishing programs can have on their participants' knowledge, confidence, and interest in continuation. In this study, we conducted retrospective pre-post surveys of participants in a high school fishing program in Florida, USA, and compared results to a group of non-participating peers. We found significant increases in knowledge and confidence related to fishing skills among participants and significantly higher skills and confidence reported by participants as compared to non-participants. We also saw higher levels of self-identity as an angler as well as more desire to continue fishing on their own as compared to non-participants. The positive impacts of programs like this are important to the recruitment and retention of young anglers and continued evaluation of their effectiveness will lead to improved outreach programming.
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