We have developed a new class of lanthanide nano-clusters that self-assemble using flexible Schiff base ligands. Cd-Ln and Ni-Ln clusters, [Ln8Cd24(L(1))12(OAc)39Cl7(OH)2] (Ln = Nd, Eu), [Eu8Cd24(L(1))12(OAc)44], [Ln8Cd24(L(2))12(OAc)44] (Ln = Nd, Yb, Sm) and [Nd2Ni4(L(3))2(acac)6(NO3)2(OH)2], were constructed using different types of flexible Schiff base ligands. These molecular nano-clusters exhibit anisotropic architectures that differ considerably depending upon the presence of Cd (nano-drum) or Ni (square-like nano-cluster). Structural characterization of the self-assembled particles has been undertaken using crystallography, transmission electron microscopy and small-angle X-ray scattering. Comparison of the metric dimensions of the nano-drums shows a consistency of size using these techniques, suggesting that these molecules may share similar structural features in both solid and solution states. Photophysical properties were studied by excitation of the ligand-centered absorption bands in the solid state and in solution, and using confocal microscopy of microspheres loaded with the compounds. The emissive properties of these compounds vary depending upon the combination of lanthanide and Cd or Ni present in these clusters. The results provide new insights into the construction of novel high-nuclearity nano-clusters and offer a promising foundation for the development of new functional nanomaterials.
We present as a case study the evolution of a series of participant-centered workshops designed to meet a need in the life sciences education community-the incorporation of best practices in the assessment of student learning. Initially, the ICABL (Inclusive Community for the Assessment of Biochemistry and Molecular Biology/BMB Learning) project arose from a grass-roots effort to develop material for a national exam in biochemistry and molecular biology. ICABL has since evolved into a community of practice in which participants themselves-through extensive peer review and reflection-become integral stakeholders in the workshops. To examine this evolution, this case study begins with a pilot workshop supported by seed funding and thoughtful programmatic assessment, the results of which informed evidence-based changes that, in turn, led to an improved experience for the community. Using participant response data, the case study also reveals critical features for successful workshops, including participant-centered activities and the value of frequent peer review of participants' products. Furthermore, we outline a train-the-trainer model for creating a self-renewing community by bringing new perspectives and voices into an existing core leadership team. This case study, then, offers a blueprint for building a thriving, evolving community of practice that not only serves the needs of individual scientist-educators as they seek to enhance student learning, but also provides a pathway for elevating members to positions of leadership.