Many challenges of chemoselectivity arise from the requirement to manipulate incompatible functional groups. Synthetic methods that do not rely on protecting groups are of strategic significance to chemical synthesis. Particularly valuable are molecules with reactive functionalities that are kinetically stabilized against inter- or intramolecular reactions with each other. We have developed a simple access to molecules that contain both ketone and N-H aziridine functionalities. These compounds were found to undergo highly selective reduction and carbonyl addition reactions, making them versatile precursors to complex amines.
In Cp* 2 Sr(bipy) the Cp* rings are completely staggered (see Fig. 1). Cg1 and Cg2 are the centroids of the rings defined by C1-C5 and C6-C10 respectively. The two pyridine rings in the bipyridine ligand are almost coplanar (the N-CC -N torsion angle is 2.2 (4)°). The least squares plane formed by the 12 atoms of the pyridine ring is tilted 10.7° relative to the plane formed by Sr,N1, and N2. This is larger than the equivalent angle in any other Cp* 2 M(bipy) in the Cambridge Structural Database (Allen, 2002). The closest is 5.1° in [Cp* 2 Yb(bipy)][Cp* 2 YbCl 2 ] (Schultz et al. 2002). The reason for this tilting is unclear as the Sr is d 0 and therefore electronic effects should be minor. At the same time it is unclear what steric reason could lead to this tilt. S2. Experimental Cp* 2 Sr(bipy) was prepared according to literature procedures (Burns and Andersen, 1987) S3. Refinement All non-hydrogen atoms were refined anisotropically. Hydrogen atoms were fixed based on the expected geometry of the carbon atoms to which they were attached. supporting information sup-2 Acta Cryst. (2008). E64, m1134 supporting information sup-9
Green design tools are emerging as a new response to the dilemmas that architects and designers face in preventing the toxic impacts of building construction. Environmental health advocates, scientists, and consulting firms are stepping in to provide designers with new tools—including science-based assessment methods, standards, databases, and software—intended to help structure and inform decision-making in sustainable design. We argue that green design tools play an important but largely uninvestigated role in giving designers new forms of influence while mediating how designers’ values are translated into actual design choices. Tool makers embed their own values and politics into the construction of the tools, which function as “black boxes”—their internal operations are understood as less important than their outputs for informing sustainable design. Using the green building movement as a case study, we consider three tools for selecting environmentally benign materials: the GreenScreen for Safer Chemicals, Pharos, and the Health Product Declaration. Examining controversies about the scientific validity of green design tools, we suggest that they are rooted in value conflicts and tensions in the politics of chemical knowledge. Transparent engagement with values and politics among tool developers and users could strengthen the legitimacy and credibility of green design tools.
People in contemporary industrial societies encounter countless novel materials that did not exist previously, many of which present risks to health and environment. In this article, we build on the concept of “materials sovereignty” as the right of people to use and be surrounded by environmentally benign, non-toxic, and renewing materials in their everyday lives. As a rights-based approach, materials sovereignty may help change the politics of governing materials. We suggest that social movements that explicitly base interventions into design on materials sovereignty may be better able to gain traction in changing industrial production. We consider the case of nanotechnology as a particularly challenging field for social movement intervention. We review several pathways that have been used by social movement organizations in attempts to influence the development of nanomaterials, but which have met with limited success. We more closely examine three participatory pathways through which social movements could intervene more directly into material design: participatory technology assessment, collaboration with industry, and co-design. We identify three key elements of materials sovereignty: participatory knowledge systems, which create multi-directional flows of knowledge and agency; the embedding of citizen voices into design processes; and building accountability systems. Of the pathways we examine here, co-design appears to be the most promising from a theoretical and ethical perspective, but there remain significant institutional and organizational challenges for bringing it into practice.
The substitution of hazardous substances with safer alternatives is being driven by policy pressures and business demands. As a result, scientific techniques for chemical alternatives assessment (CAA) have been established and communities of practice are emerging. Interest in safer chemical substitution is widely shared throughout a range of stakeholder groups across science, industry, public policy, and advocacy. Yet there is an unmet need for intentionally designed public information infrastructure to support the highly knowledge-intensive nature of CAA. We report here on the process of developing the Chemical Hazard Data Commons, an experimental project intended to support a diverse community of practitioners by providing publicly accessible chemical hazard data and tools for understanding it. In an arena where market forces and regulatory regimes have largely failed to generate the necessary knowledge, this project represents a novel application of a commons-based approach emphasizing building shared intellectual and technical capacity for CAA. The Data Commons-now a part of the related Pharos Project-includes an online portal providing simultaneous access to many different sources of information and enabling effective interactions with it. Foremost among these interactions are search and retrieval of hazard information about chemical substances, uniform display of the most relevant information, and the ability to automatically screen substances against consistent and transparent hazard-based criteria. We describe the motivation for the project and report on the principles and key considerations that guided its design as a participatory information infrastructure. We present our approach to organizing chemical information; the process of community engagement and planning; and how we constructed the system to provide functional tools. We discuss the outcomes of the project and highlight important challenges-such as fostering active participation and planning for long-term governance. With this article, we hope to inform future efforts for the collaborative development of knowledge resources for chemical alternatives assessment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.