Supramolecular schiff base coordination chemistry : blueprints for self-assembling metallocavitands and nanotubes

Heptametallic zinc(II) and cadmium(II) clusters have been isolated after reacting the metal-acetate salts with large diameter [3+3] Schiff base macrocycles. Two tetrazinc complexes have been characterized and identified as intermediates in the formation of the heptazinc complexes. The heptametallic complexes are, in fact, templated by the Schiff base macrocycles, a process that has been investigated with ¹H NMR spectroscopy and single-crystal X-ray diffraction. In the solid-state the heptametallic complexes have a bowl-shaped geometry, reminiscent of organic cavitands, leading to them being called metallocavitands. Solid-state investigation of the heptazinc and heptacadmium metallocavitands showed they organize into capsules with a cavity volume of 150 and 215 ų, respectively. Solution dimerization was also observed in aromatic solvents and N,N-dimethylformamide (DMF). The thermodynamics of dimerization have been quantified by van’t Hoff analyses of association constants measured with variabletemperature, variable-concentration ¹H NMR spectroscopy. Both metallocavitands exhibit entropy-driven dimerization in all solvents in which dimerization occurs. Unusual for dimerization of cavitands, this entropy-driven process can be attributed to the expulsion of solvent from the monomeric cavity upon dimerization. Inside the cavity of heptacadmium metallocavitands is a μ₃-OH ligand where the proton is located at the base of the cavity and is capable of hydrogen bonding with guest molecules. The μ₃-OH proton resonance is observable in low temperature 1H NMR spectra and exhibits two-bond J-coupling with three cadmium ions. Within capsules of the heptacadmium metallocavitands there are eight Lewis-acidic sites accessible to guest molecules, six unsaturated cadmium(II) centers and two μ₃-OH ligands. Solid-state analysis shows that two DMF molecules are encapsulated in the heptacadmium capsule where they each simultaneously exhibit a host-guest hydrogen-bond and a dative metalligand interaction. New methodology has been developed that facilitates synthesis of polydentate [2+2] Schiff base macrocycles with unsymmetrical salphen pockets. Also a [3+3] macrocycle with triptycenyl substituents has been synthesized to prohibit alkali-metal induced solution aggregation. The one-pot twelve component head-to-tail self-assembly of Pt₄ rings directed by chelating imine-pyridyl donors has been demonstrated. These supramolecules exhibit extensive columnar organization in both solution and the solid-state, a phenomenon that imparts liquid crystalline properties on the macrocycles.Science, Faculty ofChemistry, Department ofGraduat

Macromolecular Design Strategies for Preventing Active‐Material Crossover in Non‐Aqueous All‐Organic Redox‐Flow Batteries

Intermittent energy sources, including solar and wind, require scalable, low‐cost, multi‐hour energy storage solutions in order to be effectively incorporated into the grid. All‐Organic non‐aqueous redox‐flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox‐active species across the battery’s membrane. Here we show that active‐species crossover is arrested by scaling the membrane’s pore size to molecular dimensions and in turn increasing the size of the active material above the membrane’s pore‐size exclusion limit. When oligomeric redox‐active organics (RAOs) were paired with microporous polymer membranes, the rate of active‐material crossover was reduced more than 9000‐fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm−2 day−1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. This strategy was generalizable to both high and low‐potential RAOs in a variety of non‐aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next‐generation redox‐flow batteries.Besseres Sieben durch Chemie: Makromolekulare Chemie bietet einen allgemeinen Ansatz, um bei nur minimalem Verlust an Ionenleitfähigkeit den Durchtritt redoxaktiver organischer Moleküle durch Batteriemembranen zu blockieren. Dieses Resultat löst ein zentrales Problem für die Entwicklung von Redox‐Flow‐Batterien der nächsten Generation und bereitet den Weg für eine effiziente und preisgünstige Energiespeicherung.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135975/1/ange201610582-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135975/2/ange201610582_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135975/3/ange201610582.pd

Macromolecular Design Strategies for Preventing Active‐Material Crossover in Non‐Aqueous All‐Organic Redox‐Flow Batteries

Intermittent energy sources, including solar and wind, require scalable, low‐cost, multi‐hour energy storage solutions in order to be effectively incorporated into the grid. All‐Organic non‐aqueous redox‐flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox‐active species across the battery’s membrane. Here we show that active‐species crossover is arrested by scaling the membrane’s pore size to molecular dimensions and in turn increasing the size of the active material above the membrane’s pore‐size exclusion limit. When oligomeric redox‐active organics (RAOs) were paired with microporous polymer membranes, the rate of active‐material crossover was reduced more than 9000‐fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm−2 day−1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. This strategy was generalizable to both high and low‐potential RAOs in a variety of non‐aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next‐generation redox‐flow batteries.Better sieving through chemistry: Macromolecular chemistry provides a general approach for blocking redox‐active organic molecules from crossing through battery membranes at minimal cost to ionic conductivity. This advance solves a critical challenge facing next‐generation redox‐flow batteries, clearing the way toward efficient, low‐cost grid‐scale energy storage.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/136045/1/anie201610582-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136045/2/anie201610582_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136045/3/anie201610582.pd

Macromolecular Design Strategies for Preventing Active-Material Crossover in Non-Aqueous All-Organic Redox-Flow Batteries.

Intermittent energy sources, including solar and wind, require scalable, low-cost, multi-hour energy storage solutions in order to be effectively incorporated into the grid. All-Organic non-aqueous redox-flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox-active species across the battery's membrane. Here we show that active-species crossover is arrested by scaling the membrane's pore size to molecular dimensions and in turn increasing the size of the active material above the membrane's pore-size exclusion limit. When oligomeric redox-active organics (RAOs) were paired with microporous polymer membranes, the rate of active-material crossover was reduced more than 9000-fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm-2  day-1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. This strategy was generalizable to both high and low-potential RAOs in a variety of non-aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next-generation redox-flow batteries

Macromolecular Design Strategies for Preventing Active-Material Crossover in Non-Aqueous All-Organic Redox-Flow Batteries.

Intermittent energy sources, including solar and wind, require scalable, low-cost, multi-hour energy storage solutions in order to be effectively incorporated into the grid. All-Organic non-aqueous redox-flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox-active species across the battery's membrane. Here we show that active-species crossover is arrested by scaling the membrane's pore size to molecular dimensions and in turn increasing the size of the active material above the membrane's pore-size exclusion limit. When oligomeric redox-active organics (RAOs) were paired with microporous polymer membranes, the rate of active-material crossover was reduced more than 9000-fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm-2  day-1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. This strategy was generalizable to both high and low-potential RAOs in a variety of non-aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next-generation redox-flow batteries

Macromolecular Design Strategies for Preventing Active‐Material Crossover in Non‐Aqueous All‐Organic Redox‐Flow Batteries

Intermittent energy sources, including solar and wind, require scalable, low‐cost, multi‐hour energy storage solutions in order to be effectively incorporated into the grid. All‐Organic non‐aqueous redox‐flow batteries offer a solution, but suffer from rapid capacity fade and low Coulombic efficiency due to the high permeability of redox‐active species across the battery’s membrane. Here we show that active‐species crossover is arrested by scaling the membrane’s pore size to molecular dimensions and in turn increasing the size of the active material above the membrane’s pore‐size exclusion limit. When oligomeric redox‐active organics (RAOs) were paired with microporous polymer membranes, the rate of active‐material crossover was reduced more than 9000‐fold compared to traditional separators at minimal cost to ionic conductivity. This corresponds to an absolute rate of RAO crossover of less than 3 μmol cm−2 day−1 (for a 1.0 m concentration gradient), which exceeds performance targets recently set forth by the battery industry. This strategy was generalizable to both high and low‐potential RAOs in a variety of non‐aqueous electrolytes, highlighting the versatility of macromolecular design in implementing next‐generation redox‐flow batteries.Besseres Sieben durch Chemie: Makromolekulare Chemie bietet einen allgemeinen Ansatz, um bei nur minimalem Verlust an Ionenleitfähigkeit den Durchtritt redoxaktiver organischer Moleküle durch Batteriemembranen zu blockieren. Dieses Resultat löst ein zentrales Problem für die Entwicklung von Redox‐Flow‐Batterien der nächsten Generation und bereitet den Weg für eine effiziente und preisgünstige Energiespeicherung.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135975/1/ange201610582-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135975/2/ange201610582_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135975/3/ange201610582.pd

Property as Institutions for Resources: Lessons from and for IP

The idea of property in land as the paradigm case of property exercises despotic dominion over property thinking. From the perspective of evolving political economy, however, a land-centric model of property makes very little sense. Property institutions coordinate access to resources, and so it is reasonable to expect them to differ in ways that respond to the characteristics of those resources. The debate about whether intellectual property (IP) is property is instructive. IP scholars have pursued the property debate using a conceptual framework derived from common law real property doctrines and organized around the practical and theoretical problems associated with property rights in land, but the resources at the center of debates about the appropriate extent of IP-rightholder control could not be more different from land. Intellectual resources are routinely sliced and diced, aggregated and fractionated, used and reused, in ways that land is not and could not be. This might mean that IP is not property, as some have argued, or it might mean that we have outgrown the monolithic, land-centric model — that in the postindustrial era of wealth production, the cosmology of property can no longer place terra firma at the center. This Article develops an account of property as a set of resource-dependent legal institutions characterized by overlapping sets of family resemblances and then reconsiders the IP question. Property in intellectual goods resembles property in land in some respects, property in natural resources in other respects, property in corporations in others, and property in intangible financial instruments in still others, but also systematically diverges from each of those other forms of property. Legal institutions for IP must accommodate four important points of divergence: the different incentives of creators and intermediaries; the variety of ways in which intellectual goods are produced; the central importance of intermediation within IP ecologies; and the widespread use of licensing to delineate rights and obligations