A dissipative system is a thermodynamically open system which is operated out-of thermodynamic equilibrium in an environment with which it exchanges energy and matter. which is characterized by the spontaneous appearance of symmetry breaking and the formation of complex, sometimes chaotic, structures where interacting particles exhibit long-range correlations. As stated in the BESAC report Challenges at the Frontiers of Matter and Energy, “Virtually everything interesting that happens in the universe is a result of departures from equilibrium”. While a number of elegant examples of nonequilibrium macroscopic and colloidal systems have been demonstrated, for this proposal we focus on dissipative chemical systems involving discrete bond making and breaking events or changes in molecular geometry. To be useful, the fueled chemistry must be coupled to some other functional behavior. A useful demonstration would be the transient assembly of supramolecular hosts: In principle, this could be used to create“catch and release” systems. We focused on tetramethylene glycol and pentamethylene glycol diacids TEG-Ac and PEG-Ac. The product is perfect. But the reaction speed of the TEG-Ac and PEG-Ac are influenced by the cations in the solution. The net yields of TEG-Cy fall in the order Li+ > Na+ > Cs+ > K+, the yields of the larger crown ether analogue PEG-Cy are less strongly affected by the presence of cations,but fall off gradually in the order Li+ > Na+ > K+ > Cs+. While accelerated hydrolysis of the macrocycles because of cation binding would shorten their lifetimes, it would not affect the total amount produced and thus not affect the yields.
Author: Meng Gu
Faculty Advisor: Michael Kennedy, Department of Chemistry & Biochemistry
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