Density functional theory methods were used to investigate self-assembled photoactive bioorganic system of interest for logically controlled artificial minimal cell. The cell system studied is based on cytosine and noncanonical oxo-guanine nucleobases and consisted of up to 366 atoms and are up to 2.5 nm in diameter. The electron correlation interactions responsible for the weak hydrogen and Van der Waals chemical bonds increase due to the addition of a polar water solvent molecules. The distances between the separated sensitizer, nucleobase, fatty acid precursor, and water molecules are comparable to Van der Waals and hydrogen bonding radii. As a result the associated electron correlation interactions compress the overall system resulting in an even smaller gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) electron energy levels and photoexcited electron tunneling occurs from the sensitizer (bis(4-diphenylamine-2-phenyl)-squarine and 1,4-bis(N,N-dimethylamino)naphthalene) to the precursor fatty acid, or to the cytosine molecules. Analysis of time dependent density functional theory method calculated absorption spectrum and images of electron transfer trajectories in the different excited states allow to separate quantum entangled photosynthetic transitions or destruction of 8-oxo-guanine::cytosine supramolecule. Two variable quantum OR logic gate consists of three subsystems: two photoactive sensitizer molecules and 8-oxo-guanine::cytosine supramolecule (or pFA) molecule, i.e., containing two different variable inputs and two different outputs.
Abstract:Density functional theory methods were used to investigate various self-assembled photoactive bioorganic systems of interest for artificial minimal cells. The cell systems studied are based on nucleotides or their compounds and consisted of up to 123 atoms (not including the associated water or methanol solvent shells) and are up to 2.5 nm in diameter. The electron correlation interactions responsible for the weak hydrogen and Van der Waals chemical bonds increase due to the addition of a polar solvent (water or methanol). The precursor fatty acid molecules of the system also play a critical role in the quantum mechanical interaction based self-assembly of the photosynthetic center and the functioning of the photosynthetic processes of the artificial minimal cells. The distances between the separated sensitizer, fatty acid precursor, and methanol molecules are comparable to Van der Waals and hydrogen bonding radii. As a result the associated electron correlation interactions compress the overall system, resulting in an even smaller gap between the highest occupied molecular orbital (HOMO), and lowest unoccupied molecular orbital (LUMO) electron energy levels and photoexcited electron tunnelling occurs from the sensitizer (either Ru(bpy) 2+ 3 or [Ru(bpy) 2 (4-Bu-4'-Me-2,2'-bpy)] 2+ + derivatives) to the precursor fatty acid molecules (notation used: Me = methyl; Bu = butyl; bpy = bipyridine). The shift of the absorption spectrum to the red for the artificial protocell photosynthetic centers might be considered as the measure of the complexity of these systems. 31.10.+z, 31.15.A-, 31.15.ae, 33.15.-e, 33.20.-
PACS (2008):
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