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SUMMARY:Supramolecular Architectures for Artificial Photosynthesis - Profe
 ssor Marcella Bonchio (University of Padova and ITM-CNR\, Department of Ch
 emical Sciences)
DTSTART:20190123T154500Z
DTEND:20190123T164500Z
UID:TALK115699@talks.cam.ac.uk
CONTACT:Lingtao Kong
DESCRIPTION:All of Earth's oxygen is the result of water oxidation perform
 ed by photosynthetic organisms using solar light as the only energy source
 . The O2 necessary for our aerobic life is produced by the photocatalytic 
 cleavage of the extremely stable H-O-H bonds. Making oxygen is exceptional
 ly difficult and lethal for any biological factory\, which calls out a con
 tinuous self-repair cycle during oxygenic photosynthesis. Indeed\, and des
 pite the vast bio-diversity footprint\, just one specialized protein compl
 ex is used by Nature as the H2O-photolyzer: photosystem II (PSII). Man-mad
 e systems are still far from replicating the complexity of PSII. High reso
 lution imaging of the PSII “core” complex shows the ideal co-localizat
 ion of multi-chromophore Light Harvesting antennas with the functional Rea
 ction Center (LH-RC). Our results overcome the classical “photo-dyad” 
 model\, based on a donor-acceptor binary combination. Here we report the s
 elf-assembly of multi-perylenebisimide chromophores (PBI) shaped to functi
 on by interaction with a polyoxometalate water oxidation catalyst (Ru4POM)
 . \nThe resulting [PBI]5Ru4POM complex is identified as the minimal photos
 ynthetic unit\, formed both in solution and on photoelectrodes\, showing a
 : (i) a red-shifted\, light harvesting efficiency (LHE>40%)\, (ii) favorab
 le exciton accumulation and negligible excimeric loss\; (iii) a robust amp
 hiphilic structure\; (iv) dynamic aggregation into large 2D-paracrystallin
 e domains. Our results include the X-ray diffraction analysis of a dense\,
  quasi-hexagonal packing of the functional motif\, showing a striking anal
 ogy with the coexistence of fluid-to-crystalline phases in the native phot
 osynthetic membrane. Photoexcitation of the PBI-antenna triggers one of th
 e highest driving force for photo-induced electron transfer applied so far
 . The modularity of the building blocks\, the simplicity of the non-covale
 nt chemistry and the biomimetic appeal of the supramolecular approach\, of
 fer a unique opportunity for innovation in Artificial Photosynthesis.\n\n1
 )	Scheuring\, S. & Sturgis\, J. N. Chromatic Adaptation of Photosynthetic 
 Membranes. Science 309\, 484–487 (2005).\n2)	Sartorel\, A.\, Carraro\, M
 .\, Toma\, F. M.\, Prato\, M. & Bonchio\, M. Shaping the beating heart of 
 artificial photosynthesis: oxygenic metal oxide nano-clusters. Energy Envi
 ron. Sci. 5\, 5592 (2012).\n3)	Sartorel\, A. et al. Water Oxidation at a T
 etraruthenate Core Stabilized by Polyoxometalate Ligands: Experimental and
  Computational Evidence To Trace the Competent Intermediates. J. Am. Chem.
  Soc. 131\, 16051–16053 (2009).\n4)	Piccinin\, S.\; Sartorel\, A.\; Aqui
 lanti\, G.\; Goldoni\, A.\; Bonchio\, M.\; Fabris\, S. Water oxidation sur
 face mechanisms replicated by a totally inorganic tetraruthenium-oxo molec
 ular complex. Proc. Natl. Acad. Sci. 110\, 4917–4922 (2013)\n5)	Toma\, F
 . M. Prato\, M. & Bonchio\, M. et al. Efficient water oxidation at carbon 
 nanotube–polyoxometalate electrocatalytic interfaces. Nat. Chem. 2\, 826
 –831 (2010).\n\n
LOCATION:Wolfson Lecture Theatre\, Department of Chemistry
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