Tris-bipyridine based dinuclear ruthenium(ii)-osmium(iii) complex dyads grafted onto TiO2 nanoparticles for mimicking the artificial photosynthetic Z-scheme.

Title Tris-bipyridine based dinuclear ruthenium(ii)-osmium(iii) complex dyads grafted onto TiO2 nanoparticles for mimicking the artificial photosynthetic Z-scheme.
Authors L. Favereau; A. Makhal; D. Provost; Y. Pellegrin; E. Blart; E. Göransson; L. Hammarström; F. Odobel
Journal Phys Chem Chem Phys
DOI 10.1039/c6cp06679h
Abstract

The Z-Scheme function within molecular systems has been rarely reported for solar energy conversion although it offers the possibility to achieve higher efficiency than single photon absorber photosystems due to the use of a wider range of visible light. In this study, we synthesized and investigated the electrochemical and spectroscopic properties of two new dyads based on ruthenium and osmium tris-bipyridine complexes covalently linked via a butane bridge to explore their ability to realize the Z-scheme function once immobilized on TiO2. These dyads can be grafted onto a nanocrystalline TiO2 film via the osmium complex bearing two dicarboxylic acid bipyridine ligands, while the ruthenium complex contains either two unsubstituted bipyridine ancillary ligands (RuH-Os) or two (4,4'-bis-trifluoromethyl-bipyridine) ancillary ligands (RuCF3-Os). Transient absorption spectroscopy studies of the Ru(ii)-Os(iii) dyads with femtosecond and nanosecond lasers were conducted both in solution and on TiO2. For both conditions, the photophysical studies revealed that the MLCT excited state of the ruthenium complex is strongly quenched and predominantly decays by energy transfer to the LMCT of the adjacent Os(iii) complex, in spite of the high driving force for electron transfer. This unexpected result, which is in sharp contrast to previously reported Ru(ii)-Os(iii) dyads, precluded us to achieve the expected Z-scheme function. However, the above results may be a guide for designing new artificial molecular systems reproducing the complex function of a Z-scheme with molecular systems grafted onto a TiO2 mesoporous film.

Citation L. Favereau; A. Makhal; D. Provost; Y. Pellegrin; E. Blart; E. Göransson; L. Hammarström; F. Odobel.Tris-bipyridine based dinuclear ruthenium(ii)-osmium(iii) complex dyads grafted onto TiO2 nanoparticles for mimicking the artificial photosynthetic Z-scheme.. Phys Chem Chem Phys. 2017;19(6):47784786. doi:10.1039/c6cp06679h

Related Elements

Osmium

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Titanium

See more Titanium products. Titanium (atomic symbol: Ti, atomic number: 22) is a Block D, Group 4, Period 4 element with an atomic weight of 47.867. The number of electrons in each of Titanium's shells is [2, 8, 10, 2] and its electron configuration is [Ar] 3d2 4s2. Titanium Bohr ModelThe titanium atom has a radius of 147 pm and a Van der Waals radius of 187 pm. Titanium was discovered by William Gregor in 1791 and first isolated by Jöns Jakob Berzelius in 1825. In its elemental form, titanium has a silvery grey-white metallic appearance. Titanium's properties are chemically and physically similar to zirconium, both of which have the same number of valence electrons and are in the same group in the periodic table. Elemental TitaniumTitanium has five naturally occurring isotopes: 46Ti through 50Ti, with 48Ti being the most abundant (73.8%). Titanium is found in igneous rocks and the sediments derived from them. It is named after the word Titanos, which is Greek for Titans.

Ruthenium

See more Ruthenium products. Ruthenium (atomic symbol: Ru, atomic number: 44) is a Block D, Group 8, Period 5 element with an atomic weight of 101.07. Ruthenium Bohr ModelThe number of electrons in each of ruthenium's shells is [2, 8, 18, 15, 1] and its electron configuration is [Kr] 4d7 5s1. The ruthenium atom has a radius of 134 pm and a Van der Waals radius of 207 pm. Ruthenium was discovered by Jędrzej Śniadecki in 1807. It was first recognized as a distinct element by Karl Ernst Claus in 1844. Elemental RutheniumIn its elemental form, ruthenium has a silvery white metallic appearance. Ruthenium is a rare transition metal belonging to the platinum group of metals. It is found in pentlandite, pyroxenite, and platinum group metal ores. The name Ruthenium originates from the Latin word "Ruthenia," meaning Russia.

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