Luminescent metal complexes. Part 1. Tris-chelates of substituted 2,2′-bipyridyls with ruthenium (II) as dyes for luminescent solar collectors

Abstract

Ruthenium( 11) and osmium( 11) complexes of 2,2'bipyridyls (bipy) and 1,lO-phenanthrolines (phen) are identified as feasible dyes for use in luminescent solar collectors. Twenty-seven Ru"( bipy) 3 2 + complexes are prepared and the absorption and emission spectra of their solutions in EtOH-MeOH at room temperature are reported. Quantum efficiencies, which are sensitive to oxygen quenching, vary between 0.002 and 0.306 depending upon substituents. The effect of the medium on the spectral properties of selected compounds has also been investigated. Measured quantum yields of non-aqueous solutions are higher than those for aqueous solutions but lower than for doped plastic films.

Functionalisation of bolaamphiphiles with mononuclear bis(2,2′-bipyridyl)ruthenium(ii) complexes for application in self assembled monolayers

“…39,40 This behaviour is in agreement with related substituted complexes 20 and is due to the introduction of electron withdrawing groups which reduce the σ-donor strength of the bipy ligand, destabilising the metal based dπ-orbitals and hence the energy gap between the emitting 3 MLCT state and the ground state is reduced. 41 In addition, the energy of the 3 MC state is reduced, and hence non-radiative deactivation via this state is increased.…”

“…The λ max for each of the compounds varies only slightly from that of the parent complex [Ru(bipy) 3 ] 2+ in agreement with data obtained for complexes containing similar substituted 2,2'-bipyridines. 20 The emission spectra are typical of charge transfer emitters, and are similar in shape both at 298 K and 77 K to that of [Ru(bipy) 3 ]…”

“…For the most part this lack of interest is due to the relative ease of the synthesis of 4,4' derivatives in comparison with 5-and 5,5'-derivatives. While it may be possible to introduce substituents into the 4-position of a bipy via the Noxide, 20 bipy's substituted in the highly deactivated 5-position are generally prepared either via aryl coupling reactions 21 Figure 1). The method chosen to prepare 5-methyl-2,2'-bipyridyl is the widely used route to a large range of pyridine derivatives devised by Kröhnke and coworkers.…”

Photophysical and Redox Properties of Dinuclear Ru and Os Polypyridyl Complexes with Incorporated Photostable Spiropyran Bridge

“…17,18 Mononitration of commercially available 2,2′-bipyridine-N-oxide with NaNO 3 in concentrated H 2 SO 4 yielded 4-nitro-2,2′-bipyridine-N-oxide that was further converted into 4-bromo-2,2′-bipyridine in the presence of PBr 3 . [30][31][32] The 2,2′-bipyridine-4-boronic acid was obtained using a classical reaction with nBuLi and subsequent treatment with trimethylboran in diethyl ether at low temperature. 33 With ligand 1 in hand, for the first time, it proved possible to perform a double complexation reaction on a spiropyrantype ligand, which did not result in decomposition.…”

Static and Time-Resolved Spectroscopic Studies of Low-Symmetry Ru(II) Polypyridyl Complexes

“…The large body of knowledge concerning synthetic methodologies for preparing these complexes, coupled with a detailed understanding of their electronic structure, now enables predictable synthetic modulation of photophysical properties. 1,8,9 This potential for tunability has been most clearly demonstrated with bis-1,10-15 and tris-heteroleptic complexes, [16][17][18][19] in which two or three different ligands are incorporated into a single compound to create broadened MLCT bands. Asymmetric complexes have found use in photovoltaic systems, for example, wherein broadening of the MLCT absorption envelope holds promise for increased absorptive cross sections and thus a more efficient use of the solar spectrum for photoelectric conversion.…”