Highly emissive dinuclear complexes [Au2{μ-(PPh2)2C2B9H10}(C6F5)(PR3)] with different gold fragments coordinated to an anionic diphosphine

Abstract

Reaction of the yellow-green emitters [Au{(PPh(2))(2)C(2)B(9)H(10)}(PR(3))] with [Au(C(6)F(5))(tht)] affords orange-red emissive gold complexes [Au(2){μ-(PPh(2))(2)C(2)B(9)H(10)}(C(6)F(5))(PR(3))] which contain different neutral (PR(3)) and anionic (C(6)F(5)) auxiliary ligands and an anionic diphosphine. The resulting complexes are among the few reported in which an ortho-carborane diphosphine acts in a bridging mode, and are unique in containing not a closo- (neutral), but a nido-carborane (anionic) cluster. DFT and TDDFT calculations led to the prediction of the origin of the two first singlet-triplet transitions, which is consistent with the experimental results. Although the blue emissive nido-diphosphine plays a key role in the transitions of the three-coordinate precursors and the final dinuclear complexes, it is the environment around the gold centre that controls the emission energy.

Influence of the group 11 metal on the emissive properties of complexes [M{(PR2)2C2B9H10}L]

“…Although it is not frequent, dual emission from two triplet states has been proposed in some gold complexes. 2,14 We propose for the one at higher energies an intraligand (IL) character, as commented for 8 and 11. The emissions at lower energy could have a more complicated…”

“…Thus, reactions with [Au(C 6 F 5 )(tht)] lead to dinuclear complexes [Au 2 {μ-(PPh 2 ) 2 C 2 B 9 H 10 }(C 6 F 5 )L] which display red or orange emissions. 2 Theoretical calculations indicate that the luminescence is mostly attributable to ligand (carborane) to gold-gold charge transfer (LMMCT) transitions. The final step in the analysis of the factors that may influence the emissive properties of these three-coordinated complexes is the modification of the metal.…”

Silver and gold

“…The emissions of the starting materials shift from yellow-green to orange-red because of the change of the environment at the gold centre. 86 The emission wavelength of dinuclear Ag(I) complexes can be tuned by the substituents of the anionic pincer-type bis(imidazolylidene) ligands. 87 The reaction of [{AuAg(C 6 X 5 ) 2 (NRCMe)} 2 ] n (X = F, Cl) with CuCl, pyrimidine and different nitriles leads to polymeric Au-Cu compounds with [Au(C 6 X 5 ) 2 ] units and the nitrile ligands coordinated to Cu-pyrimidine chains.…”

Trinuclear Gold–Carborane Cluster as a Host Structure

“…Ortho ‐carborane cages act as bridging ligands forming triangular cyclic structures [Au 3 Cage 3 ] 3– (Cage = 1,2‐ closo ‐C 2 B 10 H 10 , Figure ), with non‐bonded Au–Au distances of 3.78 Å . Moreover, gold clusters may exhibit luminescence, and the combination with carborane cages provides highly emissive systems …”