Influence of the electronic characteristics of N-donor ligands in the excited state of heteronuclear gold(I)-copper(I) systems
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Universidad de La Rioja
info
ISSN: 0020-1669
Año de publicación: 2011
Volumen: 50
Número: 15
Páginas: 6910-6921
Tipo: Artículo
beta Ver similares en nube de resultadosOtras publicaciones en: Inorganic Chemistry
Resumen
By reaction of the heterometallic gold-silver complexes [{AuAg(C 6F5)2(N≡C-Me)}2]n or [{AuAg(C6Cl5)2(N≡C-Me)} 2]n and CuCl in the presence of pyrimidine and different nitrile ligands (acetonitrile, benzonitrile, and cinnamonitrile), the heteronuclear complexes {[Au(C6X5)2][Cu(L) (μ2-C4H4N2)]}n (X = F and L = N≡C-Me (1), L = N≡C-Ph (2) or N≡C-CH=CH-Ph (3); X = Cl and L = N≡C-Me (4), N≡C-Ph (5), N≡C-CH=CH-Ph (6)) have been prepared. The crystal structures of complexes {[Au(C6X 5)2][Cu(L)(μ2-C4H 4N2)]}n (X = F; L = N≡C-CH=CH-Ph (3), X = Cl; L = N≡C-Ph (5)) have been determined by X-ray diffraction studies. The crystal structures of both complexes consists of polymeric chains formed by the repetition of [Au(C6X5)2][Cu(L) (μ2-C4H4N2)] units through copper-pyrimidine bonds. Complexes 1, 2, 4, and 5 are brightly luminescent in the solid state at room temperature and at 77 K with lifetimes in the microseconds range. These compounds are also luminescent in solution, displaying different photophysical behaviors depending on the donor characteristics of the solvents used. The distortion in the excited state allows an associative attack by donor solvents quenching one of the emitting excited states. DFT optimizations of the ground (S0) and lowest triplet excited state (T1) display the structure distortion of the complexes upon electronic excitation. The molecular orbitals involved in the electronic transitions responsible for the phosphorescence in the case of the complexes 1, 2, 4, and 5 are related to metal (gold-copper) to ligand (pyrimidine) charge transfer transitions, while in the case of the nonluminescent complexes 3 and 6, the nonradiative electronic transition arises from metal (gold-copper) to ligand (cinnamonitrile) charge transfer transitions. © 2011 American Chemical Society.