Zusammenfassung
Monomeric Ir(CO)(2)acac as it occurs in dilute solutions (<10(-3) M) absorbs only in the UV spectral region and shows a greenish luminescence (lambda(max) = 480 nm) which originates from the lowest-energy intraligand (acac) triplet. At higher concentrations a yellow coloration is observed which is attributed to the formation of oligomers. At 77 K these solutions turn blue owing to the presence of ...
Zusammenfassung
Monomeric Ir(CO)(2)acac as it occurs in dilute solutions (<10(-3) M) absorbs only in the UV spectral region and shows a greenish luminescence (lambda(max) = 480 nm) which originates from the lowest-energy intraligand (acac) triplet. At higher concentrations a yellow coloration is observed which is attributed to the formation of oligomers. At 77 K these solutions turn blue owing to the presence of oligomers which are characterized by strong metal-metal interactions. These blue oligomers display an intense red luminescence which consists of a fluorescence at lambda(max) = 662 nm and a phosphorescence at lambda(max) = 815 nm. (C) 2004 Elsevier B.V. All rights reserved.