The complex [Ru(biq)(phen)(MeCN)2]2+ (biq = 2,2'-biquinoline, phen = 1,10'-phenanthroline, MeCN = acetonitrile) displays photoinduced ligand loss of the MeCN ligands when irradiated with visible light.    When monitoring the photolysis of the complex by 1H NMR and UV/Vis spectroscopy, it is apparent that one MeCN ligand is more photolabile than the other.  In fact this selective ligand loss can be enhanced by varying the wavelength of irradiation, in which one MeCN is ejected using low energy light while a switch to higher energy light ejects the other.  This selectivity is not observed in the symmetrical complexes [Ru(biq)2(MeCN)2]2+ and [Ru(phen)2(MeCN)2]2+.  The intermediate complex [Ru(biq)(phen)(MeCN)(pyridine)]2+ was isolated and characterized by X-ray crystallography.  Explanations will be given using time-dependent density functional theory (TD-DFT) calculations and other mixed bidentate ligand complexes will be discussed.  This phenomenon could be useful for time controlled drug release or as a synthetic tool for novel inorganic complexes.

Selective photoinduced ligand loss in asymmetric ruthenium(II) complexes

245th National Meeting (2013)

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