Organometallics 1983,2, 554-555
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strongly in the visible. For example, in acetonitrile ,A, for the lowest energy visible MLCT band in CH3CNoccurs at 445 nm for [Ru(bpy),(CO)H](PF,) (e 3170) and at 499 nm for [Os(phen),(CO)H](PFs) (t 5320). As can be seen from the data in Table I, the Os complexes represent rare examples of metal hydride complexes which luminesce in fluid solution at room temperature.', However, the complexes are weak emitters, 4, for [0~(bpy)~(Co)H](PF,) is in CH3CN at room temperature, and excited3.8 X state decay is dominated by nonradiative processes, 1/r0 N kn,. In this context the values of k,, in Table I are worthy of note. Especially striking are the values for the non-C0-containing hydrides, [Os(phen)(l,2(PhzP)&H4) (PPh3)H]+ and [Os(phen) (cis-Ph,PCH= CHPPh,)(PES)H]+. Compared to our earlier results based on the series (phen)O~L,~+, values for k, are
