Photochemical
studies of azido metal complexes of the type [M(NH,)sN,12', where M = Ir(III) and Rh(III) suggest the decomposition of the azido group via a coordinated nitrene intermediate [l-3]. The Ir(III) complex [4] and the corresponding Ru(III) complex [S] also react thermally with acid by a similar process. Since azido complexes (M-N,) are isoelectronic with isocyanato complexes (M-NO), it was decided to examine the photolysis of the latter in order to determine if a nitrene intermediate also forms. We wish to report here, however, that the photochemical reaction of [M(NH&NCO] (ClO,), for Ir (III) and Rh(II1) do not involve a nitrene path, and in neutral aqueous solutions photolysis of the Ru(II1) complex proceeds by ammonia aquation.
Experimental
Syntheses
The compounds MNW,NCOl(CW2, WOWWOI (CG)2, WW-GC11Cl2, WW%WM(~W~, WW-M,OHl(~W2 and Ru(NH~)~NCO~ were prepared by published methods [&8], and characterized by ultraviolet, visible and infrared spectra and by elemental analyses.
[Ru(NH&] Cl3 was obtained from Johnson-Matthey and Co. Ltd. (London), as a paleyellow powder and characterized as stated for the compounds which were prepared. All other chemicals and compounds used were analytical reagent grade.
Chromatographic Procedures
Chromatographic separation of aquopentaammine and hexaammine-ruthenium( III) ions was done using Bio-Rad AC 5OW-X2 (100-200 mesh) cation exchange resin in the H' form. The absorbed mixture