Cyclometallated complexes photochemistry

Cyclobutanones, Solution Phase Photochemistry of (Morton and Turro). Cyclometallated Complexes, Photochemistry and Luminescence of (Maestri, Balzani, Deuschel-Cornioley, and von Zelewsky). 

Rn(II) and Os(II) Complexes. We restrict ourselves again to the same class of compounds, as with Pd and Pt, that is, cyclometallated species with N- and C-donor atoms, that are parts of aromatic systems. Whereas cyclometallated complexes of this type have been reported for Ru(II), almost nothing is known about analogous Os(II) compounds. This is somewhat surprising, since third row transition metals in the other groups seem to be even more apt to form stable cyclometallated species compared to second row elements. There is probably still a lot of chemistry to be done in this field, with potentially very interesting applications to photochemistry. 

Thermal reactivity of those cyclometallated complexes which are interesting for photochemistry has not been widely and systematically studied so far. Two types of such reactions can be distinguished. 

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