NON‐Ligated N ‐Heterocyclic Tetrylenes

We report on the synthesis of N ‐heterocyclic tetrylenes ligated by the NON‐donor framework 4,5‐bis(2,6‐diisopropylphenyl‐amino)‐2,7‐di‐ tert ‐butyl‐9,9‐dimethylxanthene. The molecular structures of the germylene ( 3 ), stannylene ( 4 ) and plumbylene ( 5 ) where determined by X‐ray diffraction studies. Furthermore, we present quantum chemical studies on the σ‐donor and π‐acceptor properties of 3 – 5 . Additionally, we report on the reactivity of the tetrylenes towards the transition metal carbonyls [Rh(CO) 2 Cl] 2 , [W(CO) 6 ] and [Ni(CO) 4 ]. The isolated complexes ( 6 and 7 ) show the differing reactivity of NHTs compared to NHCs. Instead of just forming the anticipated complex [(NON)Sn−Rh(CO) 2 Cl], 4 inserts into the Rh−Cl bond to afford [(NON)Sn(Cl)Rh(CO)(C 6 H 6 )] ( 6 , additional CO/C 6 H 6 exchange) and [(NON)Sn(Cl)Rh 2 (CO) 4 Cl] ( 7 ). By avoiding halogenated transition metal precursors in order to prevent insertion reactions, germylene 3 shows “classical” coordination chemistry towards {Ni(CO) 3 } forming the complex [(NON)Ge−Ni(CO) 3 ] ( 8 ).