Synthesis of Ruthenium(II) Complexes Bearing Macrocyclic [11]ane‑P2CNHC Ligands by a Template-Controlled Domino Reaction

Coordination of 1,2-dis­[bis­(o-fluorophenyl)­phosphino]­ethane (1) and a β-functionalized isocyanide (2-azidoethyl isocyanide (3) or 2-nitrophenyl isocyanide (6)) in a facial manner to the­{Ru­(indenyl)}+ template followed by reduction of the isocyanides yielded the NH,NH-NHC complex [5]­[ZnCl4]0.5 for isocyanide 3 and the 2-aminophenyl isocyanide complex [8]Cl for isocyanide 6, respectively. Deprotonation of the ring nitrogen atoms in [5]­[ZnCl4]0.5 gave, via an intramolecular nucleophilic substitution, complex [9]­[ZnCl4]0.5 bearing a facially coordinated [11]­ane-P2CNHC ligand. Attempts to remove the η5-indenyl ligand led to decomposition of [9]­[ZnCl4]0.5. Repetition of the template synthesis at the {Ru­(η5-2,4-dimethylpentadienyl)}+ template initially yielded complexes [13] and [15]­BF4, both bearing a 2-amine-substituted isocyanide. Cyclization of the isocyanides in [13] and [15]­BF4 to the NH,NH-NHCs was achieved by amine deprotonation with KOtBu. This led not only to the formation of the NHC ligand but also subsequently in a domino reaction to the formation of [11]­ane-P2CNHC macrocycles in complexes [16]­BF4 and [17]­BF4. The η5-pentadienyl ligand in [16]­BF4 and [17]­BF4 was substituted for a chlorido and two acetonitrile ligands to give the ruthenium­(II) complexes [18]­BF4 and [19]­BF4.