Template-Controlled Formation of an [11]ane-P2CNHC Macrocyclic Ligand at an Iron(II) Template

Complex [Fe(eta(5)-C5H5)(eta(6)-PhMe)]PF6 reacts with 1,2-bis[bis-(2-fluorophenyl)phosphanyl]benzene (2) in acetonitrile under irradiation for 6 h to give complex [Fe(eta(5)-C5H5)(2)(CH3CN)]PF6 ([3]PF6). Reaction of [3]PF6 with 1 equiv. of 2-azidoethyl isocyanide (4) yields complex [Fe(eta(5)-C5H5)(2)(4)]X ([5]X) (X = Br, PF6). Staudinger reaction with PPh3 at the azido function followed by hydrolysis of the iminophosphorane with HBr yields compound [6]X (X = Br-, PF6-) with an NH,NH-stabilized NHC ligand. The facially coordinated NH,NH-stabilized NHC and the fluorinated diphosphane ligands were linked by N,N'-deprotonation of the NHC and nucleophilic attack of the nitrogen atoms at two C-F bonds, which gave - after anion exchange with NH4PF6 - complex [1]PF6 bearing the macrocyclic [1]ane-P2CNHC ligand.