Synthesis of a TREN in Which the Aryl Substituents are Part of a 45 Atom Macrocycle

A substituted TREN has been prepared in which the aryl groups in (ArylNHCH2CH2)3N are substituted at the 3- and 5-positions with a total of six OCH2(CH2)nCHCH2 groups (n = 1, 2, 3). Molybdenum nitride complexes, [(ArylNCH2CH2)3N]­Mo­(N), have been isolated as adducts that contain B­(C6F5)3 bound to the nitride. Two of these [(ArylNCH2CH2)3N]­Mo­(NB­(C6F5)3) complexes (n = 1 and 3) were crystallographically characterized. After removal of the borane from [(ArylNCH2CH2)3N]­Mo­(NB­(C6F5)3) with PMe3, ring-closing olefin metathesis (RCM) was employed to join the aryl rings with OCH2(CH2)nCHCH­(CH2)nCH2O links (n = 1–3) between them. RCM worked best with a W­(O)­(CHCMe3)­(Me2Pyr)­(OHMT)­(PMe2Ph) catalyst (OHMT = hexamethylterphenoxide, Me2Pyr = 2,5-dimethylpyrrolide) and n = 3. The macrocyclic ligand was removed from the metal through hydrolysis and isolated in 70–75% yields relative to the borane adducts. Crystallographic characterization showed that the macrocyclic TREN ligand in which n = 3 contains three cis double bonds. Hydrogenation produced a TREN in which the three links are saturated, i.e., O­(CH2)10O.