title: Iron(II) template synthesis of benzannulated triphospha- and triarsamacrocycles.
abstract: Nine-membered 1,4,7-triphospha- and triarsamacrocycles with unsaturated benzo-backbones have been prepared using the [Cp(R)Fe](+) unit as a template. The cyclisation involves the attack of a coordinated phosphide (or arsenide) nucleophile at an activated, electrophilic ortho-fluorophenyl substituent on a neighbouring pnictide donor. The macrocycle assembly is of the 2 + 1 type where two new chelate rings are formed from appropriately derivatised bidentate and monodentate phosphines/arsines. Both [(η(5)-C(5)H(5))Fe](+) and [(η(5)-C(5)Me(5))Fe](+) may be employed for the cyclisation with higher yields generally being observed with the unsubstituted Cp. All new compounds have been characterised by spectroscopic and analytical methods including the single-crystal X-ray structure determination of [(η(5)-C(5)H(5))Fe(tribenzo-9aneP(3)-Ph,Ph(F)(2))](+), 3a, and [(η(5)-C(5)H(5))Fe(tribenzo-9aneAs(3)-Ph,Ph(F)(2))](+), 5, as the tetraphenylborate salts. The crystal structures are isomorphous and show the unique conformation of these new macrocycles with a 'cup shaped' cavity formed by the rigid benzo-backbones. The 9aneAs(3) derivative is the first example of a nine-membered triarsamacrocycle.
authors.affiliation: School of Chemistry, Cardiff University, Cardiff, UK CF10 3AT.
authors.forename: Thomas
authors.initials: T
authors.lastname: Albers
authors.forename: Julia
authors.initials: J
authors.lastname: Baker
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Coles
authors.forename: Peter G
authors.initials: PG
authors.lastname: Edwards
authors.forename: Benson
authors.initials: B
authors.lastname: Kariuki
authors.forename: Paul D
authors.initials: PD
authors.lastname: Newman
mesh_terms: D001554:Benzene / Q000737:chemistry; D060326:Chemistry Techniques, Synthetic / Q000379:methods*; D018360:Crystallography, X-Ray; D003500:Cyclization; D007501:Iron / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D010720:Phosphines / Q000737:chemistry
chemical_list: D047028:Macrocyclic Compounds; D010720:Phosphines; D007501:Iron; D001554:Benzene