title: Bioinspired nonheme iron complexes derived from an extended series of N,N,O-ligated BAIP ligands.
abstract: A series of mononuclear Fe(II) triflate complexes based on the 3,3-bis(1-alkylimidazole-2-yl)propionate ester (BAIP) ligand scaffold are reported. In these complexes, the tripodal N,N,O-BAIP ester ligand is varied by (i) changing the ester moiety (i.e., n-Pr, tert-Bu esters, n-Pr amide), (ii) changing the methylimidazole moieties to methylbenzimidazole moieties, and (iii) changing the methylimidazole moieties to 1-ethyl-4-isopropylimidazole moieties. The general structure of the resulting complexes comprises two facially capping BAIP ligands around a coordinatively saturated octahedral Fe(II) center, with either a transoid or cisoid orientation of the N,N,O-donor manifold that depends on the combined steric and electronic demand of the ligands. In the case of the sterically most encumbered ligand, a four-coordinate all N-coordinate complex is formed as well, which cocrystallizes with the six-coordinate complex. In combination with the catalytic properties of the new complexes in the epoxidation/cis-dihydroxylation of cyclooctene with H2O2, in terms of turnover number and cis-diol formation, these studies provide a number of insights for further ligand design and catalyst development aimed at Fe-mediated cis-dihydroxylation.
authors.affiliation: Organic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
authors.forename: Marcel A H
authors.initials: MA
authors.lastname: Moelands
authors.forename: Sjoerd
authors.initials: S
authors.lastname: Nijsse
authors.forename: Emma
authors.initials: E
authors.lastname: Folkertsma
authors.forename: Bas
authors.initials: B
authors.lastname: de Bruin
authors.forename: Martin
authors.initials: M
authors.lastname: Lutz
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Spek
authors.forename: Robertus J M
authors.initials: RJ
authors.lastname: Klein Gebbink
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry; D002384:Catalysis; D034242:Cyclooctanes / Q000737:chemistry; D005296:Ferrous Compounds / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry; D008024:Ligands; D008958:Models, Molecular; D011422:Propionates / Q000737:chemistry*
chemical_list: D034242:Cyclooctanes; D005296:Ferrous Compounds; D007093:Imidazoles; D008024:Ligands; D011422:Propionates; D006861:Hydrogen Peroxide