title: Cyclo-P₃ Complexes of Vanadium: Redox Properties and Origin of the ³¹P NMR Chemical Shift.
abstract: The synthesis and characterization of two high-valent vanadium-cyclo-P3 complexes, (nacnac)V(cyclo-P3)(Ntolyl2) (1) and (nacnac)V(cyclo-P3)(OAr) (2), and an inverted sandwich derivative, [(nacnac)V(Ntolyl2)]2(μ2-η(3):η(2)-cyclo-P3) (3), are presented. These novel complexes are prepared by activating white phosphorus (P4) with three-coordinate vanadium(II) precursors. Structural metrics, redox behavior, and DFT electronic structure analysis indicate that a [cyclo-P3](3-) ligand is bound to a V(V) center in monomeric species 1 and 2. A salient feature of these new cyclo-P3 complexes is their significantly downfield shifted (by ∼300 ppm) (31)P NMR resonances, which is highly unusual compared to related complexes such as (Ar[(i)Pr]N)3Mo(cyclo-P3) (4) and other cyclo-P3 complexes that display significantly upfield shifted resonances. This NMR spectroscopic signature was thus far thought to be a diagnostic property for the cyclo-P3 ligand related to its acute endocyclic angle. Using DFT calculations, we scrutinized and conceptualized the origin of the unusual chemical shifts seen in this new class of complexes. Our analysis provides an intuitive rational paradigm for understanding the experimental (31)P NMR spectroscopic signature by relating the nuclear magnetic shielding with the electronic structure of the molecule, especially with the characteristics of metal-cyclo-P3 bonding.
authors.affiliation: Department of Chemistry and the Molecular Structure Center, Indiana University , Bloomington, Indiana 47405, United States.|Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB) , Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Balazs
authors.initials: B
authors.lastname: Pinter
authors.affiliation: Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia Pennsylvania 19104, United States.
authors.forename: Kyle T
authors.initials: KT
authors.lastname: Smith
authors.affiliation: Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia Pennsylvania 19104, United States.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kamitani
authors.affiliation: Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich Alexander University Erlangen-Nürnberg (FAU) , Egerlandstr. 1, 91058 Erlangen, Germany.
authors.forename: Eva M
authors.initials: EM
authors.lastname: Zolnhofer
authors.affiliation: Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia Pennsylvania 19104, United States.
authors.forename: Ba L
authors.initials: BL
authors.lastname: Tran
authors.affiliation: Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia Pennsylvania 19104, United States.
authors.forename: Skye
authors.initials: S
authors.lastname: Fortier
authors.affiliation: Department of Chemistry and the Molecular Structure Center, Indiana University , Bloomington, Indiana 47405, United States.
authors.forename: Maren
authors.initials: M
authors.lastname: Pink
authors.affiliation: Department of Chemistry, Queen's University , Kingston, Ontario, Canada K7L 3N6.
authors.forename: Gang
authors.initials: G
authors.lastname: Wu
authors.affiliation: Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia Pennsylvania 19104, United States.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Manor
authors.affiliation: Department of Chemistry and Pharmacy, Inorganic Chemistry, Friedrich Alexander University Erlangen-Nürnberg (FAU) , Egerlandstr. 1, 91058 Erlangen, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Meyer
authors.affiliation: Department of Chemistry and the Molecular Structure Center, Indiana University , Bloomington, Indiana 47405, United States.|Department of Chemistry, Korea Advanced Institute of Science and Technology , 34141 Daejeon, Korea.
authors.forename: Mu-Hyun
authors.initials: MH
authors.lastname: Baik
authors.affiliation: Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia Pennsylvania 19104, United States.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Mindiola