TY - JOUR
T1 - Homoleptic diphosphacyclobutadiene complexes [M(η 4-P2C2R2)2]x- (M=Fe, Co; X=0, 1)
AU - Wolf, Robert
AU - Ehlers, Andreas W.
AU - Khusniyarov, Marat M.
AU - Hartl, Frantiåek
AU - Debruin, Bas
AU - Long, Gary J.
AU - Grandjean, Fernande
AU - Schappacher, Falko M.
AU - Pöttgen, Rainer
AU - Slootweg, J. Chris
AU - Lutz, Martin
AU - Spek, Anthony L.
AU - Lammertsma, Koop
PY - 2010/12/27
Y1 - 2010/12/27
N2 - The preparation and comprehensive characterization of a series of homoleptic sandwich complexes containing diphosphacyclobutadiene ligands are reported. Compounds [K([18]crown-6)(thf)2] [Fe(η4-P2C2tBu2) 2] (K1), [K([18]crown-6)(thf)2] [Co(η4-P2C2tBu2) 2] (K2), and [K([18]crown-6)(thf)2] [Co(η4-P2C2Ad2) 2] (K3, Ad=adamantyl) were obtained from reactions of [K([18]crown-6)(thf)2][M(η4-C 14H10)2] (M=Fe, Co) with tBuCï£P (1, 2), or with AdCï£P (3). Neutral sandwiches [M(η 4-P2C2tBu2)2] (4: M=Fe 5: M=Co) were obtained by oxidizing 1 and 2 with [Cp2Fe]PF6. Cyclic voltammetry and spectro-electrochemistry indicate that the two [M(η4-P2C2tBu2) 2]-/[M(η4-P2C 2tBu2)2] moieties can be reversibly interconverted by one electron oxidation and reduction, respectively. Complexes 1-5 were characterized by multinuclear NMR, EPR (1 and 5), UV/Vis, and Mössbauer spectroscopies (1 and 4), mass spectrometry (4 and 5), and microanalysis (1-3). The molecular structures of 1-5 were determined by using X-ray crystallography. Essentially D2d-symmetric structures were found for all five complexes, which show the two 1,3-diphosphacyclobutadiene rings in a staggered orientation. Density functional theory calculations revealed the importance of covalent metal-ligand π bonding in 1-5. Possible oxidation state assignments for the metal ions are discussed. Fancy a sandwich? Homoleptic sandwich anions that contain diphosphacyclobutadiene ligands result from the reaction of anthracene metalates [Fe(η4-C 14H10)2]- and [Co(η 4-C14H10)2]- with phosphaalkynes. Electrochemical and preparative investigations of [M(η4-P2C2tBu2) 2]- (M=Fe, Co) revealed that these anions are readily oxidized to neutral derivatives [M(η4-P 2C2tBu2)2]. The electronic structures of the new sandwich complexes have been elucidated by using spectroscopic techniques and density functional theory calculations.
AB - The preparation and comprehensive characterization of a series of homoleptic sandwich complexes containing diphosphacyclobutadiene ligands are reported. Compounds [K([18]crown-6)(thf)2] [Fe(η4-P2C2tBu2) 2] (K1), [K([18]crown-6)(thf)2] [Co(η4-P2C2tBu2) 2] (K2), and [K([18]crown-6)(thf)2] [Co(η4-P2C2Ad2) 2] (K3, Ad=adamantyl) were obtained from reactions of [K([18]crown-6)(thf)2][M(η4-C 14H10)2] (M=Fe, Co) with tBuCï£P (1, 2), or with AdCï£P (3). Neutral sandwiches [M(η 4-P2C2tBu2)2] (4: M=Fe 5: M=Co) were obtained by oxidizing 1 and 2 with [Cp2Fe]PF6. Cyclic voltammetry and spectro-electrochemistry indicate that the two [M(η4-P2C2tBu2) 2]-/[M(η4-P2C 2tBu2)2] moieties can be reversibly interconverted by one electron oxidation and reduction, respectively. Complexes 1-5 were characterized by multinuclear NMR, EPR (1 and 5), UV/Vis, and Mössbauer spectroscopies (1 and 4), mass spectrometry (4 and 5), and microanalysis (1-3). The molecular structures of 1-5 were determined by using X-ray crystallography. Essentially D2d-symmetric structures were found for all five complexes, which show the two 1,3-diphosphacyclobutadiene rings in a staggered orientation. Density functional theory calculations revealed the importance of covalent metal-ligand π bonding in 1-5. Possible oxidation state assignments for the metal ions are discussed. Fancy a sandwich? Homoleptic sandwich anions that contain diphosphacyclobutadiene ligands result from the reaction of anthracene metalates [Fe(η4-C 14H10)2]- and [Co(η 4-C14H10)2]- with phosphaalkynes. Electrochemical and preparative investigations of [M(η4-P2C2tBu2) 2]- (M=Fe, Co) revealed that these anions are readily oxidized to neutral derivatives [M(η4-P 2C2tBu2)2]. The electronic structures of the new sandwich complexes have been elucidated by using spectroscopic techniques and density functional theory calculations.
KW - cobalt
KW - iron
KW - metalates
KW - phosphorus
KW - sandwich complexes
UR - https://www.scopus.com/pages/publications/78651226719
U2 - 10.1002/chem.201001913
DO - 10.1002/chem.201001913
M3 - Article
AN - SCOPUS:78651226719
SN - 0947-6539
VL - 16
SP - 14322
EP - 14334
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 48
ER -