A six-carbon 10π-electron aromatic system supported by group 3 metals

Tetraanionic Biphenyl Lanthanide Complexes as Single-Molecule Magnets

“…This suggests that, in the present arene-bridged system, the Ln-Cbiph interaction is stronger than Ln-CCOT, which is likely a consequence of the significant metalphenyl orbital overlap, as shown by DFT calculations on the diamagnetic counterpart, Y2-biph. 9 The slight difference in J between Gd2-biph and Gd2-biph-crown2 is consistent with a decreasing gadolinium-gadolinium distance. A difference in magnetic coupling (ferromagnetic vs. antiferromagnetic) of different lanthanide analogues, such as that observed in Dy2-biph-crown2, Er2-biph-crown2, and Gd2-biph-crown2, has been previously reported by Ishikawa et al 27 However, when considering all six complexes, it is interesting that ferromagnetic interactions are observed in complexes with closer Ln-Ln distances (4.14 Å or less) and antiferromagnetic interactions are observed in Dy2-biph, Gd2-biph-crown2 and Gd2-biph, each having Ln-Ln distances greater than 4.14 Å.…”

“…20 mL) layered with n-pentane (ca. 20 9 In a 20 mL scintillation vial, (NN TBS )DyI(THF)2 (0.4000 g, 0.457 mmol) and biphenyl (0.0352 g, 0.228 mmol) were dissolved in ca. 10 mL of THF.…”

P4 Activation by Lanthanum and Lutetium Naphthalene Complexes Supported by a Ferrocene Diamide Ligand

“…Colorless or white crystals of P4 were obtained at -35 °C and stored in a -35°C freezer prior to use. (NN fc )LaI(THF) [34] and (NN fc )LuI(THF)2 [35] were prepared following literature protocols. Nuclear magnetic resonance (NMR) spectra were recorded on Bruker AV300, Bruker DRX500, Bruker AV500 (work supported by the NSF grants CHE-1048804), or Bruker AV600 spectrometers at 25 °C in C6D6 or C7D8 unless otherwise specified.…”

Group 3 metal stilbene complexes: synthesis, reactivity, and electronic structure studies

“…The related diuranium inverse sandwich benzene or toluene complexes have been synthesized with various ancillary ligands and present a similar bonding character. [16][17][18][19][20][21] As mentioned, the  interaction is also present in M2K2-biph, 13 but to a lesser extent than in the corresponding uranium compounds. Since group 3 metal arene complexes supported by the ferrocene diamide ligand showed discrepancy in the binding mode of naphthalene and biphenyl, we became interested in synthesizing the corresponding (E)-stilbene complexes; the presence of multiple sites for reduction and binding, i.e., the C=C bond and the…”

“…8,9 Their classification with lanthanides rather than with transition metals is supported by the fact that, with few exceptions, 9 their complexes contain the metal in the +3 oxidation state, while transition metals display multiple oxidation states. Recently, our group reported the synthesis of group 3 metal naphthalene [10][11][12] and biphenyl complexes 13 supported by a ferrocene diamide ligand (NN TBS = 1,1′-fc(NSi This bonding dichotomy is in sharp contrast to diuranium inverse sandwich arene complexes of biphenyl, p-terphenyl, naphthalene, and (E)-stilbene supported by the same ketimide ligand (Chart 1b). 15 Despite the different nature of the arene, the resulting complexes shared analogous electronic structures, featuring  overlap between LUMOs of one phenyl ring and the two uranium centers.…”