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Title: Solid state structure of (pentamethylcyclopentadienyl)(2,4-dimethylpentadienyl)iron, Fe(C 5 Me 5 )(2,4-C 7 H 11 ), and its incorporation into silica aerogels

Authors:
; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1359780
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Polyhedron
Additional Journal Information:
Journal Volume: 116; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-04 09:14:23; Journal ID: ISSN 0277-5387
Publisher:
Elsevier
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Turpin, Gregory C., Ma, Zhiru, Arif, Atta M., Eyring, Edward M., Pugmire, Ronald J., and Ernst, Richard D. Solid state structure of (pentamethylcyclopentadienyl)(2,4-dimethylpentadienyl)iron, Fe(C 5 Me 5 )(2,4-C 7 H 11 ), and its incorporation into silica aerogels. United Kingdom: N. p., 2016. Web. doi:10.1016/j.poly.2016.03.010.
Turpin, Gregory C., Ma, Zhiru, Arif, Atta M., Eyring, Edward M., Pugmire, Ronald J., & Ernst, Richard D. Solid state structure of (pentamethylcyclopentadienyl)(2,4-dimethylpentadienyl)iron, Fe(C 5 Me 5 )(2,4-C 7 H 11 ), and its incorporation into silica aerogels. United Kingdom. doi:10.1016/j.poly.2016.03.010.
Turpin, Gregory C., Ma, Zhiru, Arif, Atta M., Eyring, Edward M., Pugmire, Ronald J., and Ernst, Richard D. 2016. "Solid state structure of (pentamethylcyclopentadienyl)(2,4-dimethylpentadienyl)iron, Fe(C 5 Me 5 )(2,4-C 7 H 11 ), and its incorporation into silica aerogels". United Kingdom. doi:10.1016/j.poly.2016.03.010.
@article{osti_1359780,
title = {Solid state structure of (pentamethylcyclopentadienyl)(2,4-dimethylpentadienyl)iron, Fe(C 5 Me 5 )(2,4-C 7 H 11 ), and its incorporation into silica aerogels},
author = {Turpin, Gregory C. and Ma, Zhiru and Arif, Atta M. and Eyring, Edward M. and Pugmire, Ronald J. and Ernst, Richard D.},
abstractNote = {},
doi = {10.1016/j.poly.2016.03.010},
journal = {Polyhedron},
number = C,
volume = 116,
place = {United Kingdom},
year = 2016,
month = 9
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.poly.2016.03.010

Citation Metrics:
Cited by: 1work
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  • The molecular structure of (eta/sup 5/-C/sub 5/Me/sub 5/)/sub 2/Fe/sub 2/(CO)/sub 4/ has been determined via x-ray diffraction. The dimer has a monoclinic unit cell of space group P2/sub 1//n with a = 8.372 (4) A, b = 9.864 (5) A, c = 13.872 (5) A, ..beta.. = 93.13 (1)/sup 0/, V = 1144 (1) A/sup 3/, d/sub calcd/ = 1.43 g/cm/sup 3/, d/sub obsd/ = 1.46 g/cm/sup 3/, and Z = 2. The molecule contains two terminal and two bridging carbonyl ligands with a normal Fe-Fe single bond separation of 2.560 (1) A. The most unusual finding in this studymore » is that, unlike the case for the unsubstituted analogue (eta/sup 5/-C/sub 5/H/sub 5/)/sub 2/Fe/sub 2/(CO)/sub 4/, no significant variations in the cyclopentadienyl ligand C-C bond lengths are observed. This result may bear directly on the catalytic activity, or lack of it, observed in certain permethylated-cyclopentadienyl complexes.« less
  • The base-free ytterbocenes (Me{sub 5}C{sub 5}){sub 2}Yb, (Me{sub 4}C{sub 5}H){sub 2}Yb, and [1,3-(Me{sub 3}C){sub 2}C{sub 5}H{sub 3}]{sub 2}Yb have been prepared from their diethyl ether adducts, synthesized by reaction of YbI{sub 2} and the sodium salt of the substituted cyclopentadiene anion in diethyl ether. The structures of the base-free molecules have been determined by X-ray crystallography. The molecule (Me{sub 5}C{sub 5}){sub 2}Yb has been found to crystallize in two different morphologies; the complex also forms inclusion complexes with toluene, ortho-carborane, meta-carborane, and 1,2-dimethyl-ortho-carborane. The ytterbocene molecule in all of the derivatives examined is bent in the solid state with centroid-metal-centroidmore » angles ranging from 132{degree} to 147{degree}. A detailed examination of the structures and comparison with the reported structures of (Me{sub 5}C{sub 5}){sub 2}Eu, (Me{sub 5}C{sub 5}){sub 2}Sm, [1,3-(Me{sub 3}Si){sub 2}C{sub 5}H{sub 3}]{sub 2}Yb, and [1,3-(Me{sub 3}Si){sub 2}C{sub 5}H{sub 3}]{sub 2}Eu reveal that bending is the general structural preference. Close inter- or intramolecular contacts are observed in every case between the ytterbium atom and one or more carbon atoms other than those of the two cyclopentadienide rings of that ytterbocene fragment. The packing geometry is dictated by the substituents on the cyclopentadienide rings, the molecules arranging so as to minimize crowding in the solid state. The net result is a coordination polymer, dimer, or monomer, depending on the ring substituents.« less
  • Silica aerogels represent a new class of open-pore materials with pore dimensions on a scale of tens of nanometers, and are thus classified as mesoporous materials. In this work, we show that the combination of NMR spectroscopy and chemical-shift selective magnetic resonance imaging (MRI) can resolve some of the important aspects of the structure of silica aerogels. The use of xenon as a gaseous probe in combination with spatially resolved NMR techniques is demonstrated to be a powerful, new approach for characterizing the average pore structure and steady-state spatial distributions of xenon atoms in different physicochemical environments. Furthermore, dynamic NMRmore » magnetization transfer experiments and pulsed-field gradient (PFG) measurements have been used to characterize exchange processes and diffusive motion of xenon in samples at equilibrium. In particular, this new NMR approach offers unique information and insights into the nanoscopic pore structure and microscopic morphology of aerogels and the dynamical behavior of occluded adsorbates. MRI provides spatially resolved information on the nature of the flaw regions found in these materials. Pseudo-first-order rate constants for magnetization transfer among the bulk and occluded xenon phases indicate xenon-exchange rate constants on the order of 1 s-1 for specimens having volumes of 0.03 cm3. PFG diffusion measurements show evidence of anisotropic diffusion for xenon occluded within aerogels, with nominal self-diffusivity coefficients on the order of D= 10-3cm2/s.« less
  • Silica-modified pseudoboehmite aerogels (0, 10, 20 at% of Si) were prepared by sol–gel method followed by supercritical drying. The phase transformations, changes in structure and morphology upon calcination were thoroughly investigated by advanced X-Ray diffraction (XRD) techniques and high-resolution transmission electron microscopy (HRTEM). Obtained pseudoboehmite samples had specific nanostructure: ultrathin two-dimensional (2D) crystallites were loosely packed. The silica dopant drastically enhanced the crystallite anisotropy. Thus, the aerogel with Al:Si atomic ratio of 9:1 consisted of the pseudoboehmite nanosheets with thickness of one unit cell (average dimensions of 14.0×1.2×14.5 nm). The specific nanostructure caused remarkable features of experimental XRD patterns, includingmore » anisotropic peak broadening and appearance of forbidden reflection. Direct simulation of XRD patterns with using the Debye Scattering Equation allowed the size and morphology of pseudoboehmite crystallites to be determined. The silica addition strongly delayed formation of γ-alumina and further phase transformations upon calcinaton. Thermal stability of alumina was suggested to be affected by the particle morphology inherited from the pseudoboehmite precursor. - Graphical abstract: Pseudoboehmite samples had specific nanostructure: ultrathin two-dimensional (2D) crystallites were loosely packed. - Highlights: • Silica-doped boehmites were prepared by sol–gel method with supercritical drying. • Ultrathin two-dimensional crystallites of pseudoboehmite were obtained. • Changes in structure and morphology upon calcination were studied. • Simulation of XRD patterns was performed with use of the Debye Scattering Equation. • Thermal stability of alumina depended on morphology inherited from pseudoboehmite.« less