α-RuCl₃/Polymer Nanocomposites:  The First Group of Intercalative Nanocomposites with Transition Metal Halides

Abstract

Different types of polymers can be intercalated into R-RuCl 3 with different synthetic methodologies. Polyaniline/R-RuCl 3 nanocomposite was prepared by the in situ redox intercalative polymerization method, in which R-RuCl 3 was exposed to an aniline/acetonitrile solution in open air. Water-soluble polymers such as poly(ethylene oxide), poly(vinyl pyrrolidone), and polyethylenimine were intercalated by an encapsulative precipitation method using monolayer suspensions of R-RuCl 3 . A modification of this method led to insertion of polypyrrole. Monolayer suspensions of R-RuCl 3 can be prepared from Li x RuCl 3 (x ∼ 0.2). The latter is produced by the reaction of R-RuCl 3 with 0.2 equiv of LiBH 4 . The polymer insertion is topotactic and does not cause structural changes to the host. The metal chloride layers in these materials possess mixed valency. The reduction and polymer intercalation of R-RuCl 3 alters the intralayer and interlayer Ru 3+ (low spin d 5 ) magnetic coupling, so that interesting magnetic properties appear in the nanocomposites. In addition, the reduction brings in free hopping electrons to the RuCl 3 layers and the polymer intercalation builds up new electronic or ionic conducting channels in the galleries, so that the charge transport properties are changed dramatically. For example, Li x RuCl 3 shows an electrical conductivity 3 orders of magnitude higher than pristine R-RuCl 3 at room temperature and Li x (PEO) y RuCl 3 has an ion conductivity comparable with the best (lithium salt)-polymer electrolytes. For a comprehensive understanding of the structure of the representative nanocomposite Li x (PEO) y RuCl 3 , the arrangement of polymer chains inside the galleries was explored with analysis of its one-dimensional (00l) X-ray diffraction pattern. Calculated electron density maps along the stacking c-axis lead to a structural model that fills each gallery with two layers of polymer chains exhibiting a conformation found in type-II PEO-HgCl 2 . The most consistent PEO arrangement in the gallery generates oxygen-rich channels in the middle of the gallery in which the Li ions can reside. The new nanocomposites were characterized with thermogravimetric analysis, infrared spectroscopy, powder X-ray diffraction, magnetic measurements, as well as electrical and ionic conductivity and thermopower measurements.

Simulation insights on the structure of nanoscopically confined poly(ethylene oxide)

“…In most cases, an accurate calculation necessitates more than 12 00n peaks, but given the experimental difficulties of obtaining peaks of such high order (and given the very small intensities of peaks beyond the 006), even the most precise experimental approaches only use the first five to seven 00n reflections. 9,31 Even more often, no estimations were made for the PEO conformations; instead, crystalline helical conformations were assumed in the intercalated films, a postulation usually biased by the misleading coincidence of the thickness of a helical PEO arrangement and the thickness of the intercalated PEO films (both were ca. 0.8 nm).…”

“…2 Because these systems self-assemble in highly ordered intercalated structures, it is easy to prepare samples with macroscopic quantities of severely confined polymers so that conventional analytical techniques such as solid-state NMR, dielectric spectroscopy, and X-ray and neutron diffraction studies can be successfully applied. [2][3][4][5][6][7][8][9][10][11] Such experimental investigations combined with simulation studies [12][13][14][15][16][17] unveil a striking picture for the physics of polymers in severe confinements between solid surfaces.…”

Thin film processing of MoO3 based hybrid materials

“…24) On the other hand, the activation energy of (PPy) x RuCl 3 is 0.1 eV. 30) These comparisons imply that the MoO 3 host layers play a dominant role in determining transport properties of (PPy) x MoO 3 . Carrier electrons are transferred from the PPy layers to the MoO 3 layers in the (PPy) x MoO 3 .…”

SiO2@FeSO4 NANO COMPOSITE AS NANOCATALYST FOR THE GREEN SYNTHESIS 1,1-DIACETATES FROM ALDEHYDES UNDER SOLVENT-FREE CONDITIONS

“…Experimental work has generally shown that virtually all types and classes of nanocomposite materials lead to new and improved properties when compared to their macrocomposite counterparts. 2,3 In organic reaction protection of functional groups during synthesis compounds are essential. 4 One of the important functional groups is aldehydes, because of easy converted to other organic groups for examples, alcohol, 5 carboxylic acids, 6 aldoximes.…”