Synthesis, structural characterization and magnetic property of nanocomposite materials: Intercalation compounds of FePS_3 with 1,10-phenanthroline or 2,2''''-bipyridine

Two new intercalation compounds Fe0.90PS3(phen)0.41 (1) (phen stands for 1,10-phenanthroline including a part of 1, 10-phenanthroline H ) and Fe0.83PS3(bipy)0.34 (2) (bipy stands for 2,2'-bipyridine H ) were synthesized by the reaction of the layered FePS, with 1,10-phenanthroline or 2,2'-bipyridine in the presence of anilinium chloride. They were characterized by elemental analyses, powder X-ray diffraction (XRD), infrared spectroscopy. The lattice spacing of the intercalate was expanded by 0.90 nm for Fe0.90PS3(phen)0.41 and 0.57 nm for Fe0.83PS3(bipy)0.34 withrespect to the pristine FePS3, indicating that the ring plane of the guests is perpendicular to the layer of the host. The UV-vis absorption spectra of the filtrate in preparation of the intercalates indicate that 1, 10-phenanthroline or 2,2'-bipyridine also acts as a complexing agent to remove intralamellar Fe2 ions into the solution during intercalation. The magnetic properties of 1 and 2 were studied.     

A New Inorganic-organic Nanocomposite, 4,4′-Bipyridine Intercalated into Lamellar FePS3

A new intercalation compound, Fe0.85PS3(4,4′-bipyH)0.30 (4,4′-bipy = 4,4′-bipyridine), is obtained by the intercalation of 4,4′-bipyridine·2HCl with lamellar FePS3, which is characterized by elemental analysis, powder X-ray diffraction, infrared spectroscopy. By comparison with the pure FePS3, the lattice spacing of Fe0.85PS3(4,4′-bipyH)0.30 is expanded by ～ 5.7(A), indicating that the ring plane of the guest is perpendicular to the layer of the host. The magnetic property of Fe0.85PS3(4,4′-bipyH)0.30 is studied with SQUID. It exhibits an antiferromagnetic phase transition with TN of about 70 K.     

Temperature dependence of the reflectance spectrum of (TMTSF)2ClO4

The near-infrared and visible reflectance spectrum was measured on (TMTSF)₂ClO₄ single crystal at various temperatures in the range of 30K–290K. The reflectance spectrum polarized parallel to the stacking axis was analyzed by Drude model, giving the results that the band width 4t is about 1 eV and m¹_p/m is about 1.3. The band parameters obtained here were almost the same as those of (TMTSF)₂PF₆ reported by Jacobsen et al.     

Singlet biradical character of phenalenyl-based Kekulé hydrocarbon with naphthoquinoid structure

[reaction: see text] A new Kekulé polycyclic hydrocarbon with a singlet biradical index of 50% was synthesized. The singlet biradical character was assessed with UV and 1H-NMR spectroscopy, cyclic voltammetry, SQUID magnetic susceptibility measurement, and quantum chemical calculations.     

Synthesis, Characterization, and Magnetic Properties of Intercalation Compound of 1,10-Phenanthroline with Layered MnPS3

A new intercalation compound Mn_0.84PS₃(phen)_0.64 (phen=1,10-phenanthroline) was synthesized in one step by direct reaction of host MnPS₃ with 1,10-phenanthroline, which was characterized by elemental analysis, X-ray powder diffraction, and infrared spectroscopy. As a result of intercalation, the lattice spacing of the intercalate expanded by 8.63 Å with respect to the pristine MnPS₃. For comparison, another new intercalation compound Mn_0.88PS₃[Mn(phen)₄]_0.12(H₂O) was also prepared in two steps by means of ion exchange. The studies of magnetic properties with SQUID-magnetometer indicated that the two intercalates, Mn_0.84PS₃(phen)_0.64 and Mn_0.88PS₃[Mn(phen)₄]_0.12 (H₂O), exhibit bulk spontaneous magnetization below 36 and 33 K, respectively.     

The Intercalation Reaction of 1,10-Phenanthroline with Layered Compound FePS3

The intercalation reaction of 1,10-phenanthroline with FePS₃ in ethanol and in the presence of anilinium chloride has been monitored in detail with the X-ray powder diffraction (XRD) method to study the reaction mechanism. It is revealed that during the intercalation period there are three phases: the 001 phase (corresponding to the perpendicular orientation of the 1,10-phenanthroline ring with the layer of the host FePS₃), the 001′ phase (standing for the parallel orientation of the 1,10-phenanthroline ring with the layer), and the 001″ phase (pristine FePS₃), but as the period of the reaction is prolonged, the 001′ and 001″ phases diminish gradually and finally disappear, and the 001 phase is intensified and a complete intercalate is obtained for Series A, in which excess 1,10-phenanthroline is used. However, for Series B in which the optimum amount of 1,10-phenanthroline is used, the 001 and 001″ phases diminish gradually, and another intercalate is obtained that exhibits the 001′ phase. Moreover, if the amount of phenanthroline used in the reaction is more than that in Series B but not in excess, another intercalate containing 001 and 001′ phases is obtained. In these intercalation reactions, the results of IR spectroscopy indicate that anilinium chloride serves only as the source of protons for 1,10-phenanthroline, but 1,10-phenanthroline acts as both the complexing agent of Fe²⁺ ions removed from FePS₃, confirmed by UV spectra of the filtrates, and the inserted guest, some of which exists in the form of protonated cation to maintain the charge balance of the intercalates. From the experimental evidence we find that the arranged orientation of 1,10-phenanthroline between the layers is controlled by the amount of guest used in the reaction, and a possible intercalation mechanism is proposed for the reaction.     

Infrared and Raman studies of the anion ordering transitions in paramagnetic organometallic radical cation salts [Cp2Mo(dmit)]X (X = PF6, SbF6)

Temperature dependence of infrared and Raman spectra of the two isostructural salts [Cp₂Mo(dmit)]PF₆ and [Cp₂Mo(dmit)]SbF₆ is studied. At room temperature the physical properties of both compounds are very similar but at lower temperatures they undergo phase transitions associated with anion ordering, which are surprisingly different. The phase transitions in [Cp₂Mo(dmit)]PF₆ salt at T₁ = 120 K and T₂ = 89 K have no important influence on infrared and Raman spectra, while the phase transition in [Cp₂Mo(dmit)]SbF₆ salt at T₁ = 175 K causes a splitting of Raman bands assigned to the CC stretching at about 1334 cm⁻¹ and the in-plane Mo(dmit) ring deformation at about 353 cm⁻¹, and also an infrared band at about 939 cm⁻¹ related to the C-S stretching. The splitting of vibrational bands demonstrates a clear distortion of [Cp₂Mo(dmit)]⁺ cations in the [Cp₂Mo(dmit)]SbF₆ salt. This molecular distortion is related to a lattice distortion providing thus a good argument for applicability of the compressible model of the anion ordering transition.     

Metallic and Mott Insulating Spin‐Frustrated Antiferromagnetic States in Ionic Fullerene Complexes with a Two‐Dimensional Hexagonal C60.− Packing Motif

(MDABCO⁺)(C₆₀^.?)(TPC) ( 1 ), in which MDABCO⁺ is N‐methyldiazabicyclooctanium, TPC is triptycene, and both have threefold symmetry, is a rare example of a fullerene‐based quasi‐2D metal and contains closely packed hexagonal fullerene layers with interfullerene center‐to‐center distances of 10.07 Å at 300 K. Evidence for the metallic nature of 1 was obtained by optical and microwave conductivity measurements on single crystals. The metal is characterized by a nontypical Drude response and relatively large optical mass (m*/m₀=6.7). The latter indicates a narrow‐band nature, which is consistent with the calculated bandwidth of 0.10–0.15 eV. The coexistence of metallic and antiferromagnetic nonmetallic 2D layers was observed in 1 above 200–230 K. It was assumed that the nonmetallic layers undergo a transition to the metallic state below 200 K due to ordering of the fullerene and cationic sublattices. New layered complex (MQ⁺)(C₆₀^.?)(TPC) ( 2 ) with a hexagonal arrangement of C₆₀^.? was obtained by increasing the interfullerene distance with the bulkier N‐methylquinuclidinium cations (MQ⁺) having threefold symmetry. The structure of 2 is characterized by increased interfullerene center‐to‐center distances in the layers (10.124, 10.155, and 10.177 Å at 250 K). Unit‐cell doubling parallel to the 2D layer (along the b axis) was observed at low temperatures. In contrast to metallic 1 , 2 exhibits a nonmetallic spin‐frustrated state with an antiferromagnetic interaction of spins (the Weiss temperature is ?27 K) and no magnetic ordering down to 1.9 K. It was supposed that the expanded interfullerene distances in the triangular arrangement decrease the bandwidth and suppress metallic conductivity in 2 , and thus a Mott–Hubbard insulating state with antiferromagnetically frustrated spins results.     

A New Inorganic-organic Nanocomposite,4,4''''-Bipyridine Intercalated into Lamellar FePS3

Interest in nanocomposite materials is increased due to their great significance in both fundamental and applied research fields in the past two decades 1. Intercalation of organic species into lamellar inorganic solids provides a useful approach to design and synthesize inorganic-organic nanocomposite materials with novel functional properties compared with the parent compounds 2. The transition metal phosphorous trisulfides, MPS3 (M stands for a metal in +2 oxidation state), are lamellar c…