Investigation on Electronic and Thermoelectric Properties of (P, As, Sb) Doped ZrCoBi

Since the last decade, the half-Heusler (HH) compounds have taken an important place in the field of the condensed matter physics research. The multiplicity of substitutions of transition elements at the crystallographic sites X, Y and (III-V) elements at the Z sites, gives to the HH alloys a multitudes of remarkable properties. In the present study, we examined the structural, electronic and thermoelectric properties of ZrCoBi0.75Z0.25 (Z = P, As, Sb) using density functional theory (DFT). The computations have been done parallel to the full potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2k code. The thermoelectrically properties were predicted via the semi-classical Boltzmann transport theory, as performed in Boltztrap code. The obtained results for the band structure and densities of states confirm the semiconductor (SC) nature of the three compounds with an indirect band gap, which is around 1eV. The main thermoelectric parameters such as Seebeck coefficient, thermal conductivity, electrical conductivity and figure of merit were estimated for temperatures ranging from zero to 1200K. The positive values of Seebeck coefficient (S) confirm that the ZrCoBi0.75Z0.25 (x = 0 and 0.25) are a p-type SC. At the ambient temperature, ZrCoBi0.75P0.25 exhibit the large S value of 289 µV/K, which constitutes an improvement of 22% than the undoped ZrCoBi, and show also a reduction of 54% in thermal conductivity (κ/τ). The undoped ZrCoBi has the lowest ZT value at all temperatures and by substituting bismuth atom by one of the sp elements (P, As, Sb), a simultaneous improvement in κ/τ and S have led to maximum figure of merit (ZT) values of about 0.84 obtained at 1200 K for the three-doped compounds.

Bismuth atom tailoring of indium oxide surface frustrated Lewis pairs boosts heterogeneous CO2 photocatalytic hydrogenation

The surface frustrated Lewis pairs (SFLPs) on defect-laden metal oxides provide catalytic sites to activate H2 and CO2 molecules and enable efficient gas-phase CO2 photocatalysis. Lattice engineering of metal oxides provides a useful strategy to tailor the reactivity of SFLPs. Herein, a one-step solvothermal synthesis is developed that enables isomorphic replacement of Lewis acidic site In3+ ions in In2O3 by single-site Bi3+ ions, thereby enhancing the propensity to activate CO2 molecules. The so-formed BixIn2-xO3 materials prove to be three orders of magnitude more photoactive for the reverse water gas shift reaction than In2O3 itself, while also exhibiting notable photoactivity towards methanol production. The increased solar absorption efficiency and efficient charge-separation and transfer of BixIn2-xO3 also contribute to the improved photocatalytic performance. These traits exemplify the opportunities that exist for atom-scale engineering in heterogeneous CO2 photocatalysis, another step towards the vision of the solar CO2 refinery.

FeBiS2Cl – A new iron-containing member of the MPnQ2X family

The new sulfochloride FeBiS2Cl is obtained as a black powder following a mechanochemical synthesis procedure. The product crystallizes in the orthorhombic space group Cmcm (no. 63) with lattice parameters a = 3.82142(7), b = 12.2850(2) and c = 9.2911(2) Å. While the iron atom has an octahedral coordination environment, the bismuth atom is coordinated in the form of a bicapped trigonal prism. Both cation polyhedra form alternating layers, for iron built up of corner sharing octahedra along the c axis and edge sharing ones along the a axis. The bismuth polyhedra are connected through shared faces along the c axis and common edges along the a axis. Because of the distribution of sulfur and chlorine on a mixed anion site, the bismuth atoms occupy split positions. Experimental observations are supported by theoretical calculations.

Bismuth Atom Tailoring of Indium Oxide Surface Frustrated Lewis Pairs Boosts Heterogeneous CO2 Photocatalytic Hydrogenation

The surface frustrated Lewis pairs (SFLPs) on defect-laden metal oxides provide catalytic sites to activate H2 and CO2 molecules and enable efficient gas-phase CO2 photocatalysis. Lattice engineering of metal oxides provides a useful strategy to tailor the reactivity of SFLPs. Herein a one-step solvothermal synthesis is developed that enables isomorphic replacement of In3+ ions in UV-absorbing In2O3 by single-site Bi3+ ions to generate a new class of full-spectrum UV-Vis-NIR absorbing BixIn2-xO3 materials. Through compositional tuning, these materials prove to be three orders of magnitude more photoactive for the reverse water gas shift reaction (i.e., CO2 + H2 CO + H2O) than In2O3 itself, while also exhibiting notable photoactivity towards methanol production from carbon dioxide (i.e., CO2 + 3H2 CH3OH + H2O). The defective form of In2O3 containing oxygen vacancy sites can create SFLPs involving In3+ nearby the oxygen vacancy, which function as Lewis acidic sites, while lattice oxide O2- act as Lewis basic sites. In this study, it is discovered that the reactivity of these SFLPs can be further enhanced by single-site Bi3+ ion isomorphic substitution of Lewis acidic site In3+, thereby enhancing the propensity to activate CO2 molecules. In addition, the increased solar absorption efficiency and efficient charge separation and transfer of BixIn2-xO3 also contribute to the improved photocatalytic performance. These traits lead to enhanced binding and activation of CO2, exemplifying the opportunities that exist for atom-scale engineering in heterogeneous CO2 photocatalysis, another step towards the vision of the solar CO2 refinery.

Tris(Para-Tolyl)Bismuth Bis(Bromodifluoroacetate). Synthesis and Structure Features

The interaction of tri(para-tolyl)bismuth with tert-butyl hydroperoxide and bromodifluoroacetic acid in diethyl ether have synthesized tris(para-tolyl)bismuth bis(bromodifluoroacetate). The X-ray diffraction pattern for the crystal has been obtained at 293 K on an automatic diffractometer D8 Quest Bruker (MoKα-radiation, λ = 0.71073 Å, graphite monochromator), the results are [C25H21O4F4Br2Bi, M 830.22, the triclinic syngony, the symmetry group P–1; cell parameters: a = 10.292(8), b = 11.752(9), c = 12.693(9) Å, α = 89.42(2) degrees, β = 78.04(3) degrees, γ = 78.04(3) degrees; V = 1424.8(18) Å3; the crystal size is 0.73×0.57×0.41 mm; intervals of reflection indexes are –13 ≤ h ≤ 13, –15 ≤ k ≤ 15, –16 ≤ l ≤ 16; total reflections 45443; independent reflections 7096; Rint 0.1030; GOOF 1.049; R1 = 0.0739, wR2 = 0.1834; residual electron density 2.11/–2.78 e/Å3], the bismuth atom have a distorted trigonal-bipyramidal coordination. The OBiO axial angle is 172.2(3) degrees; the sum of the CBiC angles in the equatorial plane is 360.6. The Bi–O and Bi–C bond lengths are 2.275(8), 2.295(8) Å and 2.187(10)–2.212(13) Å. The Bi•••O=С distances are 3.127(10) and 3.159(10) Å, which is less than the sum of the van der Waals radii of bismuth and oxygen (3.59 Å). There are no intermolecular contacts H∙∙∙Hal in the crystal. Complete tables of coordinates of atoms, bond lengths and valence angles for the structure are deposited at the Cambridge Structural Data Bank (no. 1923097; [email protected]; http: //www.ccdc.cam.ac.uk).

Evaluation of dispersion type metal···π arene interaction in arylbismuth compounds – an experimental and theoretical study

The dispersion type Bi···π arene interaction is one of the important structural features in the assembly process of arylbismuth compounds. Several triarylbismuth compounds and polymorphs are discussed and compared based on the analysis of single crystal X-ray diffraction data and computational studies. First, the crystal structures of polymorphs of Ph3Bi (1) are described emphasizing on the description of London dispersion type bismuth···π arene interactions and other van der Waals interactions in the solid state and the effect of it on polymorphism. For comparison we have chosen the substituted arylbismuth compounds (C6H4-CH═CH2-4)3Bi (2), (C6H4-OMe-4)3Bi (3), (C6H3-t-Bu2-3,5)3Bi (4) and (C6H3-t-Bu2-3,5)2BiCl (5). The structural analyses revealed that only two of them show London dispersion type bismuth···π arene interactions. One of them is the styryl derivative 2, for which two polymorphs were isolated. Polymorph 2a crystallizes in the orthorhombic space group P212121, while polymorph 2b exhibits the monoclinic space group P21/c. The general structure of 2a is similar to the monoclinic C2/c modification of Ph3Bi (1a), which leads to the formation of zig-zag Bi–arenecentroid ribbons formed as a result of bismuth···π arene interactions and π···π intermolecular contacts. In the crystal structures of the polymorph 2b as well as for 4 bismuth···π arene interactions are not observed, but both compounds revealed C–HPh···π intermolecular contacts, as likewise observed in all of the three described polymorphs of Ph3Bi. For compound 3 intermolecular contacts as a result of coordination of the methoxy group to neighboring bismuth atoms are observed overruling Bi···π arene contacts. Compound 5 shows a combination of donor acceptor Bi···Cl and Bi···π arene interactions, resulting in an intermolecular pincer-type coordination at the bismuth atom. A detailed analysis of three polymorphs of Ph3Bi (1), which were chosen as model systems, at the DFT-D level of theory supported by DLPNO-CCSD(T) calculations reveals how van der Waals interactions between different structural features balance in order to stabilize molecular arrangements present in the crystal structure. Furthermore, the computational results allow to group this class of compounds into the range of heavy main group element compounds which have been characterized as dispersion energy donors in previous work.

COMPOUNDS OF BISMUTH AND ITS PORPHYRINE COMPLEXES: APPLICATION, STRUCTURE AND PROPERTIES

Bismuth and its compounds have been known since ancient times and now are widely used in practice in various fields. Bismuth use in medicine can be traced back to the Middle Ages, and its wide application is due to its very low toxicity - for most bismuth compounds it is less than for sodium chloride. Bismuth and its compounds, in particular salts, are used in medical practice in the treatment of diseases such as spirochetosis, gastric and duodenal ulcer, leishmaniasis and coronaviral infection, as well as in cancer therapy. In addition to solid preparations liquid peroral pharmaceutical forms have been developed for the treatment of diarrhea, colitis, ulcers etc. Bismuth preparations are used in stomatology for the treatment of inflammatory diseases of paradontium. The review considers the syntheses and properties of bismuth complexes with natural and synthetic porphyrins, which are used in medicine and other fields of science and technology. Considerable attention is paid to the structure features of bismuth porphyrins complexes, their dimeric structures, and the influence of various extra ligands. The counterion nature and structure make a substantial contribution in solving the problem of complexes stability. The central bismuth atom in these complexes extends far above the plane of the macrocycle due to the large ionic radius. Thus, the counterions action on the conformation, physicochemical properties and stability of metal porphyrins complexes is shown. A separate section is devoted to unique and interesting properties of bismuth porphyrins complexes, such as fluorescence and color variation of crystals.