scholarly journals Pyrite-induced uv-photocatalytic abiotic nitrogen fixation: implications for early atmospheres and Life

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
E. Mateo-Marti ◽  
S. Galvez-Martinez ◽  
C. Gil-Lozano ◽  
María-Paz Zorzano
Keyword(s):  
Nitrogen Fixation ◽  
Triple Bond ◽  
Molecular Form ◽  
Iron Sulfate ◽  
Earth Atmosphere ◽  
Pyrite Surface ◽  
X Ray ◽  
Ultraviolet Irradiance ◽  
Emergence Of Life ◽  
Catalytic Effects

Abstract The molecular form of nitrogen, N2, is universally available but is biochemically inaccessible for life due to the strength of its triple bond. Prior to the emergence of life, there must have been an abiotic process that could fix nitrogen in a biochemically usable form. The UV photo-catalytic effects of minerals such as pyrite on nitrogen fixation have to date been overlooked. Here we show experimentally, using X-ray photoemission and infrared spectroscopies that, under a standard earth atmosphere containing nitrogen and water vapour at Earth or Martian pressures, nitrogen is fixed to pyrite as ammonium iron sulfate after merely two hours of exposure to 2,3 W/m 2 of ultraviolet irradiance in the 200–400 nm range. Our experiments show that this process exists also in the absence of UV, although about 50 times slower. The experiments also show that carbonates species are fixed on pyrite surface.

scholarly journals Pyrite-induced uv-photocatalytic abiotic nitrogen fixation: implications for early atmospheres and Life

2020 ◽  
Author(s):  
Eva Mateo-Marti ◽  
Santos Galvez-Martinez ◽  
Carolina Gil-Lozano ◽  
Maria-Paz Zorzano
Keyword(s):  
Nitrogen Fixation ◽  
Iron Sulfide ◽  
Molecular Form ◽  
Essential Element ◽  
Iron Sulfate ◽  
Earth Atmosphere ◽  
Pyrite Surface ◽  
Xps Spectra ◽  
Origin And Evolution ◽  
The Right

<p><strong>Pyrite-induced uv-photocatalytic abiotic nitrogen fixation: implications for early atmospheres and Life</strong></p> <p><strong> </strong></p> <ol> <li><strong> Mateo-Marti <sup>1</sup>, S. Galvez-Martinez<sup>1</sup>, C. Gil-Lozano<sup>1</sup> and María-Paz Zorzano <sup>1,2</sup></strong></li> </ol> <p> </p> <p><sup>1</sup>Centro de Astrobiología (CSIC-INTA), Torrejón de Ardoz, Madrid, Spain.</p> <p><sup>2</sup>Department of Computer Science, Electrical and Space Engineering, Luleå Universit of Technology, Luleå, Sweden.</p> <p><br /><br />  Nitrogen is an essential element for life, a prerequisite for the origin and evolution of life on Earth, or in any other potentially habitable planet. The molecular form of nitrogen, N<sub>2</sub>, is universally available but is biochemically inaccessible for life due to the strength of its triple bond. Prior to the emergence of life, there must have been an abiotic process that could fix nitrogen in a biochemically usable form. The UV photo-catalytic effects of minerals such as pyrite on nitrogen fixation have to date been overlooked. Here we show experimentally, using X-ray photoemission and infrared spectroscopies that, under a standard earth atmosphere containing nitrogen and water vapour at Earth or Martian pressures, nitrogen is fixed to pyrite as ammonium iron sulfate after merely two hours of exposure to 2,3 W/m2 of ultraviolet irradiance in the 200–400 nm range [1]. Our experiments show that this process exists also in the absence of UV, although about 50 times slower. The experiments also show that carbonates species are fixed on pyrite surface [Figure 1]. We conclude that UV photocatalysis on pyrite may have been a natural mechanism of prebiotic fixation of nitrogen into ammonium sulfates which is then easily released upon contact with liquid water. This property of pyrite may have been incorporated naturally in the prebiotic chemistry evolution, leading to the inclusion of pyrite nano-clusters as reaction centres to generate ammonia from nitrogen, and then from ammonia to generate ammonium sulfates salts in the presence of oxygen. This process has furthermore implication for the abiotic nitrogen fixation on other planetary environments, and it has critical implications for the habitability of planet and the origin of life.</p> <p> </p> <p><strong>Fig. 1</strong>    Picture of the Planetary Atmosphere and Surfaces Chamber and XPS spectra of the presence of ammonium sulfate on pyrite surface (on the left). Schematic representation of the processes that lead nitrogen fixation on pyrite surface (on the right), (i) by UV photo-catalysis under low pressure conditions (on the top) and, (ii) by the catalytic effect of iron oxide-iron sulfide tandem under visible light conditions and standard earth atmosphere (on the bottom).</p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p>[1]   E. Mateo-Marti, S. Galvez-Martinez, C. Gil-Lozano and M-P. Zorzano, Scientific Reports, <strong>9,</strong> 15311 (2019)</p>

Post-Synthetic Modification of UiO66 and its Application in Catalytic Reactions

2021 ◽  
Author(s):  
Mingshan Qin ◽  
Juan Gao ◽  
Dongwei Wei ◽  
Liuan Li ◽  
Cun Li ◽  
...  
Keyword(s):  
Ethyl Cyanoacetate ◽  
Knoevenagel Reaction ◽  
High Catalytic Activity ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Research Fields ◽  
Metal Organic ◽  
Catalytic Effects ◽  
Unique Surface

Abstract Because of their unique surface area and adjustable pore size, Metal-Organic Frameworks(MOFs) have been widely used in lots of research fields, such as catalysis, energy storage, sensing, separation. In this paper, as for the Knoevenagel reaction, UiO66 and other UiO series MOFs were synthesized and modified. UiO66 nanoparticles were prepared by one-pot method. 2-aminopyridine, 3-aminopyridine and 4-aminopyridine were used to prepare UiO66-2Py, UiO66-3Py and UiO66-4Py nanoparticles. UiO66-2Py, UiO66-3Py and UiO66-4Py nanoparticles were modified by activated arginine, lysine and glycine to synthesize UiO66-2Py-Arg, UiO66-3Py-Lys and UiO66-4Py-Gly. Finally, the obtained samples were used for the Knoevenagel catalytic condensation reactions of benzaldehyde and ethyl cyanoacetate. In this process, the prepared samples and their intermediates were characterized by infrared spectroscopy (IR) and X-ray diffraction(XRD), which showed that the modification of UiO66 was successful. UiO66-3Py-Lys and UiO66-4Py-Gly showed high catalytic activity in the supernatant determined by fluorescence spectrophotometer, and UiO66-4Py-Gly showed the best catalytic effects at the volume of 0.4mL benzaldehyde.

Darstellung, Reaktionen und spektroskopische Charakterisierung von [Os2X8]2-, X = Cl, Br, I, und Kristallstruktur von (PPN)2[Os2I8] · 2 CH2Cl2 / Preparation, Reactions and Spectroscopic Characterization of [Os2X8]2-, X = Cl, Br, I, and Crystal Structure of (PPN)2[Os2I8] · 2 CH2Cl2

1990 ◽  
Vol 45 (10) ◽  
pp. 1416-1424 ◽  
Author(s):  
W. Preetz ◽  
P. Hollmann ◽  
G. Thiele ◽  
H. Hillebrecht
Keyword(s):  
Crystal Structure ◽  
Structure Determination ◽  
Triple Bond ◽  
Room Temperature ◽  
Spectroscopic Characterization ◽  
Spectroscopic Constants ◽  
Monoclinic System ◽  
X Ray ◽  
Fine Structures

The triply bonded octahalogenodiosmate(III) anions [Os2X8]2-, previously known with X = Cl, Br, have now been extended to include the iodide with two staggered OsI4 units. This compound was prepared by treating [Os2Cl8]2- with Nal at room temperature in acetone solution. The structure determination by X-ray diffractometry on single crystals of (PPN)2[Os2I8] · 2 CH2Cl2, reveals crystallization in the monoclinic system, space group P21/c with Z = 4. The Os-Os triple bond is with 2.212(1) Å the longest within the three octahalogenodiosmates(III). The Raman spectra show ν(OsOs) at 285, [Os2Cl8]2-; at 287, [Os2Br8]2- and for the iodo compound at 270.1 cm-1 with up to three overtones. The spectroscopic constants are calculated to be ω1 = 270.9 cm-1; X11 = -0.50 cm-1. The 10 Κ UV-VIS spectra of solid [(n-C4H9)4N]2[Os2X8] exhibit δ-π* transitions with maxima at 723, 690 and 643 nm, superimposed by vibrational fine structures with long progressions of 195, 211 and 183 cm-1 for X = Cl, Br, I, respectively. Oxidation of [Os2X8]2-, X = Cl, Br with the corresponding halogen leads to the cleavage of the Os-Os bond, and the dekahalogenodiosmates(IV), [Os2X10]2-, are formed

Mechanochemical Reaction Between Sulfur and Ilmenite

1998 ◽  
Vol 51 (10) ◽  
pp. 947 ◽  
Author(s):  
Nicholas J. Welham
Keyword(s):  
Closed System ◽  
Thermal Processing ◽  
Ball Mill ◽  
Inert Gas ◽  
Iron Sulfate ◽  
Mechanochemical Reaction ◽  
X Ray Diffraction ◽  
Rutile Tio2 ◽  
X Ray ◽  
Closed Tube

An ilmenite (FeTiO3) concentrate has been milled with sulfur in a laboratory-scale ball mill for 100 h under a variety of conditions. X-Ray diffraction and thermal processing have shown that reaction occurs within the mill forming pyrite (FeS2) and rutile (TiO2). The reaction was of greatest extent in a mill run under 400 kPa of inert gas; some reaction occurred in a mill under 10-2 Pa, whereas little reaction was observed when either water or air was present. Annealing of the product powders showed that reaction to TiO2 and FeS2 could be achieved in a closed system after 1 h at 400C but with the evolution of SO2, whereas annealing at 800C also gave TiO2 and FeS2, but without formation of SO2 which was thought to have disproportionated to form iron sulfate(VI). Closed-tube annealing of unmilled sulfur and milled ilmenite showed the same reactions as milled powders but of much greater extent.

The crystal and molecular structure of 5-(propyn-1-yl)-1-(β-D-arabinofuranosyl)uracil. A very short C≡C triple bond

1984 ◽  
Vol 62 (1) ◽  
pp. 147-152 ◽  
Author(s):  
Mlroslaw Cygler ◽  
Wayne F. Anderson ◽  
Jerzy Giziewicz ◽  
Morris J. Robins
Keyword(s):  
Triple Bond ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Pyrimidine Ring ◽  
Side Chain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anti Conformation ◽  
Sugar Ring ◽  
Glycosidic Torsion Angle

The crystal structure of 5-(propyn-1-yl)-1-(β-D-arabinofuranosyl)uracil, an analog of the active antiherpes nucleoside 1-(β-D-arabinofuranosyl)thymine, was determined by X-ray diffraction. The compound crystallizes in the space group P212121 with a = 4.925(1), b = 14.326(2), c = 17.454 Å. Reflections were measured on a diffractometer and the structure was solved by direct methods. Least-squares refinement converged at R = 0.032 for 1159 observed reflections. The sugar ring exhibits an 3E or a C(3′)endo conformation with a pseudorotation angle P = 28.3° and puckering amplitude τm = 31.7°. The orientation of the —CH2OH side chain is g+. The base is in an anti conformation with respect to the sugar ring, with a glycosidic torsion angle χ = 33.7°. Changes in the C(5)—C(6) and C(6)—N(1) bond lengths suggest some interaction of the propynyl group with the pyrimidine ring. The C≡C bond length of 1.121 Å is very short. Its shortening could result from intermolecular interactions with the neighboring pyrimidine ring and nearby oxygen atoms.

High-Temperature Neutron and X-ray Diffraction Study of Fast Sodium Transport in Alluaudite-type Sodium Iron Sulfate

2016 ◽  
Vol 28 (7) ◽  
pp. 2393-2399 ◽  
Author(s):  
Shin-ichi Nishimura ◽  
Yuya Suzuki ◽  
Jiechen Lu ◽  
Shuki Torii ◽  
Takashi Kamiyama ◽  
...  
Keyword(s):  
High Temperature ◽  
Diffraction Study ◽  
Sodium Transport ◽  
Iron Sulfate ◽  
X Ray Diffraction ◽  
X Ray
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