Search results for "carbon"
showing 10 items of 6057 documents
Microbial biomass carbon dynamics in a long-term tillage and crop rotation experiment under semiarid Mediterranean conditions
2015
Microbial biomass carbon (MBC) of soil is an important ecological indicator of nutrient cycling and soil fertility. In addition, it responds to the changes of soil fertility more rapidly than soil organic matter. The aim of the present work was to evaluate the effect of a long-term implementation of a conservative soil management strategy (No Tillage [NT]) compared to the inversion tillage (conventional tillage [CT]) on the soil MBC in a range of crops - continuous durum wheat (WW), wheat after fababean (FW) and faba bean after wheat (WF). MBC of NT plots was higher than CT. In addition, the content of MBC varied with sampling time during the growing season; this variation did not show a co…
Monitoring soil organic carbon variations in organic farming by proximal sensing
2014
It has been widely It has been widely recognized the crucial role of soil monitoring in assessing the effectiveness of the soil measures and agro-environment schemes passed by Regional and local administration in complying the EU’s Common Agricultural Policy to soil protection. The costs of soil monitoring however are substantial and the reliability of the results often questionable. A reason is that the monitoring activity commonly consists of a network of sampling points which are then spatialized through different inference models. This methodology does not often enable a reliable estimation at the fi eld scale, that is the scale where the measures are foreseen and fi nanced. The organic…
Synthesis of trifluoromethylated 2-benzoyl- and 3-aminoimidazoles from ring rearrangement of 1,2,4-oxadiazole derivative
2008
Fluoroalkylated 2-ylamino-imidazoles have been synthesized by reaction of 3-amino-5-phenyl-1,2,4-oxadiazole with fluorinated b-dicarbonyl compounds and subsequent base-induced BoultoneKatritzky Rearrangement (BKR) of the isolated b-enaminocarbonyl intermediate. Alternatively, one-pot reactions performed in the presence of Montmorillonite K10 favoured the condensation at the 3-amino moiety of the oxadiazole and, in some cases, allowed the direct synthesis of 2-benzoylamino-imidazoles. Hydrolysis of 2-benzoylamino-imidazoles easily yielded fluorinated 2-amino-imidazoles targets.
Double-CO32− Centered [CoII5] Wheel and Modeling of Its Magnetic Properties
2010
A high-spin Co(II) cluster with a rare pentagonal molecular structure and formula [Co(5)(CO(3))(2)(bpp)(5)]ClO(4) (1; Hbpp is 2,6-bis(phenyliminomethyl)-4-methylphenolate) has been synthesized and characterized by single-crystal X-ray diffraction. This topology arises from fusing five [Co(2)(bpp)] moieties in a cyclic manner around two CO(3)(2-) central ligands, resulting in propeller-like configuration. The irregular coordination of the carbonate ions to the metal centers results in a combination of coordination numbers (CNs) of the Co(II) ions of five and six. The bulk magnetization of this complicated magnetically exchanged system has been modeled successfully by employing a matrix diago…
Ruthenium(II) carbonyl compounds with the 4′-chloro-2,2′:6′,2′′-terpyridine ligand
2017
The RuII atoms in the crystal structures of two new potential catalyst precursors, [Ru(Tpy-Cl)(CO)2Cl][Ru(CO)3Cl3] and [Ru(Tpy-Cl)(CO)2Cl2] (Tpy-Cl = 4′-chloro 2,2′:6′,2′′-terpyridine-κ3 N), exhibit distorted octahedral coordination spheres.
Crystal structure of tricarbonyl(N-diphenylphosphanyl-N,N′-diisopropyl-P-phenylphosphonous diamide-κ2 P,P′)cobalt(I) tetracarbonylcobaltate(−…
2014
The title compound {Co(CO)3[Ph2PN(i-Pr)P(Ph)N(H)i-Pr]}[Co(CO)4] is an ionic species consisting of a Co(CO)3[Ph2PN(i-Pr)P(Ph)N(H)i-Pr] cation and a [Co(CO)4] anion.
A Simple Complex on the Verge of Breakdown: Isolation of the Elusive Cyanoformate Ion
2014
Cyanide Hitches a Ride Cyanide is a by-product of the biosynthesis of ethylene in plants and it has been somewhat puzzling how the ion is safely removed before it can shut down enzymatic pathways by coordination to catalytic iron centers. A proposed mechanism has implicated the cyanoformate ion—essentially, a weak adduct of cyanide and carbon dioxide—as the initial product, although its lifetime was uncertain. Murphy et al. (p. 75 ; see the Perspective by Alabugin and Mohamed ) crystallized this previously elusive adduct and found that its solution-phase stability varies inversely with the dielectric properties of the medium. The results bolster a picture in which the adduct shuttles the cy…
The head-to-head photodimer of indeno-indene.
2020
Irradiation of 1-(1-benzocyclobutenylidene)benzocyclobutene gives indenoindene and its head-to-head photodimer nonacyclo[9.7.7.72,10.01,11.02,10.03,8.012,17.019,24.026,31]dotriaconta-3,5,7,12,14,16,19,21,23,26,28,30-dodecaene, C32H24. The molecule is built from four essentially planar indane units attached to an elongated cyclobutane ring. In the crystal, C—H...π interactions connect molecules into layers parallel to the bc plane.
{Bis[2-(diisopropylphosphanyl)ethyl]amine}carbonyl(tetrahydroborato)cobalt(I)
2018
In the structure of title borohydride pincer complex, [Co(BH4)(C16H37NP2)(CO)], the cobalt(I) metal exhibits a distorted square-pyramidal coordination geometry with the basal positions occupied by the P and N atoms of the tridentate ligand and by the C atom of the carbon monoxide ligand. In the crystal, molecules interact only by van der Waals forces.
Crystal structure of thecisandtranspolymorphs of bis[μ-2-(1,3-benzothiazol-2-yl)phenolato]-κ3N,O:O;κ3O:N,O-bis[fac-tricarbonylrhenium(I)]
2017
The title dinuclear complex, [Re2(C13H8NOS)2(CO)6], crystallizes in two polymorphs where the 2-(1,3-benzothiazol-2-yl)phenolate ligands and two carbonyl groups aretrans- (I) orcis-arranged (II) with respect to the [Re2O2(CO)4] core. PolymorphsIandIIexhibit a crystallographically imposed centre of symmetry and a twofold rotation axis, respectively. The structures may be described as being formed by two octahedrally distorted metal-coordinating units fused through μ-oxido bridges, leading to edge-sharing dimers. The crystal packing is governed by C—H...O hydrogen-bonding interactions, forming chains parallel to thecaxis inIand a three-dimensional network inII.