FeCsub.5Hsub.5Nsub.2N(CN)sub.2sub.2 (1) was synthesized from a reaction of stoichiometric amounts of NaN(CN)sub.2 and FeClsub.2·4Hsub.2O in a methanol/pyridine solution. Single-crystal and powder ...diffraction show that 1 crystallizes in the monoclinic space group I2/m (no. 12), different from MnCsub.5Hsub.5Nsub.2N(CN)sub.2sub.2 (P2sub.1/c, no. 14) due to tilted pyridine rings, with a = 7.453(7) Å, b = 13.167(13) Å, c = 8.522(6) Å, β = 114.98(6)° and Z = 2. ATR-IR, AAS, and CHN measurements confirm the presence of dicyanamide and pyridine. Thermogravimetric analysis shows that π-stacking interactions of the pyridine rings play an important role in structural stabilization. Based on DFT-optimized structures, a chemical bonding analysis was performed using a local-orbital framework by projection from a plane-wave basis. The resulting bond orders and atomic charges are in good agreement with the expectations based on the structure analysis. SQUID magnetic susceptibility measurements show a high-spin state Fesup.II compound with predominantly antiferromagnetic exchange interactions at lower temperatures.
Calcium catches dinitrogen Funk, Michael
Science (American Association for the Advancement of Science),
03/2021, Letnik:
371, Številka:
6534
Journal Article
This book focuses on the fundamental and applied research of the non-destructive estimation and diagnosis of crop leaf and plant nitrogen status and in-season nitrogen management strategies based on ...leaf sensors, proximal canopy sensors, unmanned aerial vehicle remote sensing, manned aerial remote sensing and satellite remote sensing technologies. Statistical and machine learning methods are used to predict plant-nitrogen-related parameters with sensor data or sensor data together with soil, landscape, weather and/or management information. Different sensing technologies or different modelling approaches are compared and evaluated. Strategies are developed to use crop sensing data for in-season nitrogen recommendations to improve nitrogen use efficiency and protect the environment.
Solving energy and environmental problems through solar‐driven photocatalysis is an attractive and challenging topic. Hence, various types of photocatalysts have been developed successively to ...address the demands of photocatalysis. Graphene‐based materials have elicited considerable attention since the discovery of graphene. As a derivative of graphene, nitrogen‐doped graphene (NG) particularly stands out. Nitrogen atoms can break the undifferentiated structure of graphene and open the bandgap while endowing graphene with an uneven electron density distribution. Therefore, NG retains nearly all the advantages of original graphene and is equipped with several novel properties, ensuring infinite possibilities for NG‐based photocatalysis. This review introduces the atomic and band structures of NG, summarizes in situ and ex situ synthesis methods, highlights the mechanism and advantages of NG in photocatalysis, and outlines its applications in different photocatalysis directions (primarily hydrogen production, CO2 reduction, pollutant degradation, and as photoactive ingredient). Lastly, the central challenges and possible improvements of NG‐based photocatalysis in the future are presented. This study is expected to learn from the past and achieve progress toward the future for NG‐based photocatalysis.
Nitrogen‐doped graphene plays a significant role in photocatalysis. Rational design, preparation, and understanding the mechanism of N‐doped graphene‐based photocatalysts provides a new opportunity to further enhance the photocatalytic performance. The research progress, atomic and band structures, photocatalytic mechanism, synthesis strategy, unique advantages, and wide application of N‐doped graphene in photocatalysis are highlighted.
Too much of a good thing Sutton, Mark A; Oenema, Oene; Erisman, Jan Willem ...
Nature (London),
04/2011, Letnik:
472, Številka:
7342
Journal Article
Recenzirano
Odprti dostop
All biological systems need reactive nitrogen, but historically it has been in short supply. ... the end of the nineteenth century, the main agricultural source was fixation of N2 by symbiotic ...bacteria in legumes planted for that purpose, combined with careful recycling of the limited amount of nitrogen in manure.
Poor growth is often observed in artificial young forests due to insufficient inorganic nitrogen in karst soils. However, little is known about the assimilatory demand of the whole plant for nitrate ...and the partitioning of nitrate assimilation in roots and leaves in woody plants grown in karst habitats. In this study, Broussonetia papyrifera (L.) Vent (B. papyrifera) seedlings were grown under nearly hydroponic conditions. The isotope mass balance approach was employed to quantify the δsup.15N values of the N assimilates in plant organs and in whole plants for B. papyrifera seedlings grown at different nitrate concentrations. The δsup.15N values of the N assimilates in the whole B. papyrifera seedlings showed a rising trend with increasing nitrate concentration. Increasing the supply of nitrate decreased the leaf-root difference in the δsup.15N values of the N assimilates for B. papyrifera seedlings. Quantifying the δsup.15N values of N assimilates in the whole B. papyrifera seedlings grown under different nitrate concentrations contributes to estimating the assimilatory demand of the B. papyrifera seedlings for nitrate. The leaf-root difference in the δsup.15N values of the N assimilates can be used to estimate the partitioning of nitrate assimilation in the roots and leaves.
The paper presents the results of studies of argon-nitrogen plasma of a non-self-sustained low-pressure glow discharge with a hollow cathode by optical emission spectrometry. The plasma was generated ...in a mixture of Ar-N.sub.2 gases with an argon percentage from 0 to 100% at a total pressure of 1 Pa. The discharge current and voltage were maintained constant and amounted to 18 A and 165 V, respectively. A significant increase in the amount of Ar.sup.+ (up to 30%) at a nitrogen content of 10-25% was shown, which is associated with a shift in the reaction of charge exchange of nitrogen with argon towards the generation of argon ions. It was found that at a low partial pressure of nitrogen (approximately equal to 10%), a sharp increase in the content of atomic nitrogen is observed which is probably due to the dissociation of nitrogen molecules upon collisions with an excited argon atom. Keywords: low-pressure glow discharge, hollow cathode, plasma diagnostics, optical emission spectrometry, nitrogen dissociation, atomic nitrogen, argon plasma.
Human mobilization and use of reactive nitrogen (Nr) has been one of the major aspects of global change over the past century. Nowhere has that change been more dramatic than in China, where annual ...net Nr creation increased from 9.2 to 56 Tg from 1910 to 2010. Since 1956, anthropogenic Nr creation exceeded natural Nr creation, contributing over 80% of total Nr until 2010. There is great interest and uncertainty in the fate and effects of this Nr in China. Here, a comprehensive inventory of Nr in China shows that Nr (including recycled Nr) has continuously and increasingly accumulated on land (from 17 to 45 Tg), accompanied by increasing transfers to the atmosphere (before deposition; from 7.6 to 20 Tg), inland waters (from 2.7 to 9.6 Tg), and coastal waters (from 4.5 to 7.7 Tg) over the past 30 y. If current trends continue, Nr creation from human activities will increase to 63 Tg by 2050, raising concerns about deleterious environmental consequences for land, air, and water at regional and global scales. Tremendous amounts of Nr have accumulated in plants, soils, and waters in China over the past 30 y, but the retention capacity of the terrestrial landscape seems to be declining. There is a possibility that the negative environmental effects of excessive Nr may accelerate in coming decades, increasing the urgency to alter the trajectory of increasing Nr imbalance. Here, a conceptual framework of the relationships between human drivers and Nr cycling in China is oriented and well-targeted to Chinese abatement strategies for Nr environmental impact.
A new Co(II) perchlorate complex of the bis-morpholino/benzoimidazole-s-triazine ligand, 4,4′-(6-(1H-benzodimidazol-1-yl)-1,3,5-triazine-2,4-diyl)dimorpholine (BMBIT), was synthesized and ...characterized. The structure of the new Co(II) complex was approved to be Co(BMBIT)sub.2(Hsub.2O)sub.4(ClOsub.4)sub.2*Hsub.2O using single-crystal X-ray diffraction. The Co(II) complex was found crystallized in the monoclinic crystal system and P21/c space group. The unit cell parameters are a = 22.21971(11) Å, b = 8.86743(4) Å, c = 24.38673(12) Å and β = 113.4401(6)°. This heteroleptic complex has distorted octahedral coordination geometry with two monodenatate BMBIT ligand units via the benzoimidazole N-atom and four water molecules as monodentate ligands. The hydration water and perchlorate ions participated significantly in the supramolecular structure of the Co(BMBIT)sub.2(Hsub.2O)sub.4(ClOsub.4)sub.2*Hsub.2O complex. Analysis of dsub.norm map and a fingerprint plot indicated the importance of O···H, N···H, C···H, C···O, C···N and H···H contacts. Their percentages are 27.5, 7.9, 14.0, 0.9, 2.8 and 43.5%, respectively. The sensitivity of some harmful microbes towards the studied compounds was investigated. The Co(II) complex has good antifungal activity compared to the free BMBIT which has no antifungal activity. The Co(II) complex has good activity against B. subtilis, S. aureus, P. vulgaris and E. coli while the free BMBIT ligand has limited activity only towards B. subtilis and P. vulgaris. Hence, the Co(BMBIT)sub.2(Hsub.2O)sub.4(ClOsub.4)sub.2*Hsub.2O complex has broad spectrum antimicrobial action compared to the free BMBIT ligand.
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